Non-contact electrical parameter measurement systems

Abstract

To provide measurement of AC electrical parameters in an insulated wire without requiring a galvanic connection between the insulated wire and a test probe.SOLUTION: A measurement system may include a housing that includes both a non-contact voltage sensor and a non-contact current sensor. The measurement system obtains measurements from the voltage sensor and the current sensor during a measurement time interval, and processes the measurements to determine AC electrical parameters of the insulated wire. The AC electrical parameters may be presented to an operator via a visual indicator device (e.g., display, lights). The AC electrical parameters may additionally or alternatively be communicated to an external device via a wired and / or wireless communications interface. The measurement system may include an alignment feedback sensor that provides a user with feedback regarding the mechanical alignment of the insulated wire relative to the voltage sensor and the current sensor.SELECTED DRAWING: Figure 28

Description

[Technical field]

[0001] The present disclosure relates generally to measuring electrical properties, and more particularly, to non-contact measurement of electrical parameters in an electrical circuit. [Background technology]

[0002] A voltmeter is an instrument used to measure voltage in an electrical circuit. Instruments that measure more than one electrical property are called multimeters or digital multimeters (DMMs) and are operative to measure several parameters commonly required for service, troubleshooting, and maintenance applications. Such parameters typically include alternating current (AC) voltage and current, direct current (DC) voltage, and current. (direct current, DC) voltage and current, as well as resistance or continuity. Other parameters such as power quality, frequency, capacity and temperature can also be measured to meet the requirements of a particular application.

[0003] For a conventional voltmeter or multimeter to measure AC voltage and / or current, it is necessary to place at least one measurement electrode or probe in galvanic contact with a conductor, which often requires prior cutting a portion of the insulation of an insulated wire, breaking a circuit, and / or providing a terminal for the measurement. The step of contacting a probe with an exposed wire or terminal not only requires exposed wire or terminal for galvanic contact, but can be relatively dangerous due to the risk of shock or electrocution. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication 2014-106220 Summary of the Invention [Means for solving the problem]

[0005] The non-contact measurement system can be summarized as comprising: a housing having a front end; a voltage sensor positioned proximate the front end of the housing that, during operation, senses a voltage in the insulated wire without galvanic contact with the insulated wire; a current sensor positioned proximate the front end of the housing that, during operation, senses a voltage in the insulated wire without galvanic contact with the insulated wire; and at least one processor positioned within the housing, the at least one processor operably coupled to the voltage sensor and the current sensor; and, during operation, the at least one processor receives from the voltage sensor during a measurement time interval a voltage sensor signal obtained by the voltage sensor indicative of a voltage in the insulated wire and receives from the current sensor during the measurement time interval a current sensor signal obtained by the current sensor indicative of a current in the insulated wire and determines at least one alternating current (AC) electrical parameter based at least in part on the received voltage sensor signal and current sensor signal.

[0006] The current sensor may include a magnetic field sensor. The voltage sensor may include one of a capacitive divider voltage sensor, a reference signal voltage sensor, or a multi-capacitor voltage sensor. The voltage sensor may include a reference signal voltage sensor that, in operation, senses a reference signal in the insulated wire without galvanic contact with the insulated wire, and the at least one processor receives the reference signal and determines at least one characteristic of the current flowing through the insulated wire based at least in part on the received reference signal. The at least one AC electrical parameter may be at least one of power, phase, frequency, harmonics, or energy. During operation, the at least one processor can determine a plurality of AC electrical parameters based at least in part on the received voltage sensor signal and current sensor signal.

[0007] The non-contact measurement system may further include a display operably coupled to the at least one processor, wherein during operation, the at least one processor may cause the display to indicate at least one of the AC electrical parameters.

[0008] During operation, the at least one processor can cause the display to show at least one of a waveform or a graph associated with the at least one AC electrical parameter.

[0009] The non-contact measurement system may further include a communication interface operably coupled to the at least one processor, and during operation, the at least one processor may send data to the at least one external device via the communication interface, the data relating to at least one of the voltage sensor signal, the current sensor signal, or the determined at least one AC electrical parameter.

[0010] The communication interface may include a wireless communication interface operable to wirelessly transmit data to at least one external device.

[0011] The non-contact measurement system may further include at least one external device including a display, a communications interface that, in operation, receives data sent by the communications interface of the non-contact measurement system, and at least one processor operably coupled to the display and the communications interface, and, in operation, the at least one processor receives data from the non-contact measurement system via the communications interface and causes the display to indicate at least one AC electrical parameter.

[0012] The non-contact measurement system may further include an alignment feedback sensor operably coupled to the at least one processor and positioned proximate a front end of the housing of the non-contact measurement system, where in operation the alignment feedback sensor generates an alignment feedback sensor signal indicative of a current alignment of the insulated wire relative to the voltage sensor and the current sensor, and an indicator device operably coupled to the at least one processor, where in operation the at least one processor receives the alignment feedback sensor signal from the alignment feedback sensor and causes the indicator device to provide an alignment indication to a user of the non-contact measurement system based at least in part on the received alignment feedback sensor signal.

[0013] The indicator device can include at least one of a visual indicator device or an audible indicator device. The indicator device can include at least one of a display or a plurality of lights, and in operation, the at least one processor can cause the indicator device to provide an alignment indication to a user including a plurality of colors, each of the plurality of colors corresponding to a different level of alignment of the insulated wire relative to the voltage sensor and the current sensor. In operation, the at least one processor can cause the indicator device to provide an indication of measurement accuracy based at least in part on the received alignment feedback sensor signal. In operation, the at least one processor can cause the indicator device to provide an indication of an energized circuit proximate to the insulated wire under test based at least in part on the received alignment feedback sensor signal. can be done.

[0014] A method of operating a non-contact measurement system to determine at least one alternating current (AC) electrical parameter in an insulated wire may be summarized as including: sensing a voltage in the insulated wire during a measurement time interval without galvanically contacting the insulated wire via a voltage sensor positioned within a housing of the non-contact measurement system; sensing a current in the insulated wire during a measurement time interval without galvanically contacting the insulated wire via a current sensor positioned within the housing of the non-contact measurement system; and determining, via at least one processor positioned within the housing of the non-contact measurement system, the at least one alternating current (AC) electrical parameter based at least in part on the sensed voltage and the sensed current.

[0015] Sensing the voltage can include sensing the voltage using one of a capacitive divider voltage sensor, a reference signal voltage sensor, or a multi-capacitor voltage sensor, and sensing the current can include sensing the current using a magnetic field sensor. Determining the at least one AC electrical parameter can include determining at least one of power, phase, frequency, harmonics, or energy based at least in part on the sensed voltage and the sensed current.

[0016] The method of operating a non-contact measurement system to determine at least one alternating current (AC) electrical parameter within an insulated electrical wire may further include presenting an indication of the at least one AC electrical parameter to a user of the non-contact measurement system.

[0017] The non-contact measurement system includes a housing having a front end, a voltage sensor positioned proximate the front end that, during operation, senses a voltage in the insulated wire during a measurement time interval without galvanically contacting the insulated wire, a current sensor positioned proximate the front end that, during operation, senses a current in the insulated wire during a measurement time interval without galvanically contacting the insulated wire, a feedback sensor positioned proximate the front end, a voltage sensor positioned proximate the front end that, during operation, senses a voltage in the insulated wire during a measurement time interval without galvanically contacting the insulated wire, a current sensor positioned proximate the front end that, during operation, senses a current in the insulated wire during a measurement time interval without galvanically contacting the insulated wire, a feedback sensor positioned proximate the front end, and an inductor positioned on a surface of the housing. The non-contact measurement system may be summarized as including an indicator device and at least one processor positioned within the housing, the at least one processor communicatively coupled to the voltage sensor, the current sensor, the alignment feedback sensor, and the indicator device, wherein, during operation, the at least one processor determines at least one alternating current (AC) electrical parameter based at least in part on the sensed voltage and the sensed current, receives alignment feedback sensor signals from the alignment feedback sensor, the alignment feedback sensor, and the current sensor indicative of a current alignment of the insulated electrical wire relative to the voltage sensor, and causes the indicator device to provide an alignment indication to a user of the non-contact measurement system based at least in part on the received alignment feedback sensor signals. [Brief description of the drawings]

[0018] In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of components in the drawings are not necessarily drawn to scale. For example, the shapes of the various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to facilitate legibility of the drawings. Additionally, the particular shapes of the elements as depicted are not necessarily intended to be construed in any way as relating to the actual shape of the particular elements. They are not intended to convey information, but may simply be selected for ease of recognition in the drawings. [Figure 1A] FIG. 1A is a pictorial diagram of an environment in which an operator can use a non-contact voltage measurement system including a reference signal type voltage sensor to measure AC voltages present in an insulated electrical wire without requiring galvanic contact with the wire, according to one illustrated implementation. [Figure 1B] FIG. 1B is a top view of the non-contact voltage measurement system of FIG. 1A showing the coupling capacitance formed between the insulated wire and a conductive sensor of the non-contact voltage measurement system, the insulated conductor current components, and the human body capacitance between the non-contact voltage measurement system and an operator, according to one illustrated implementation. [Diagram 2] FIG. 2 is a schematic diagram of various internal components of a non-contact voltage measurement system, according to one illustrated implementation. [Diagram 3] FIG. 3 is a block diagram illustrating various signal processing components of a non-contact voltage measurement system according to one illustrated implementation. [Figure 4] FIG. 4 is a schematic diagram of a non-contact voltage measurement system that performs a fast Fourier transform (FFT), according to one illustrated implementation. [Diagram 5] FIG. 5 is a block diagram of a non-contact voltage measurement system implementing an analog electronic filter according to another embodiment of signal and reference signal separation. [Figure 6] FIG. 6 is a schematic circuit diagram of a non-contact voltage measurement system according to one illustrative implementation. [Figure 7A]FIG. 7A is a schematic diagram of a non-contact voltage measurement system showing various leakage and stray capacitances according to one illustrated implementation. [Figure 7B] FIG. 7B is a schematic diagram of a non-contact voltage measurement system showing various leakage and stray capacitances and including compensation of the reference voltage signal according to one illustrative implementation. [Figure 7C] FIG. 7C shows an example sensor arrangement for the system of FIG. 7B according to one illustrative implementation. [Figure 8] FIG. 8 is a schematic circuit diagram of a non-contact voltage measurement system showing the capacitance between a sensor of the non-contact voltage measurement system and external ground according to one illustrated implementation. [Figure 9A] FIG. 9A is a schematic circuit diagram of a non-contact voltage measurement system showing the capacitance between the internal ground guard and the external ground of the non-contact voltage measurement system according to one illustrated implementation. [Figure 9B] FIG. 9B is a schematic circuit diagram of a non-contact voltage measurement system showing the capacitance between the internal ground guard and the external ground of the non-contact voltage measurement system according to one illustrated implementation. [Figure 10] FIG. 10 is a perspective view of a sensor and internal ground guard assembly of a non-contact voltage measurement system according to one illustrated implementation. [Figure 11] FIG. 11 is a cross-sectional view of a "U" or "V" shaped sensor front end of a non-contact voltage measurement system according to one illustrated implementation. [Figure 12] FIG. 12 is an elevational view of the front end of an arcuate shaped sensor of a non-contact voltage measurement system according to one illustrated implementation. [Figure 13] FIG. 13 is a perspective view of a cylindrical sensor front end of a non-contact voltage measurement system according to one illustrated implementation. [Figure 14A] FIG. 14A is a top view of the sensor front end of a non-contact voltage measurement system with the guard ring clamp of the internal ground guard in a closed position according to one illustrated implementation. [Figure 14B]FIG. 14B is a top view of the front end of the non-contact voltage measurement system shown in FIG. 14A with the guard ring clamp of the internal ground guard in an open position according to one illustrated implementation. [Figure 15] FIG. 15 is a perspective view of a portion of the front end of the sensor of FIG. 14A with the guard ring clamp of the internal ground guard removed according to one illustrated implementation. [Figure 16] FIG. 16 is a pictorial diagram of an environment in which an operator can use a non-contact voltage measurement system including a capacitive divider-type voltage sensor to measure AC voltage present in an insulated electrical wire without requiring galvanic contact with the wire, according to one illustrated implementation. [Figure 17] FIG. 17 is a top view of the non-contact voltage measurement system of FIG. 16 according to one illustrated implementation. [Figure 18] FIG. 18 is a high-level block diagram of a non-contact voltage measurement system according to one illustrated implementation. [Figure 19] FIG. 19 is a schematic diagram of a non-contact voltage measurement system including a variable illustrated capacitance subsystem utilizing two capacitors according to one implementation. [Figure 20] FIG. 20 is a schematic circuit diagram of the non-contact voltage measurement system of FIG. 19 according to one illustrated implementation. [Figure 21] FIG. 21 is a schematic diagram of a non-contact voltage measurement system including a variable illustrated capacitance subsystem utilizing three capacitors, according to one implementation. [Figure 22] FIG. 22 is a flow diagram of a method of operating a non-contact voltage measurement system to measure AC voltage in an insulated wire without galvanic contact with the wire, according to one illustrated implementation. [Figure 23A] FIG. 23A is a pictorial diagram of an environment in which an operator can use a non-contact voltage measurement system including a multi-capacitor voltage sensor according to one illustrated implementation to measure AC voltages present in an insulated electrical wire without requiring galvanic contact with the wire. [Figure 23B]FIG. 23B is a top view of the non-contact voltage measurement system of FIG. 23A showing a coupling capacitance formed between an insulated wire and a conductive sensor of the non-contact voltage measurement system according to one illustrated implementation. [Figure 24] FIG. 24 is a schematic diagram of various internal components of a non-contact voltage measurement system according to one illustrated implementation. [Diagram 25] FIG. 25 is a schematic diagram showing a conductive sensor of a non-contact voltage measurement system positioned in proximity to an insulated wire under test, according to one illustrated implementation. [Figure 26A] FIG. 26A is a top view of first and second conductive sensors and an internal ground guard of a non-contact voltage measurement system showing example configurations of the first and second conductive sensors according to one illustrated implementation. [Figure 26B] FIG. 26B is a top view of a third conductive sensor and an internal ground guard of a non-contact voltage measurement system showing an exemplary shape of the third conductive sensor according to one illustrated implementation. [Figure 27] FIG. 27 is a cross-sectional view of the front or probe end of a non-contact voltage measurement system according to one illustrated implementation. [Figure 28] FIG. 28 is a schematic block diagram of a measurement system, according to one illustrative implementation. [Figure 29] FIG. 29 is a schematic block diagram of a measurement system operating as a remote sensor according to one illustrative implementation. [Diagram 30] FIG. 30 is a front end view of a measurement system that provides alignment feedback. [Diagram 31] FIG. 31 is a front elevation view of an exemplary measurement system that can incorporate at least a portion of the functionality of the present disclosure. [Diagram 32] FIG. 32 is a front elevation view of an exemplary measurement system that can incorporate at least a portion of the functionality of the present disclosure. [Diagram 33] FIG. 33 is a front elevation view of an exemplary measurement system that can incorporate at least a portion of the functionality of the present disclosure. [Diagram 34]FIG. 34 is a front elevation view of an exemplary measurement system that can incorporate at least a portion of the functionality of the present disclosure. [Diagram 35] FIG. 35 is a front elevation view of an exemplary measurement system that can incorporate at least a portion of the functionality of the present disclosure. [Diagram 36] FIG. 36 is a front elevation view of an exemplary measurement system that can incorporate at least a portion of the functionality of the present disclosure. [Figure 37] FIG. 37 is a front elevation view of an exemplary measurement system that can incorporate at least a portion of the functionality of the present disclosure. [Figure 38] FIG. 38 is a front elevation view of an exemplary measurement system that can incorporate at least a portion of the functionality of the present disclosure. [Figure 39] FIG. 39 is a front elevation view of an exemplary measurement system that can incorporate at least a portion of the functionality of the present disclosure. [Diagram 40] FIG. 40 is a front elevation view of an exemplary measurement system that can incorporate at least a portion of the functionality of the present disclosure. [Diagram 41] FIG. 41 is a front elevation view of an exemplary measurement system that can incorporate at least a portion of the functionality of the present disclosure. [Figure 42A] FIG. 42A is a front elevation view of an exemplary measurement system that can incorporate at least a portion of the functionality of the present disclosure. [Figure 42B] FIG. 42B is a left side view of the measurement system of FIG. 42A. [Diagram 43] FIG. 43 is a pictorial diagram of an environment in which an operator can use a non-contact current measurement system, according to one illustrated implementation, to measure AC current present in an insulated wire without requiring galvanic contact with the insulated wire. [Figure 44A] FIG. 44A is a front elevational view of a non-contact current measurement system including an adjustable clamp assembly shown with a clamp member of the adjustable clamp assembly spaced apart from an insulated wire. [Figure 44B]FIG. 44B is a front elevational view of the non-contact current measurement system of FIG. 44A shown with an insulated wire clamped by the adjustable clamp assembly. [Diagram 45] FIG. 45 is a front elevation view of another implementation of a non-contact current measurement system according to one illustrated implementation. [Figure 46] FIG. 46 is a front elevation view of another implementation of a non-contact current measurement system according to one illustrated implementation. [Figure 47] FIG. 47 is a front elevation view of another implementation of a non-contact current measurement system in accordance with one illustrated implementation. [Figure 48] FIG. 48 is a schematic block diagram of a non-contact current measurement system according to one illustrated implementation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The disclosed systems and methods advantageously provide for the measurement of one or more alternating current (AC) electrical parameters in an insulated wire without requiring a galvanic connection between the insulated wire and a test electrode or probe. Generally, a "non-contact measurement system" is disclosed herein that includes both a non-contact current sensor and a housing that includes a non-contact voltage sensor. Non-limiting examples of types of non-contact current sensors include magnetic field sensors, such as anisotropic magnetoresistive (AMR) sensors, giant magnetoresistive (GMR) sensors, fluxgate sensors, SQUID sensors, optical fiber sensors, optically excited sensors, nuclear procession sensors, search coil sensors, magnetotransistor sensors, magnetodiode sensors, optical magneto sensors, Hall effect sensors, Rogowski coils, current transformers, or other types of magnetic field sensors. Non-limiting examples of types of non-contact voltage sensors include capacitive divider voltage sensors, reference signal voltage sensors, multi-capacitor voltage sensors, and the like. Exemplary implementations of the voltage and current sensors are discussed in further detail below.

[0020] The non-contact measurement systems discussed herein may include at least one processor that receives a voltage sensor signal and a current sensor signal from a voltage sensor and a current sensor, respectively. The voltage sensor signal is indicative of the voltage in the insulated wire, and the current sensor signal is indicative of the current in the insulated wire. The voltage sensor signal and the current sensor signal may be common or overlapping. The measurements may be taken by the respective voltage and current sensors during a common measurement time interval, which may be relatively short in duration (e.g., 10 milliseconds (ms), 100 ms, 1 second, 10 seconds). For example, the voltage and current sensors may take measurements at least partially in parallel with one another. As another example, one of the voltage and current sensors may take a measurement substantially immediately after the other of the voltage and current sensors takes a measurement, such that the measurements are taken approximately simultaneously and within a common measurement time interval. In some implementations, the voltage and current sensors may be operable to repeatedly take measurements at specified intervals (e.g., every 10 ms, every 100 ms, every second, every 10 seconds). Typically, both the voltage and current sensors take their respective measurements within a measurement time interval, which is short enough such that pairs of voltage and current measurements correspond to one another, allowing one or more AC electrical parameters (e.g., power, stage) to be derived or determined using the taken current and voltage measurements.

[0021] In at least some implementations, the determined AC electrical parameters can be indicated to an operator via a visual indicator device (e.g., display, lighting). The determined one or more AC electrical parameters can additionally or alternatively be communicated to an external device via a wired and / or wireless communication interface. The AC electrical parameters can include power, phase, frequency, harmonics, energy, and the like. Additionally, as discussed below with reference to FIG. 30, the non-contact measurement system of the present disclosure can include an alignment feedback sensor that provides feedback regarding the mechanical alignment of the insulated wire relative to the voltage sensor and the current sensor. The alignment feedback can be provided to a user of the non-contact measurement system via an indicator device (e.g., display, lighting, speaker, buzzer). In at least some implementations, the alignment feedback sensor can also provide feedback related to the presence of nearby energized circuits that the user may want to avoid.

[0022] First, an example of a reference signal type non-contact voltage sensor or system is discussed with reference to Figures 1-15. Then, an example of a capacitive divider type voltage sensor or system is discussed with reference to Figures 16-22. Then, an example of a multi-capacitor type voltage sensor or system is discussed with reference to Figures 23A-27. Then, various examples of non-contact measurement systems that can include at least a portion of the functionality disclosed herein are discussed with reference to Figures 28-42B. Finally, an example of a non-contact current measurement system is discussed with reference to Figures 43-48. It will be appreciated that the various features of the implementations discussed herein can be rearranged and / or combined in numerous ways to provide the desired functionality.

[0023] In the following detailed description, certain specific details are set forth to provide a thorough understanding of various embodiments of the present invention. However, those skilled in the relevant art will recognize that the implementations may be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures related to computer systems, server computers, and / or communication networks have not been shown and / or described in detail so as not to unnecessarily obscure the description of the implementations.

[0024] Throughout the following specification and claims, unless the context requires otherwise, the word "comprising" is synonymous with the word "including." The terms used herein are inclusive, that is, open-ended (i.e., do not exclude additional, unrecited elements or method acts).

[0025] References throughout this specification to "one implementation" or "an implementation" are intended to mean that the implementation is described in terms of the implementation. It means that a particular feature, structure or characteristic described is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

[0026] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. It should also be noted that the term "or" is generally employed to include "and / or" in its meaning unless the context clearly dictates otherwise. Moreover, the headings and abstracts provided herein are for convenience only and do not interpret the scope or meaning of the examples.

[0027] Reference signal type non-contact voltage measurement system In the following discussion, systems and methods are presented for measuring alternating current (AC) voltages of insulated or blank non-insulated conductors (e.g., insulated wires) without requiring a galvanic connection between the conductor and a test electrode or probe. Implementations disclosed in this section may be referred to herein as "reference signal type voltage sensors" or systems. Generally, non-galvanic contact (or "non-contact") voltage measurement systems are presented, which use capacitive sensors to measure AC voltage signals in an insulated conductor relative to ground. Such systems that do not require a galvanic connection are referred to herein as "non-contact." As used herein, "electrically coupled" includes both direct and indirect electrical coupling, unless otherwise specified.

[0028] As discussed further below, the "reference signal" systems and methods discussed below can also be used to measure at least one physical dimension of the insulated wire (e.g., insulation thickness) without requiring a galvanic connection between the conductor of the insulated wire and a sensor or electrode (the "reference signal sensor"). In at least some implementations, a non-contact current measurement system can utilize a reference signal method, with or without mechanical position feedback, to determine or estimate one or more physical dimensions of the insulated wire (e.g., conductor diameter). Such a capability can be advantageous for several reasons, including enabling a determination of the current flowing through the insulated wire with greater accuracy than can be achieved without the physical dimensional information.

[0029] FIG. 1A is a pictorial diagram of an environment 100 in which a non-contact voltage measurement system 102, including a reference signal type voltage sensor, can be used by an operator 104 to measure an AC voltage present in an insulated conductor 106 without requiring galvanic contact between the non-contact voltage measurement system and the electrical wire 106. FIG. 1B is a top view of the non-contact voltage measurement system 102 of FIG. 1A illustrating various electrical characteristics of the non-contact voltage measurement system during operation. The non-contact voltage measurement system 102 includes a housing or body 108 that includes a gripping portion or end 110 and a probe portion or end 112, also referred to herein as a front end, opposite the gripping portion. The housing 108 can also include a user interface 114 that facilitates user interaction with the non-contact voltage measurement system 102. The user interface 114 can include any number of inputs (e.g., buttons, dials, switches, touch sensors) and any number of outputs (e.g., displays, LEDs, speakers, buzzers). The non-contact voltage measurement system 102 may also include one or more wired and / or wireless communication interfaces (eg, USB, Wi-Fi®, Bluetooth®).

[0030] 1B, the probe portion 112 can include a recessed portion 116 defined by first and second extension portions 118 and 120. The recessed portion 116 receives the insulated conductor 106 (see FIG. 1A). The insulated conductor 106 includes a conductor 122 and an insulator 124 that surrounds the conductor 122. The recessed portion 116 can include a recessed portion 116 that is recessed into the first and second extension portions 118 and 120. , a sensor or electrode 126 that is disposed adjacent to the insulator 124 of the insulated wire 106 when the insulated wire is positioned within the recessed portion 116 of the non-contact voltage measurement system 102. Although not shown for clarity, the sensor 126 may be disposed inside the housing 108 to prevent physical and electrical contact between the sensor and other objects.

[0031] As shown in FIG. 1A, in use, an operator 104 can grasp the gripping portion 110 of the housing 108 and place the probe portion 112 in proximity to the insulated conductor 106 such that the non-contact voltage measurement system 102 can accurately measure the AC voltage present in the wire relative to ground (or another reference node). Although the probe end 112 is shown having a recessed portion 116, in other implementations the probe portion 112 can be configured differently. For example, in at least some implementations the probe portion 112 can include selectively flat or arcuate surfaces including movable clamps, hooks, sensors, or other types of interfaces that allow the sensor of the non-contact voltage measurement system 102 to be positioned in proximity to the insulated conductor 106. Various probe portion and sensor embodiments are discussed below with reference to FIGS. 10-15.

[0032] The operator's body serving as an earth / ground reference is only in some implementations. The functionality of the non-contact measurements discussed herein is not limited to applications measuring only against ground. The external reference can be capacitively coupled to any other potential. For example, if the external reference is capacitively coupled to another phase of a three-phase system, the phase-to-phase voltage is measured. In general, the concepts discussed herein are not limited to only references to earth using a human body capacitively connected to a reference voltage and any other reference potential.

[0033] As discussed further below, in at least some implementations, the non-contact voltage measurement system 102 measures the human body capacitance (C B ) during AC voltage measurement Although the term ground is used for node 128, the node is not necessarily earth / ground but may be connected in a galvanically isolated manner to any other reference potential by capacitive coupling.

[0034] The particular systems and methods used by the non-contact voltage measurement system 102 to measure AC voltages are discussed below with reference to FIGS.

[0035] 2 shows a schematic diagram of various internal components of the non-contact voltage measurement system 102 also shown in FIGS. 1A and 1B. In this embodiment, the conductive sensor 126 of the non-contact voltage measurement system 102 is substantially "V-shaped" and is positioned proximate to the insulated conductor 106 under test and capacitively couples with the conductor 122 of the insulated conductor 106, forming a sensor coupling capacitor (C O ) is formed The operator 104 who operates the non-contact voltage measurement system 102 measures the human body capacitance (C B ) 1B and 2, the AC voltage signal (V O ) is the insulated conductor current component or "signal current" (I O ) in series with a coupling capacitor (C O ) and human body capacity (C B ) over the body volume (C B ) also refers to a galvanic resistor that creates a capacitance to ground or any other reference potential. A test lead with insulated wiring may also be included.

[0036] The AC voltage (V O ) is connected to an external ground 128 (e.g., neutral). The non-contact voltage measurement system 102 itself also has a capacitance to ground 128, which is primarily the human body capacitance (C B ) Capacity C O and C B Both of these make the conductive loop is generated, and the voltage inside the loop is proportional to the signal current (I O ) is generated. O ) is the AC voltage signal (V O) is generated by the non-contact voltage The human body capacitance (C B ) via The current signal (I O ) is the conductive sensor of the non-contact voltage measurement system 102. The distance between the conductive sensor 126 and the insulated conductor 106 under test, the particular shape of the conductive sensor 126, and the size and voltage level (V O ) depends on

[0037] Signal current (I O ) and the associated coupling capacitance (C O To compensate for the variation in the signal voltage frequency (f), the non-contact voltage measurement system 102 includes a common-mode reference voltage source 130 that is O ) and a different reference frequency (f R ) with an AC reference voltage (V R )

[0038] To reduce or avoid stray currents, at least a portion of the non-contact voltage measurement system 102 may be surrounded by a conductive internal grounded guard or screen 132 that directs most of the current through the conductive sensor 126, which is coupled to a coupling capacitor (C O ) is formed by the conductor 122 of the insulated conductor 106. The internal ground guard 132 is , can be formed from any suitable conductive material (e.g., copper) and can be solid (e.g., foil) or can have one or more openings (e.g., mesh).

[0039] Additionally, to avoid current flow between the internal ground guard 132 and the external ground 128, the non-contact voltage measurement system 102 includes a conductive reference shield 134. The reference shield 134 may be formed from any suitable conductive material (e.g., copper) and may be solid (e.g., foil) or may have one or more openings (e.g., mesh). A common mode reference voltage source 130 is electrically coupled between the reference shield 134 and the internal ground guard 132, thereby providing a reference voltage (V R ) and the reference frequency (f R ) is generated. Such an AC reference voltage (V R ) causes an additional reference current (IR) to flow through the coupling capacitor (C O ) and human body capacitor (C B )

[0040] An internal ground guard 132 that surrounds at least a portion of the conductive sensor 126 protects the conductive sensor from an AC reference voltage (V) that would cause undesirable deviations in the reference current (IR) between the conductive sensor 126 and the reference shield 134. R ) against the direct effects of Additionally, the internal ground guard 132 is an internal electronic ground 138 of the non-contact voltage measurement system 102. In at least some implementations, the internal ground guard 132 also provides an AC reference voltage (V R In order to avoid this, the electronic components of the non-contact voltage measurement system 102 It also surrounds part or all of

[0041] As described above, the reference shield 134 couples the reference signal to the input AC voltage signal (V O ) Insert on top and a second function of minimizing the guard 132 to ground 128 capacitance. In at least some implementations, the reference shield 134 surrounds some or all of the housing 108 of the non-contact voltage measurement system 102. In such implementations, some or all of the electronics have a reference common mode signal that also generates a reference current (IR) between the conductive sensor 126 and the conductor 122 in the insulated conductor 106. In at least some implementations, the only gap in the reference shield 134 can be an opening for the conductive sensor 126, which allows the conductive sensor to be positioned in close proximity to the insulated conductor 106 during operation of the non-contact voltage measurement system 102.

[0042] The internal ground guard 132 and the reference shield 134 can provide a dual layer screen around the housing 108 (see FIGS. 1A and 1B) of the non-contact voltage measurement system 102. The reference shield 134 can be disposed on an exterior surface of the housing 108, and the internal ground guard 132 can function as an internal shield or guard. 6 is shielded by guard 132 against a reference shield 134, and any reference current flow is detected by a coupling capacitor (C O ) It is becoming possible to achieve this.

[0043] A guard 132 around the sensor 126 also reduces the stray effects of adjacent electrical wires close to the sensor.

[0044] 2, the non-contact voltage measurement system 102 can include an input amplifier 136 that operates as an inverting current-to-voltage converter. The input amplifier 136 has a non-inverting terminal electrically coupled to an internal ground guard 132 that serves as an internal ground 138 of the non-contact voltage measurement system 102. An inverting terminal of the input amplifier 136 can be electrically coupled to the conductive sensor 126. A feedback circuit 137 (e.g., a feedback resistor) can also be coupled between the inverting terminal and an output terminal of the input amplifier 136 to provide feedback and appropriate gain for conditioning the input signal.

[0045] The input amplifier 136 receives the signal current (I O ) and reference current (I R ) from the conductive sensor 126 and converts the received current into a sensor current voltage signal indicative of the conductive sensor current at an output terminal of the input amplifier. For example, the sensor current voltage signal may be an analog voltage. The analog voltage may be provided to a signal processing module 140, which processes the sensor current voltage signal as discussed further below to obtain an AC voltage (V O The signal processing module 140 determines It may include any combination of digital and / or analog circuitry.

[0046] The non-contact voltage measurement system 102 also measures the determined AC voltage (V O ) or A user interface 142 (eg, a display) communicatively coupled to the signal processing module 140 for communicating via an interface to an operator 104 of the non-contact voltage measurement system may also be included.

[0047] 3 is a block diagram of a non-contact voltage measurement system 300 illustrating various signal processing components of the non-contact voltage measurement system. FIG. 4 is a more detailed diagram of the non-contact voltage measurement system 300 of FIG.

[0048] The non-contact voltage measurement system 300 can be similar or identical to the non-contact voltage measurement system 102 discussed above. Accordingly, similar or identical components are designated with the same reference numerals. As shown, the input amplifier 136 receives the input current (I O +I R ) into a sensor current voltage signal indicative of the input current. The sensor current voltage signal is converted to digital form using an analog-to-digital converter (ADC) 302.

[0049] The AC voltage in the wire 122 (V O ) is calculated by the AC reference voltage (V R )

number

[0050] AC voltage (V O ) is the signal having the index "O" related to the common mode reference voltage source 130 The "O" signal has characteristics such as frequency that are different from the signal having an index "R" related to the frequency of the "O" signal. In the implementation of FIG. 4, digital processing can be used to separate the magnitudes of the signals having different frequencies, such as a circuit performing a fast Fourier transform (FFT) algorithm 306. In the implementation of FIG. 5 discussed below, analog electronic filters can also be used to separate the "O" signal characteristics (e.g., magnitude, frequency) from the "R" signal characteristics.

[0051] Current (I O ) and (I R ) is the coupling capacitor (C O ) for frequency (f O ) and (f R ) depends on the coupling capacitor (C O ) and human body capacity (C B ) flows through The current flowing through the conductor 122 under test is proportional to the frequency, and therefore the AC voltage (V O ) around Wave number (f O ) to find the signal frequency (f O ) for the reference frequency (f R Determine the ratio of This ratio is utilized in equation (1) above, or is already known since the reference frequency is generated by the system itself.

[0052] Input current (I O +I R After the frequency (f) is conditioned by the input amplifier 136 and digitized by the ADC 302, the frequency content of the digital sensor current voltage signal can be determined by representing the signal in the frequency domain using an FFT 306. O ) and (f R ) are measured, the current (I O ) and (I R ) basic size of FF From T 306, the frequency bin for the calculation can be determined.

[0053] Current (I R ) and / or current (I O ) may vary as a function of the distance between a reference signal sensor or electrode (e.g., electrode 126) and the conductor 122 of the insulated wire body 106. Thus, the system may R ) and / or current (I O) to the expected respective currents to determine the distance between the reference signal sensor or electrode and the conductor 122. Because the insulated wire 106 can be positioned (e.g., via an adjustable clamp assembly) proximate the reference signal sensor or electrode during measurement, the distance between the reference signal sensor and the conductor 122 of the insulated wire 106 is approximately equal to the thickness of the insulating layer 124. As discussed below, a position feedback sensor operably coupled to the adjustable clamp assembly provides the overall diameter of the insulated wire 106. Thus, using the determined overall diameter of the insulated wire and the determined thickness of the insulating layer 124, the system can accurately determine the diameter or gauge of the inner conductor 122 of the insulated wire 106. This information, along with the magnetic field measured by the magnetic field sensor, may be used by the system to accurately determine the magnitude of the current flowing through the inner conductor 122 of the insulated wire 106.

[0054] Next, as indicated by block 308, R , 1 and I O ,1 and the specified current (I R ) and (I O ) of the fundamental harmonic at the determined frequency (f O ) and (f R ) by The harmonics (V O ) added inside wire 122 The original fundamental or RMS voltage measured can then be calculated, which is done by calculating the square root of the sum of the squared harmonics, and can be shown to the user on the display 312.

[0055] Coupling capacitor (C O ) is the distance between the insulated conductor 106 and the conductive sensor 126, and In addition, depending on the particular shape and dimensions of the sensor 126, the human body capacitance (C B ), for example, is approximately 20 It can have a capacitance value of pF to 200 pF.

[0056] From equation (1) above, the AC reference voltage (V R ) is the magnitude of a similar current as the signal current (I O ) and reference current (I R ) to be achieved Therefore, the AC voltage in conductor 122 (V O ) does not have to be in the same range. C Reference Voltage (V R ) is relatively high, so the reference frequency (f R ) can be relatively low (e.g., less than 5 V). R ) can be chosen to be 3 kHz, which is the fraction of the signal frequency (f O ) with a typical 120 VRMS AC voltage (V O ) is 50 times higher than the AC reference voltage (V R ) is the signal current (I O ) and the same reference current (I R ) In general, the reference frequency (f R ) to the signal frequency (f O ), then the AC reference voltage (V R ) expresses the same uncertainty as I R and I0 are in the same range as each other to achieve R ) and (I O ) in the wire 122 to generate an AC voltage (V O )(1 / N ) times the value.

[0057] Any suitable signal generator may be used to generate a reference frequency (f R ) with an AC reference voltage (V R) can be generated. In the embodiment shown in FIG. 3, a sigma-delta digital-to-analog converter (Σ-Δ DAC) 310 is used. The Σ-Δ DAC 310 uses the bitstream to generate a defined reference frequency (f R ) and AC reference voltage (V R ) In at least some implementations, the Σ-Δ DAC 310 can generate a waveform that is in phase with the window of the FFT 306 to reduce jitter.

[0058] In at least some implementations, the ADC 302 may have 14-bit resolution. In operation, the ADC 302 generates 2 x 100 ms samples that are ready for processing by the FFT 306. n samples (1024) (10Hz bins for FFT 306) The output from the input amplifier 136 may be sampled at a sampling frequency of 10.24 kHz for a nominal 50 Hz input signal to provide a 60 Hz input signal. For a 60 Hz input signal, the sampling frequency may be, for example, 12.288 kHz to obtain the same number of samples per cycle. The sampling frequency of the ADC 302 may be set to a reference frequency (f R ) complete cycles. For example, the input signal frequency can be It can be in the range of 40 to 70Hz. AC voltage (V O ) depending on the measured frequency In order to suppress the phase shift jitter caused by the incomplete signal period captured within the aggregation interval, the FFT 306 is used and the Hanning window function is used for further calculation. O ) bins can be determined.

[0059] In one embodiment, the common mode reference voltage source 130 generates a reference frequency (f R ) with an AC reference voltage (V R), which is between the 40th and 41st harmonics for a 60 Hz signal and between the 48th and 49th harmonics for a 50 Hz signal. O ) is not a harmonic of Quasi-frequency (f R ) with an AC reference voltage (V R ) to supply an AC voltage (V O ) are less likely to affect the reference current (IR) measurement.

[0060] In at least some implementations, the reference frequency (f R ) is the AC voltage in the conductor 122 under test (V O ) are least likely to be affected by harmonics. As an example, the common mode reference voltage source 130 may be selected to have a reference current (I R ) exceeds the boundary, this is the conductive sensor 12 6 may be close to the conductor under test 122. Measurements (e.g., 100 ms measurements) may be taken with the common mode reference voltage source 130 powered down to detect signal harmonics at a few (e.g., three, five) candidate reference frequencies. The AC voltage (V O ) at the candidate reference frequencies. Candidate reference frequency is AC voltage (V O ) is likely to be least affected by signal harmonics. Then, the reference frequency (f R ) is the identified candidate reference frequency The reference frequency can be set to a number between 2419 Hz and 2679 Hz. This switching of the reference frequency can avoid or reduce the impact of possible reference frequency components in the signal spectrum, but it can increase the measured reference signal and reduce accuracy, which can lead to unstable results. Other frequencies of 2419 Hz with the same characteristics include, for example, 2344 Hz and 2679 Hz.

[0061] 5 is a block diagram of a signal processor 500 of a non-contact voltage measurement system that implements electronic filtering. The signal processor 500 receives the conductive sensor 126 current (I O +I R ) may receive a sensor current voltage signal that is proportional to the

[0062] As mentioned above, the signal current (I O ) is the reference current (I R ) and the signal current (I O ) to the reference current (I R ), the signal processing unit 500 is O ) to transmit the reference current (I R ) and a first filter 502 that operates to reject The filtered signal may then be rectified by a first rectifier 504 and digitized by a first ADC 506. The digitized signal may be provided to a suitable processor 508 for use in calculations, as discussed above. Similarly, the reference current (I R ) to the signal current (I O ), the signal processing section 500 uses a reference current (I R ) to transmit the signal current (I O) may include a second filter 510 that operates to reject the first ADC 512. The filtered signal may then be rectified by a second rectifier 512 and digitized by a second ADC 514. The digitized signal may be provided to a suitable processor 508 for use in the calculations. The first and second filters 502 and 510 may be any suitable analog filters and may each include several discrete components (e.g., capacitors, inductors).

[0063] FIG. 6 shows a common-mode reference voltage source 130, a human body capacitance (C B ), coupling capacitor (C O 1 is a schematic circuit diagram of portions of a non-contact voltage measurement system, such as any of the non-contact voltage measurement systems discussed above, showing the loop formed by the external ground 128, the electrical wire 122, and the internal ground 138.

[0064] 7A is a schematic diagram of a non-contact voltage measurement system 102 showing various leakage and stray capacitances. In general, the elimination of the effects of different stray capacitances in a system (e.g., sensor 126) cannot be completely achieved by special sensor design and screening techniques, even with advanced shielding techniques. As mentioned above, implementations of the present disclosure utilize a common-mode reference voltage source 130 to provide a common-mode reference voltage for the measured signal frequency (f O ) and a different reference frequency (f R ) to compensate for stray capacitance in the system.

[0065] In particular, the coupling capacitor (C O ), FIG. 7A also shows the human body capacitance (C B ), capacity (C X ), Capacity (C SENS-REF ) and capacity (C G ) indicates the human body capacity (C B ) is the coupling capacitor (C O ) in series with the human body capacitance (C B ) is the coupling capacitor (CO ), so the human body capacitance (C B ) is the current (I O +I R ) size It only affects the ratio of current (I O / I R ) is not affected.

[0066] As shown in FIG. 7A and FIG. 8, the capacitance (C X ) is connected to the conductive sensor 126 and the external ground 128 The coupling capacitor (C O ) is a wire 122 and a sensor 126 The capacitance between the sensor 126 and the external ground 128 (C X ) is also available. X ) represents the capacitive voltage divider effect on the signal current (I O ) and, as a result, the AC voltage (V O ) may result in a lower voltage measurement. Therefore, X ) is the current (I O +I R ) is reduced in magnitude. However, the reference current (I R ) are divided in equal proportions, Therefore, the stray capacitance (C X ) is also corrected, so the ratio (I O / I R ) is not affected. Also, To avoid internal current flow outside the non-contact voltage measurement system, in at least some implementations, as described above, the entire measurement system, except for the sensing area, is shielded from the external environment by a reference shield 134 and connected to the output of a common mode reference voltage source 130 to generate a reference current (I R ) can be generated.

[0067] As shown in FIG. 7A, the capacitance (C SENS-REF ) is the remaining capacitance between the reference shield 134 and the conductive sensor 126.SENS-REF ) is the sensor current (I O +I R ), the AC voltage in the wire 106 (V O ) is not measured. cause.

[0068] As shown in FIG. 7A and FIG. 9A, the capacitance (C G ) is connected to the internal ground 138 and the external ground 128 This is the capacitance between the two, i.e. the reference potential. G ) is the reference current (I R ) which reduces the reference current. Therefore, the capacitance (C G ) causes the AC current in the wire 106 to Pressure (V O ) the calculated increase in capacity (C G See FIG. 9B, which shows the effect of capacitance (C G ) shows different effects for IR and I O Therefore, the ratio I O / I R Affects.

number

[0069] As can be seen from the above equations (2)-(5), the ratio I O / I R is C B / C G It depends on the capacity C G The reference screen covers the entire housing of the non-contact voltage measurement system 102 and the periphery of the sensor. It is much smaller when it is in contact with the ground.

[0070] FIG. 7B shows the inverted reference signal (-V R ) and a configuration for coupling the inverted reference signal to the sensor 126. By using and, the reference voltage (V R ) on sensor 126. 7C shows an example sensor configuration including inverted reference signal compensation.

[0071] In FIG. 7B, an adjustable inverting amplifier 141 is connected to a reference voltage (+V R ) on the sensor To compensate for the effect of R ) to the sensor 126 This is achieved by using a capacitive coupling (C C ) by This can be achieved by capacitive coupling (C C ) is a wire positioned close to the sensor , a screen, a shield, etc. The correction, in such an example, is based on a reference voltage (V R ) is likely to have the greatest effect on sensor 126. This can be particularly advantageous when the insulated conductor 106 has a relatively small diameter.

[0072] 7C illustrates an exemplary sensor configuration 139 used in an implementation that performs the reference signal correction described above. The sensor configuration 139 includes a sensor 139a and an insulating layer 139b (e.g., , Kapton® tape), an internal ground guard 139c, and an inverted reference signal layer 139d (-V R ), an insulating layer 139e, and a reference signal layer 139f (+V R ) and

[0073] 10 is a perspective view of an exemplary sensor and guard assembly 1000 for a non-contact voltage measurement system, such as any of the non-contact voltage measurement systems discussed above. In this embodiment, the sensor and guard assembly 1000 includes a conductive sensor 1002, an internal ground guard 1004, and an insulating layer 1006 disposed between the sensor and the internal ground guard. In general, the sensor assembly 1000 has good coupling capacitance (C O ) Sensor 10 1002 and the wire under test, and must suppress capacitance to other adjacent wires and capacitance to external ground. The sensor assembly 1000 also reduces the capacitance (C SENS-REF ) also needs to be kept to a minimum.

[0074] As a simple example, the sensor 1002, guard 1004 and insulating layer 1006 may each comprise a strip of foil. The guard 1004 may be bonded to a carrier (see FIG. 11), the insulating layer 1006 (e.g., Kapton® tape) may be bonded to the guard, and the sensor 1002 may be bonded to the insulating layer.

[0075] 11 shows a cross-sectional view of an embodiment of a sensor implementation of a probe or front end 1100 of a non-contact voltage measurement system, which includes a housing layer 1102 (e.g., plastic) that covers the sensor assembly 1000 to avoid direct galvanic contact between the sensor assembly and any object. The front end 1100 can be similar or identical to the front end 112 of the non-contact voltage measurement system 102 shown in FIGS. 1A and 1B. In this example, the sensor assembly 1000, including the sensor 1002, guard 1004, and insulating layer 1006, surrounds insulated wires of different diameters and provides a coupling capacitance (C O ) and provides better shielding from adjacent conductive objects by the guard. The casing is shaped in a "U" or "V" to allow for shielding.

[0076] In the embodiment shown in FIG. 11, the sensor assembly 1000 is shaped to accommodate insulated wires of various diameters, such as an insulated wire 1104 having a relatively large diameter or an insulated wire 1106 having a relatively small diameter. In each case, the sensor assembly 1000 substantially surrounds the wire when it is positioned within the recessed portion 1108 of the front end 1100. The walls of the front end 1100 that define the recessed portion 1108 and are positioned between the sensor assembly 1000 and the wire under test can be relatively thin (e.g., 1 mm) to provide galvanic isolation while still allowing suitable capacitive coupling. Due to the "V" shape of the recessed portion 1108, the thicker wire 1104 has more clearance than the thinner wire 1106 to reduce the wide range of coupling capacitance and also reduce environmental capacitance to reduce independence of wire diameter.

[0077] 12 is an elevational view of an arcuate shaped front end 1200 of a non-contact voltage measurement system. Front end 1200 includes a recessed portion 1202 defined by first and second extension portions 1204 and 1206. Recessed portion 1202 includes a relatively large upper arcuate shaped portion 1208 that receives an insulated wire 1210 having a relatively large diameter. Recessed portion 1202 also includes a relatively smaller lower arcuate shaped portion 1212 below portion 1208 that receives an insulated wire 1214 having a relatively small diameter. Sensor assembly 1216, which may be similar to sensor assembly 1000 shown in FIG. 10, and is covered by portions 1208 and 1212, may have a shape that substantially matches the arcuate shaped portions 1208 and 1212, such that sensor assembly 1216 substantially surrounds a wire having a relatively large diameter (e.g., wire 1210) and a wire having a relatively small diameter (e.g., wire 1214).

[0078] 13 is a perspective view of a cylindrical front end 1300 of a non-contact voltage measurement system. In this embodiment, the front end 1300 includes a cylindrical internal ground guard 1302 having side walls 1304 and a front face 1306 that can be positioned adjacent to the wire under test. The front face 1306 of the internal ground guard 1302 includes a central opening 1308. A coupling capacitor (C O ) A conductive sensor 1310 formed with the wire under test is recessed behind an opening 1308 in the internal ground guard 1302 to avoid capacitive coupling with adjacent objects. The sensor 1310 may be recessed (e.g., 3 mm) from the front surface 1306 of the internal ground guard 1302, for example.

[0079] A sidewall 1304 of the internal ground guard 1302 may be surrounded by a cylindrical reference shield 1312, which is isolated from the internal ground guard by an insulating layer 1314. A common mode reference voltage source (e.g., voltage source 130) may be connected between the internal guard ground 1302 and the reference shield 1312 to provide the functionality discussed above.

[0080] 14A and 14B show a top view of a front end 1400 of a non-contact voltage measurement system, and FIG. 15 shows a perspective view of a portion of the front end. In this embodiment, the front end 1400 includes an internal ground guard 1402 that includes a front surface 1404 against which a wire under test 1406 (FIG. 15) can be positioned. The front surface 1404 includes an edge 1407, in this case rectangular, that defines an opening 1408 in the front surface. This small, long rectangular opening accommodates the wire shape seen from the side and that has a longer but thinner shape. This again reduces the effect on adjacent wires and also greatly reduces the environmental capacitance associated with the sensor. This results in high accuracy independent of wire diameter. The coupling capacitor (C O ) with the wire under test, , 3 mm) recessed behind an opening 1408 in the front surface 1404 of the inner guard ground 1402 .

[0081] The internal ground guard 1402 also includes side walls 1412 and 1414 that extend forward (towards the wire under test) from the lateral edges of the front surface 1404. The side walls reduce sensor stray capacitance and direct reference signal coupling. The internal ground guard 1402 may also include a conductive guard ring clamp 1416 including a first clamp arm 1416A and a second clamp arm 1416B. The clamp arms 1416A and 1416B may be selectively moved to an open position shown in FIG. 14B to allow the wire under test to be positioned adjacent the front surface 1404 of the internal ground guard 1402. Once the wire is in place, the clamp arms 1416A and 1416B may be selectively moved to a closed position shown in FIG. 14A to provide shielding around the sensor 1410 from capacitance with the external environment (e.g., nearby conductors, nearby objects). When in the closed position, the guard ring clamp 1416 may be substantially in the shape of a cylinder, for example, with a height extending above and below the sensor 1410. The clamp arms 1416A and 1416B may be selectively movable using any suitable manual or automatic actuation subsystem 1418. For example, the clamp arms 1416A and 1416B may be biased toward the closed position ( FIG. 14A ) by a spring or other biasing mechanism that serves as the actuation system 1418, such that an operator can overcome the bias to move the clamp arms to an open position ( FIG. 14B ) to position the wire under test adjacent the front surface 1404 of the internal ground guard 1402.

[0082] Capacitive divider type non-contact voltage measurement system The subject matter discussed below utilizes a capacitive divider type voltage sensor or system to measure the AC voltage across an insulated conductor (e.g., insulated wire) through a galvanic connection between the conductor and a test electrode or probe. The present invention relates to a system and method for measuring an insulated conductor without requiring a galvanic connection to the insulated conductor. Implementations disclosed in this section may be referred to herein as "capacitive divider voltage sensors" or systems. Generally, a non-contact voltage measurement system is provided that includes a variable capacitance subsystem that operates to generate a variable capacitive voltage between the insulated conductor under test and ground. During the measurement, the non-contact voltage measurement system varies the capacitance of the variable capacitance subsystem to vary the impedance of a capacitive divider circuit between the insulated conductor under test and ground. By performing two (or three) measurements sequentially across the variable capacitance subsystem, the AC voltage of the insulated conductor can be determined without requiring a galvanic connection to the insulated conductor. Such a system that does not require a galvanic connection is referred to herein as "non-contact." As used herein, "electrically coupled" includes both direct and indirect electrical coupling, unless otherwise specified.

[0083] FIG. 16 is a schematic diagram of an environment 2100 in which a non-contact voltage measurement system 2102 of the present disclosure can be used by an operator 2104 to measure an AC voltage 2106 present in an insulated electrical wire without requiring galvanic contact between the non-contact voltage measurement system and the wire 2106. FIG. 17 is a top view of the non-contact voltage measurement system 2102 of FIG. 16. The non-contact voltage measurement system 2102 includes a housing or body 2108 that includes a gripping portion or end 2110 and a probe portion or end 2112 opposite the gripping portion. The housing 2108 can also include a user interface 2114 to facilitate user interaction with the non-contact voltage measurement system 2102. The user interface 2114 can include any number of inputs (e.g., buttons, dials, switches, touch sensors) and any number of outputs (e.g., displays, LEDs, speakers, buzzers).

[0084] 17, the probe portion or end 2112 can include a recessed portion 2116 defined by first and second extension portions 2118 and 2120. The recessed portion 2116 receives the insulated wire 2106. The insulated wire 2106 includes a conductor 2122 and an insulator 2124 surrounding the conductor 2122. The recessed portion 2116 can include a sensor or electrode 2126 that is placed proximate or substantially proximate to the insulator 2124 of the insulated wire 2106 when the insulated wire is positioned within the recessed portion 2116 of the non-contact voltage measurement system 2102.

[0085] 16 , in use, an operator 2104 can grasp the gripping portion 2110 of the housing 2108 and place the probe portion 2112 in proximity to the insulated electrical wire 2106 such that the non-contact voltage measurement system 2102 can accurately measure the AC voltage present in the wire relative to ground (or another reference node). Although the probe end or end 2112 is shown as having a recessed portion 2116, in other implementations the probe portion 2112 can be configured in a different manner. For example, in at least some implementations the probe portion 2112 can include a selectively movable clamp, hook, flat or arcuate surface that includes a sensor, or other type of interface that allows the sensor of the non-contact voltage measurement system 2102 to be positioned in proximity to the insulated electrical wire 2106.

[0086] As discussed further below, in at least some implementations, the non-contact voltage measurement system 2102 measures the body capacitance (C B ) to measure AC voltage The particular system and method used by the non-contact voltage measurement system 2102 to measure AC voltage is discussed below with reference to Figures 18-22.

[0087] 18 is a high level block diagram of a non-contact voltage measurement system 2300. The measurement system 2300 can be similar or identical to the non-contact voltage measurement system 2102 of Figures 16 and 17 discussed above.

[0088] The non-contact voltage measurement system 2300 includes a conductive sensor or electrode 2302 that is sized, dimensioned, and positioned to be proximate the insulated wire 2106 when the operator 2104 positions the probe portion or end 2112 (FIG. 16) proximate the wire. The sensor 2302 may be similar or identical to, for example, the sensor 2126 of FIG. 17. When the non-contact voltage measurement system 2300 is positioned proximate the insulated wire 2106 with the sensor 2302 in proximity to the wire, the sensor capacitively couples with the insulated wire. In other words, the conductive portion of the sensor 2302 capacitively couples with the sensor capacitor (C S 17 ), and an insulated wire 2106 ( ) conductor 2122 comprises the other half of the sensor capacitor. In at least some implementations, the sensor 2302 can be designed such that the side of the sensor that faces the insulated wire 2106 is more sensitive to electromagnetic fields than the other side of the sensor that does not face the insulated wire.

[0089] The non-contact voltage measurement system 2300 also includes a variable capacitance subsystem 2304 electrically coupled to the conductive sensor 2302. The variable capacitance subsystem 2304 is configured to have a capacitance that is proportional to at least a first capacitance value (C1) and a second capacitance value (C2), where the second capacitance value (C2) is different from the first capacitance value (C1). In at least some implementations, the capacitance value is selectively variable between two capacitance values ​​(C1 and C2). In an example, the variable capacitance subsystem 2304 can be controlled to selectively have a capacitance value that is variable between at least a first capacitance value (C1), a second capacitance value (C2), and a third capacitance value (C3), where each of the first, second, and third capacitance values ​​are different from one another. As discussed further below, variable capacitance subsystem 2304 is used to vary the capacitance of a series capacitive circuit that extends from insulated wire 2106 through non-contact voltage measurement system 2300 to ground 2128 or other reference node.

[0090] In at least some implementations, at least one of the capacitance values ​​(e.g., capacitance value C1) may be selectively variable to accommodate different values ​​of input signal and input capacitance. For example, system 2300 can determine that an input signal is too large or too small for accurate measurement, and can selectively adjust one or more of the capacitance values ​​so that an accurate signal measurement can be obtained. Thus, one or more of the capacitance values ​​(e.g., C1) can be adjusted to a desired capacitance suitable for a particular input signal and input capacitance. This can be implemented using a number of physical capacitors that can be selectively coupled to obtain a quantitative value.

[0091] The non-contact voltage measurement system 2300 also includes a voltage measurement subsystem 2306 that operates to sense a voltage or a signal indicative of a voltage across the variable capacitance subsystem 2304. In at least some implementations, the voltage measurement subsystem 2306 can include an analog-to-digital converter (ADC) that converts an analog voltage signal to a digital signal. For example, the voltage measurement subsystem 2306 can be a very It may include an ADC having a relatively high effective resolution, such as 20 bits or more (e.g., 22 bits) resolution, which facilitates accurate measurements. In at least some implementations, the voltage measurement subsystem 2306 may include conditioning circuitry (e.g., one or more amplifiers and / or filters) that buffers, shapes, and / or amplifies the detected voltage from the variable capacitance subsystem 2304 before converting the signal to a digital form using the ADC.

[0092] The non-contact voltage measurement system 2300 can also include a controller 2308 communicatively coupled to the voltage measurement subsystem 2306 and the variable capacitance subsystem 2304. The controller 2308 can be any suitable hardware, software, or combination thereof. As an example, the controller 2308 can include one or more processors and one or more non-transitory process-readable storage media communicatively coupled to the one or more processors. The non-transitory process-readable storage media can store instructions and / or data that, when executed by the one or more processors, cause the one or more processors to perform functionality discussed herein (e.g., measure the AC voltage in the insulated wire 2106).

[0093] The control device 2308 may include one or more central processing units (CPUs), digital signal processors (DSPs), or specialized application-specific integrated circuit (ASIC), field Field programmable gate array (FPGA), program programmable logic controller (PLC), artificial neural network The controller 2308 may include any type of processing unit, such as a network circuit or system, or any other logical component. The non-transitory process readable storage medium coupled to the controller 2308 may include any type of non-transitory volatile and / or non-volatile memory.

[0094] The non-contact voltage measurement system 2300 may also include a user interface 2310 communicatively coupled to the controller 2308. The user interface 2310 may include any number of inputs (e.g., buttons, dials, switches, touch sensors) and any number of outputs (e.g., displays, LEDs, speakers, buzzers). In at least some implementations, the controller 2308 and / or the user interface 2310 may include one or more wired and / or wireless communication interfaces (e.g., USB, Bluetooth, WiFi) that enable data and / or instructions to be communicated between the non-contact voltage measurement system 2300 and one or more external devices.

[0095] In operation, the operator 2104 connects the sensor capacitor C S To form a sensor The non-contact voltage measurement system 2300 can be positioned proximate to the insulated wire 2106 such that the sensor 2302 is capacitively coupled to the wire. When the sensor 2302 is so positioned, the controller 2308 can cause the variable capacitance subsystem 2304 to have different capacitance values ​​and measurements can be taken from the voltage measurement subsystem 2306 at each of the different capacitance values. The controller 2308 can then determine the magnitude of the AC voltage present in the insulated wire 2106 based on the measurements taken and present the results to the operator 2104 via the user interface 2310. Further details regarding specific implementations of the non-contact voltage measurement system 2300 are discussed below with reference to FIGS. 19-21.

[0096] 19 is a schematic diagram of a non-contact voltage measurement system 2400 including a variable capacitance subsystem 2402 that utilizes two capacitors designated capacitors 2401 and 2403. Capacitors 2401 and 2403 can have the same or different capacitance values ​​as each other. As a non-limiting example, capacitors 2401 and 2403 can each have a capacitance value of 1000 picofarads (pF). As another example, capacitor 2401 can have a capacitance value of 1000 pF and capacitor 2403 can have a capacitance value of 2000 pF.

[0097] The variable capacitance subsystem 2402 includes a first capacitive subsystem node 2404 and a second capacitive subsystem node 2406. The capacitor 2401 is electrically coupled between the first capacitive subsystem node 2404 and the second capacitive subsystem node 2406. The first capacitive subsystem node 2404 is further electrically coupled to a conductive sensor 2408, which is similar to the contactless capacitive sensor of FIGS. 17 and 18 discussed above, respectively. The conductive sensor 2408 may be similar or identical to the conductive sensors 2126 and 2302 of the non-contact voltage measurement systems 2102 and 2300. As discussed above, when the non-contact voltage measurement system 2400 is positioned near the insulated wire 2106, the conductive sensor 2408 detects a voltage across the sensor capacitor C S 17, the conductor 2122 of the wire 2106 forms one half of the sensor Capacitor C S It forms the other half of the.

[0098] Variable capacitance subsystem 2402 also includes a switch S1 that operates to selectively electrically couple capacitor 2403 in parallel with capacitor 2401. By selectively controlling the first capacitance subsystem node 2404 and the second capacitance subsystem node S1, The capacitance value between the capacitance subsystem node 2406 of the variable capacitance subsystem 2402 is selectively variable between the capacitance value of capacitor 2401 and the sum of the capacitance values ​​of capacitors 2401 and 2403. If capacitors 2401 and 2403 have the same capacitance value (e.g., 1000 pF), then the capacitance of the variable capacitance subsystem 2402 when switch S1 is closed is twice the capacitance of the variable capacitance subsystem 2402 when switch S1 is open (e.g., 2000 pF vs. 1000 pF).

[0099] The second capacitance subsystem node 2406 is the human body capacitance C B Electrical to ground 2128 via The human body capacitance C B While the non-contact voltage measurement system 2400 is in operation, is the capacitance of the operator 2104 (FIGS. 16 and 17) that holds the body. In general, the operator's body can be modeled as a conductor covered by a thin insulator to ground 2128. Typically, the human body capacitance C B Depending on various factors, it can range from tens to as low as hundreds of picofarads. In at least some implementations, the body capacitance C B Rather than utilizing the second capacitance subsystem node 2406, The touch voltage measurement system 2400 may optionally be electrically coupled to ground 2128 via a suitable electrical connection between the touch voltage measurement system 2400 and ground.

[0100] A controller 2308 is coupled to selectively control the operation of switch S1. The capacitance of the variable capacitance subsystem 2402 is then set to C1 or C2. In this embodiment, the capacitance C1 is the capacitance of the capacitor 2401. The capacitance C2 is equal to the sum of the capacitances of the capacitors 2401 and 2403. In other embodiments, different capacitance values ​​C1 and C2 in the variable capacitive subsystem 2402 can be selectively achieved depending on the configuration of the capacitor and one or more switches between the first capacitive subsystem node 2404 and the second capacitive subsystem node 2406.

[0101] The non-contact voltage measurement system 2400 also includes an ADC 2410 electrically coupled to the first capacitive subsystem node 2404 and the second capacitive subsystem node 2406 . The ADC 2410 is communicatively coupled to the controller 2308 via a suitable interface (e.g., a synchronous serial interface (SSI)). The ADC 2410 operates to convert the analog voltage between the first capacitive subsystem node 2404 and the second capacitive subsystem node 2406 to a digital signal and provide the digital signal to the controller 2308. In at least some implementations, the ADC 2410 may have a relatively high effective resolution, such as 20 or more bits of resolution (e.g., 22 bits, 24 bits, 30 bits). Although not shown for clarity, the ADC 2410 may include or be coupled to conditioning circuitry (e.g., one or more amplifiers and / or filters) that buffers, shapes, and / or amplifies the detected voltage from the variable capacitive subsystem 2402 before converting the signal to a digital form. Additionally, the controller 2308 and the ADC Although 2410 is shown generally as separate components, in at least some implementations, some or all of the functionality may be implemented as a single system or component (e.g., a single integrated The circuit may be combined into a

[0102] The sensor and wires are connected to the sensor capacitor C S The sensor 2408 is connected to a wire To measure the AC voltage in the electrical line 2106 when positioned adjacent to the electrical line 2106, the controller 2308 first controls the variable capacitance subsystem 2402 to provide a first capacitance value C1 to the first capacitance subsystem 2402. The control device 2308 may include a first capacitive subsystem node 2404 and a second capacitive subsystem node 2406. For example, the control device 2308 may include such a switch by opening switch S1. This can be achieved such that the variable capacitance subsystem 2402 has a capacitance value equal to the capacitance of the capacitor 2401.

[0103] Next, while the variable capacitance subsystem 2402 has the first capacitance value C1, the controller 230 8 provides the ADC 2410 with a first voltage V between the first capacitive subsystem node 2404 and the second capacitive subsystem node 2406. M1 Such a voltage V M1 may be stored by the controller 2308 in a non-transitory process readable storage medium for subsequent use.

[0104] Next, the first voltage V M1 After obtaining the measurements, the controller 2308 controls the variable capacitance subsystem 2402 to calculate a second capacitance value C2 between the first capacitance subsystem node 2404 and the second capacitance For example, controller 2308 may have switch S2 in order to place capacitor 2403 in parallel with capacitor 2401. This can be accomplished by closing, so that variable capacitance subsystem 2402 has a capacitance value equal to the sum of the capacitance values ​​of capacitors 2401 and 2403 .

[0105] The variable capacitance subsystem 2402 has a second capacitance value C2, while the controller 2308 The ADC 2410 receives a second voltage V between the first capacitive subsystem node 2404 and the second capacitive subsystem node 2406. M2 can be captured or measured.

[0106] The controller 2308 then calculates the AC voltage in the insulated wire 2106 as a sensed first voltage VM1 , the detected second voltage V M2 , may be determined based at least in part on the first capacitance value C1 and the second capacitance value C2. An example process for determining the AC voltage in the insulated wire 2106 is discussed below with reference to FIG.

[0107] FIG. 20 shows a schematic circuit diagram of the non-contact voltage measurement system 2400 of FIG. 19. In this embodiment, the AC voltage on the insulated wire 2106 is supplied by an AC power source (V AC ) is a series capacitive circuit that is connected to an AC power source (V AC ) and the sensor capacitor C S and a measurement capacitance C, which has a capacitance value C1 or a capacitance value C2 depending on the state of switch S1. M and operator 2104 (FIG. 16 and Figure 17) Human body capacitance C B As discussed above, the ADC2410 is the capacitance of the variable capacitance subsystem 2402 at a first capacitance value (i.e., C M = C1) M1 across nodes 2404 and 2406, and the variable capacitance subsystem obtains a second capacitance value (i.e., C M = C2) M2 is acquired across nodes 2404 and 2406. The measured voltage V M is node 240 Voltage at 4 (V 404 ) and the voltage at node 2406 (V 406 ) (i.e., V M =V 404 ~V 406 ).

[0108] The current at node 2404 can be represented by the equation: I CS -I CM =0 (6) Current (I CS ) is given by the following formula:

number

number

[0109] Similarly, the current at node 2406 can be represented by the equation: I CM -I CB =0 (9) Current (I CB ) is given by the following formula:

number

[0110] Using equations (6) and (9) above, and V M =V 404 ~V 406 , V M can be expressed by the following formula:

number

[0111] As discussed above, the ADC 2410 detects that the variable capacitance system 2402 has a capacitance value C1. The first voltage measurement V M1 and the variable capacitance system 2402 has a capacitance value C2 The second voltage measurement V M2 Therefore, V M1 and V M2 can be expressed by the following formula:

number

[0112] Equations (13) and (14) express the AC voltage (V AC ) can be solved for, which is given by the following equation:

number

[0113] As can be seen from equation (15), the AC voltage (V AC ) is the known capacitances C1 and C2 (i.e., the ratio of capacitances C1 and C2) and the measured voltage V M1 and V M2 That is, the AC voltage in the insulated wire 2106 (V AC ) to obtain the sensor capacitor C S and human body capacity C B It is not necessary to determine the frequency of the AC voltage. Furthermore, it should be noted that the frequency of the AC voltage drops out of the equation, but the overall impedance of the system 2400 depends on the frequency and capacitance of the smallest capacitor in the circuit. For example, with a sensor capacitance C of 1 pF, which is the smallest capacitor in the circuit, S The impedance of the circuit is about 3.5GΩ at 50Hz. It is.

[0114] 21 is a schematic diagram of a non-contact voltage measurement system 2600 that includes a variable capacitance subsystem 2601 that utilizes three capacitors, namely capacitors 2602, 2604, and 2606. The non-contact voltage measurement system 2600 is similar or identical to the non-contact voltage measurement systems discussed above, so for brevity only the substantial differences will be discussed below.

[0115] The non-contact voltage measurement system 2600 includes a first capacitance subsystem node 2608 electrically coupled to the sensor 2408 and a body capacitance C B a second capacitive subsystem node 2610 electrically coupled to ground 2128 via In at least some implementations, the second capacitive subsystem node 2610 can optionally be directly electrically coupled to ground 2128 via a suitable electrical connection 2612 ("reference connection").

[0116] The capacitor 2602 is connected to the power supply 2606 via a switch S2 that is controllable by the controller 2308. The capacitor 2604 can be selectively coupled in series between the nodes 2608 and 2610 via a switch S3 that is controllable by the controller 2308. The capacitor 2606 can be selectively coupled in series between the node 2608 and a node 2610. The capacitor 2606 can be selectively coupled in series between the node 2608 and a node 2610 through a switch S4 that is controllable by the controller 2308. 23.08 and node 2610. In at least some implementations, the controller 2308 controls one of the switches S2, S3, and S4 at a time. Close and connect one of the capacitors in series between node 2608 and node 2610 at a time. In such an example, each of capacitors 2602, 2604, and 2606 can have a different capacitance value from each other. For example, capacitor 2602 can have a capacitance value of 1000 pF, capacitor 2604 can have a capacitance value of 2000 pF, and capacitor 2606 can have a capacitance value of 24000 pF. Generally, the capacitance values need to be selected such that they cause a relatively large variation in the measured voltage value when each of the capacitors is switched into the circuit.

[0117] The sensor and the wire form the sensor capacitor C S when the sensor 2408 is positioned near the wire 2106 to measure the AC voltage (V AC ) in wire 2106, the control device 2308 first causes the variable capacitance subsystem 2402 to have a first capacitance value C1 between the first capacitance subsystem node 2608 and the second capacitance subsystem node 2610 . For example, the control device 2308 can achieve this by closing switch S2 and opening switches S3 and S4, due to which the variable capacitance subsystem 2601 has a capacitance value equal to the capacitance of capacitor 2602.

[0118] Next, the variable capacitance subsystem 2402 has the first capacitance value C1, but the control device 23 08 can capture the first measured voltage V M1 between the first capacitance subsystem node 2608 and the second capacitance subsystem node 2610 by the ADC 2410. Such a voltage V M1 can then be stored by the control device 2308 in a non - transitory process - readable storage medium for subsequent use.

[0119] Next, the first voltage V M1After obtaining the measurements, the controller 2308 may then configure the variable capacitance subsystem 2601 to have a second capacitance value C2 associated with the first capacitance subsystem node 2608 and the second capacitance For example, the controller 2308 may do so by closing switch S3 and opening switches S2 and S4. can be achieved, which causes variable capacitance subsystem 2601 to have a capacitance value equal to that of capacitor 2604.

[0120] The variable capacitance subsystem 2601 has a second capacitance value C2, but the controller 2308 , the ADC 2410 receives the second measured voltage V M2 can be captured between the first capacitive subsystem node 2608 and the second capacitive subsystem node 2610.

[0121] Second voltage V M2 After obtaining the measurements, the controller 2308 controls the variable capacitance subsystem 2601 to provide a third capacitance value C3 to the first capacitance subsystem node 2608 and the second capacitance subsystem node 2609. For example, the controller 2308 may accomplish this by closing switch S4 and opening switches S2 and S3. 2606.

[0122] The variable capacitance subsystem 2601 has a third capacitance value C3, but the controller 2308 , the ADC 2410 receives the third measured voltage V M3 can be captured between the first capacitive subsystem node 2608 and the second capacitive subsystem node 2610.

[0123] The controller 2308 then determines the AC voltage (V AC ) to the first voltage V M1, the detected second voltage V M2 , the detected third voltage V M3 , the first capacitance value C1 , can be determined based at least in part on the second capacitance value C2 and the third capacitance value C3. AC An exemplary process for determining

[0124] When switch S2 is closed and switches S3 and S4 are open, AC voltage (V AC ) can be expressed by the following formula: V AC =I1(Z S +Z B +Z 602 ) (16) where I1 is the series winding current and Z S is the sensor capacitor C S The unknown impedance of Z B is the body capacitance C of the operator 2104 (FIGS. 16 and 17). B is the unknown impedance of Z 602 is the impedance of the capacitor 2602.

[0125] When switch S3 is closed and switches S2 and S4 are open, The AC voltage can be expressed by the following formula: V AC =I2(Z S +Z B +Z 604 ) (17) where I2 is the series current and Z S is the sensor capacitor C S The unknown impedance of Z B is the body capacitance C of the operator 2104 (FIGS. 16 and 17). B Unknown Inn Z 604 is the impedance of the capacitor 2604.

[0126] When switch S4 is closed and switches S2 and S3 are open, AC voltage (V AC ) can be expressed by the following formula: V AC =I3(Z S +Z B +Z 606 ) (18) where I3 is the series winding current and Z S is the sensor capacitor C S The unknown impedance of Z B is the body capacitance C of the operator 2104 (FIGS. 16 and 17). B is the unknown impedance of Z 606 is the impedance of the capacitor 2606.

[0127] Setting equations (16) and (17) equal to each other, Z S +Z B Solving for gives the following equation:

number

[0128] Substituting equation (19) into equation (18), we obtain the following equation.

number

[0129] I X =V X / Z X and Z X =1 / (2πωC X ) Substituting and simplifying the result, we get insulated wire 2 AC voltage within 106 (V AC ) can be expressed by the following formula:

number

[0130] The determined AC voltage of the insulated wire 2106 can then be displayed to an operator or communicated to an external device via a suitable communication interface.

[0131] 22 is a flow diagram of a method 2700 of operating a non-contact voltage measurement system to measure AC voltage in an insulated wire without galvanic contact. The non-contact voltage measurement system can be similar to or identical to any of the implementations of the non-contact voltage measurement systems discussed above and / or can include various combinations of such non-contact voltage measurement systems.

[0132] Method 2700 can begin at 2702, where an operator positions a conductive sensor of a non-contact voltage measurement system adjacent to an insulated wire to be measured. As discussed above, when the conductive sensor is positioned adjacent to the insulated wire, the sensor and conductors within the insulated wire generate a sensor capacitor C S are capacitively coupled together to form

[0133] At 2704, at least one processor (controller) of the non-contact voltage measurement system can cause a variable capacitance subsystem electrically coupled to the sensor to have a first capacitance value. In at least some implementations, the variable capacitance subsystem can include, for example, at least a first capacitor, a second capacitor, and a switch controlled by the processor.

[0134] At 2706, the at least one processor may detect or measure a first voltage across the variable capacitance subsystem and store the first measured voltage in a non-transitory process-readable storage medium. As discussed above, in at least some implementations, the at least one processor may detect or measure the voltage across the variable capacitance subsystem via an ADC having a relatively high (e.g., 20-bit, 22-bit) effective resolution.

[0135] At 2708, the at least one processor of the non-contact voltage measurement system can cause the variable capacitance subsystem to have a second capacitance value different from the first capacitance value. In at least some implementations, one of the first capacitance value and the second capacitance value can be at least twice the other of the first capacitance value and the second capacitance value. As a non-limiting example, each of the first and second capacitance values ​​can be between 1000 pF and 5000 pF.

[0136] At 2710, the at least one processor may detect or measure a second voltage across the variable capacitance subsystem and store the second measured voltage in a non-transitory process readable storage medium.

[0137] At 2712, the at least one processor may determine an AC voltage in the insulated conductor based at least in part on the first and second measured voltages and the first and second capacitance values. For example, as discussed above, the at least one processor may determine an AC voltage in the insulated conductor (V AC ) can be determined according to the formula: V AC =V M1 ×[(C1 / C2)-1] / [(C1V M1 / C2V M2 )-1] (22) where C1 and C2 are first and second capacitance values, respectively, and V M1 and V M2 are the first and second measured voltages across the variable capacitance subsystem.

[0138] After determining the AC voltage in the insulated conductor, the at least one processor can present the results to an operator via a user interface communicatively coupled to the at least one processor. The user interface can include a visual component (e.g., a display, a light (e.g., LED), multiple lights (e.g., LEDs)) and / or an audio component (e.g., speaker, buzzer). Additionally or alternatively, the at least one processor can communicate the results to an external device via a suitable wired and / or wireless communication interface.

[0139] In at least some implementations, after obtaining the second measured voltage, the at least one processor can cause the variable capacitance subsystem to have a third capacitance value, and in such instances, the at least one processor can then sense or measure the third measurement voltage across the variable capacitance subsystem.

[0140] The at least one processor then measures the AC voltage in the insulated conductor (V AC ) to the first measured voltage (V M1 ), the second measured voltage (V M2 ), the third measured voltage (V M3 ), a first capacitance value (C1), a second capacitance value (C2) and a third capacitance value (C3) at least partially For example, the at least one processor may determine the AC voltage (V AC ) can be determined according to the formula: V AC =C3V M3 ×[(V M2 -V M1 ) / (C1V M1 -C2V M2 )]+V M3 (twenty three)

[0141] Then, the determined AC voltage (V AC) may be presented to an operator via a suitable interface and / or communicated to an external device via a wired and / or wireless communication interface.

[0142] Multi-capacitor type non-contact voltage measurement system The subject matter discussed below is directed to systems and methods that use a multi-capacitor voltage measurement sensor or system to measure the AC voltage of an insulated or blank non-insulated conductor (e.g., an insulated wire) without requiring a galvanic connection between the conductor and a test electrode or probe. Implementations disclosed in this section may be referred to herein as "multi-capacitor voltage sensors" or systems. Generally, a non-galvanic contact (or "non-contact") voltage measurement system is presented that uses a capacitive sensor to measure the AC voltage signal in an insulated conductor relative to ground.

[0143] FIG. 23A is a pictorial diagram of an environment 3100 in which a non-contact voltage measurement system 3102, including a multi-capacitor voltage sensor or system, can be used by an operator 3104 to measure AC voltage present in an insulated conductor 3106 without requiring galvanic contact between the non-contact voltage measurement system and the wire 3106. FIG. 23B is a top view of the non-contact voltage measurement system 3102 of FIG. 23A illustrating various electrical characteristics of the non-contact voltage measurement system during operation. The non-contact voltage measurement system 3102 includes a housing or body 3108 that includes a gripping portion or end 3110 and a probe portion or end 3112, also referred to herein as the front end, opposite the gripping portion. The housing 3108 can also include a user interface 3114 to facilitate user interaction with the non-contact voltage measurement system 3102. The user interface 3114 can include any number of inputs (e.g., buttons, dials, switches, touch sensors) and any number of outputs (e.g., displays, LEDs, speakers, buzzers). The non-contact voltage measurement system 3102 may also include one or more wired and / or wireless communication interfaces (e.g., USB, Wi-Fi®, Bluetooth®) to facilitate communication with locally or remotely located devices.

[0144] In at least some implementations, as best shown in FIG. 23B, the probe portion 3112 can include a recessed portion 3116 defined by first and second extension portions 3118 and 3120. The recessed portion 3116 receives the insulated wire 3106 (see FIG. 23A) when a measurement is to be taken. The insulated wire 3106 includes a conductor 3122 and an insulator 3124 that surrounds the conductor 3122. The recessed portion 3116 accommodates the sensors or electrodes S1, S2, and S3. The sensors or electrodes S1, S2 and S3 may include insulated wires for non-contact voltage measurement. When positioned within the recessed portion 3116 of the stem 3102, the sensors S1 and S2 are positioned adjacent to the insulator 3124 of the insulated wire 3106. In the illustrated embodiment, the sensors S1 and S2 are disposed inside the extension portion 3118 of the housing 3108, and the sensor S3 is disposed adjacent the extension portion 3118 of the housing 3108. 3120. A surface 3119 of extension portion 3119 may be provided to separate sensors S1 and S2 from recessed portion 3116 to prevent physical and electrical contact between the sensors and other objects (e.g., insulated wire 3106, metal objects). Similarly, a surface 3121 of extension portion 3120 may separate sensor S3 from recessed portion 3116. As discussed below with reference to FIG. 27, in at least some implementations, surface 3119 may be spaced apart from the surface 3121 by a distance that separates sensor S3 from the recessed portion (e.g., 100 mm from the recessed portion of FIG. 27). The sensors S1 and S2 can be separated from the recessed portion 3116 by a distance (eg, thickness T1 in FIG. 27) different from the thickness T2.

[0145] As shown in FIG. 23A, in use, an operator 3104 can grasp the gripping portion 3110 of the housing 3108 to position the probe portion 3112 adjacent to an insulated electrical wire 3106 such that the non-contact voltage measurement system 3102 can accurately measure the AC voltage present in the wire relative to ground (or another reference node). Although the probe end 3112 is shown as having a recessed portion 3116, in other implementations the probe portion 3112 can be configured differently. For example, in at least some implementations the probe portion 3112 can include a selectively movable clamp, hook, sensor, etc. The interface may include a flat or arcuate surface, or other type of interface that allows a sensor of the non-contact voltage measurement system 3102 to be positioned in close proximity to the insulated wire 3106.

[0146] When the probe portion 3112 is positioned proximate to the insulated wire 3106, the sensors S1, S2, and S3 each capacitively couple to the wire's conductor 3122 generating capacitances C1, C2, and C3, respectively. As discussed further below, each of the sensors S1, S2, and S3 This is the AC voltage (V O ) to accurately determine the sensors S1 and S2 and S3 differ from each other with respect to at least one characteristic that affects capacitive coupling with the insulated wire 3106 so that different voltages V1, V2 and V3 at S3 can be detected and used.

[0147] In at least some implementations, the output voltages V1, V2, and V3 and various ratios are The insulated conductor 3106 is used to determine a characteristic of the conductor 3106. The determined characteristic can be used to determine the AC voltage in the insulated conductor 3106 via a calibrated lookup table and / or one or more determined equations.

[0148] The particular system and method used by the non-contact voltage measurement system 3102 to measure AC voltage is discussed below with reference to FIGS.

[0149] 24 shows a schematic diagram of various internal components of the non-contact voltage measurement system 3102 also shown in FIG. 23A and FIG. 23B. In this embodiment, the conductive sensors S1, S2, and S3 of the non-contact voltage measurement system 3102 are positioned in close proximity to the insulated wire 3106 under test. Each of the sensors S1, S2, and S3 is connected to the insulated wire 3106. Sensor coupling capacitors C1, C2, and C3 (FIG. 23B) are capacitively coupled to conductor 3122. The AC voltage signal (V O ) generate sensor voltage signals V1, V2 and V3 at the sensors S1, S2 and S3, respectively, which are The capacitances C1, C2 and C3 of the sensors S1, S2 and S3 respectively.

[0150] The AC voltage (V O ) is connected to an external ground 3128 (e.g., neutral) The non-contact voltage measurement system 3102 itself also has a capacitance to ground 3128, which is primarily the human body capacitance (C B Each of the capacitances C1, C2, and C3 is a conductive loop. B The voltage inside the loop is generated via the respective signal The current signals (I1, I2, and I3) are generated by the A in the conductor 3122 of the insulated wire 3106, which are capacitively coupled to the conductive sensors S1, S2, and S3, respectively. C Voltage signal (V O ) and the housing 3 of the non-contact voltage measurement system 3102 108 and the human body capacitor (C B ) back to external ground 3128 The current signals (I1, I2, and I3) are a function of the distance between the conductive sensors S1, S2, and S3, respectively, and the insulated wire 3106 under test, the particular shape and size of the conductive sensors S1, S2, and S3. , and the size and voltage level (V O ) and the relative position The voltages V1, V2 and V3 are proportional to the current signals I1, I2 and I3, respectively. If there is a connection from the internal ground guard 3154 (see Figures 25, 26A, 26B and 27) to a measured reference potential, such as a test lead, then the ground (body capacitance C B ) for Other reference potentials may also be used. This connection, if used, reduces the low body capacitance C when connected to earth / ground. B It is also possible to nullify the effect of This would be a phase-to-phase measurement in a multi-phase environment where the internal ground guard 3154 is connected to one phase and the non-contact sensor 3112 is used on another phase.

[0151] To reduce or avoid stray currents, at least a portion of the non-contact voltage measurement system 3102 (e.g., sensors S1, S2, and S3) may be connected to a conductive internal ground guard or screen 313. 2A-B (also shown in FIGS. 26A-B), causing most of the current to pass through the conductive sensors S1, S2, and S3, which are coupled to the conductor 3122 of the insulated wire 3106 and the coupling capacitors C1, C2, and C3. The internal ground guards 3132A-B may be formed from any suitable conductive material (e.g., copper) and may be solid (e.g., foil) or may have one or more openings (e.g., mesh). Guards 3132A-B around S1, S2 and S3 may also reduce the effects of stray adjacent wires close to the sensors. Guards 3132A-B, also referenced by reference numeral 3154 in Figures 25, 26A, 26B and 27, provide an internal ground connection for the non-contact voltage measurement system 3102.

[0152] As shown in FIG. 24, the non-contact voltage measurement system 3102 can include a voltage measurement subsystem 3136 that includes voltage measurement components 3136A, 3136B, and 3136C that measure voltage signals V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13, V14, V15, V16, V17, V18, V19, V20, V21, V22, V23, V24, V25, V26, V27, V28, V29, V30, V31, V32, V33, V34, V35, V36, V37, V38, V39, V40, V41, V42, V43, V44, V45, V46, V47, V48, V49, V50, V5 V2 and V3, and / or respective current signals I1, I2 and I3 which are proportional to the voltage signals As a non-limiting example, each of the voltage measurement components 3136 may be an analog-to-digital converter (ADC) that detects the voltage signals V1, V2, and V3. ) and associated circuitry. As another non-limiting example, each of the voltage measurement components 3136A, 3136B, and 3136C can include an input amplifier and feedback circuit that operates as an inverting current-to-voltage converter to convert input currents I1, I2, and I3, which are proportional to the voltage signals V1, V2, and V3, into voltage levels.

[0153] The voltage signals V1, V2 and V3 (or representative signals thereof) are fed to a signal processing module 3140. , and a signal processing module 3140 processes the voltage signals V1, V2, and V3 to produce an AC voltage (V O ). The signal processing module 3140 may include any combination of digital and / or analog circuitry.

[0154] The non-contact voltage measurement system 3102 also measures the determined AC voltage (V O ) or , may also include a user interface 3142 (eg, a display) communicatively coupled to the signal processing module 3140 for communicating to an operator 3104 of the non-contact voltage measurement system via the interface.

[0155] FIG. 25 illustrates conductive sensors S1, S2, and S3 of a non-contact voltage measurement system 3102 positioned proximate to an insulated conductor 3106 during a measurement of an insulated wire, according to one illustrated implementation. 3 is a schematic diagram illustrating an embodiment of a conductive sensor 3106 having an insulated conductor 3106. In this embodiment, the conductive sensor S1 is separated from the insulated conductor 3106 by a first distance D1, the conductive sensor S2 is separated from the insulated conductor 3106 by a second distance D2, and the conductive sensor S3 is separated from the insulated conductor 3106 by a third distance D3. In at least some implementations, at least one of the distances D1, D2, and D3 is At least one of the distances D1, D2, and D3 may be different from the other distances. In at least some implementations, the distances D1 and D2 may be equal to each other, and the distance D3 may be 27, the distances D1, D2, and D3 may be different from each other. The thickness of the insulating layer may be controlled, at least in part, by the physical properties (eg, thickness) of one or more insulating layers.

[0156] As also shown in FIG. 25, the conductive sensors S1, S2 and S3 have different physical dimensions. (e.g., height, width, shape, area). In the illustrated embodiment, conductive sensor S1 has a width (W1) that is less than the width (W2) of conductive sensor S2, and conductive sensor S2 has a width (W2) that is less than the width (W3) of conductive sensor S3. Such differences in sensors S1, S2, and S3 allow for the use of voltages V1, V2, and V3 to uniquely determine the AC voltage in the insulated wire. Allows measurement of V3.

[0157] 26A is a plan view of first and second conductive sensors S1 and S2 at least partially surrounded by an internal ground guard 3132A. In this embodiment, sensor S1 Sensor S1 has a planar right triangle defining a first edge 3150A and a second edge 3150B forming a right angle at corner 3151 and a hypotenuse edge 3150C opposite the right angle. Similarly, sensor S2 has a first edge 3152A and a second edge 3153B forming a right angle at corner 3153. 2B and a right angled opposing hypotenuse edge 3152C. In this embodiment, the sensors S1 and S2 are inverted with respect to one another such that the hypotenuse edges 3150C and 3152C of the first and second conductive sensors S1 and S2, respectively, are positioned beside (e.g., substantially adjacent) one another with a small gap therebetween.

[0158] FIG. 26B is a top view of the third conductive sensor S3 at least partially surrounded by an internal ground guard 3132B. In this embodiment, the third conductive sensor S3 is rectangular in shape. In at least some implementations, the area of ​​the third sensor S3 is The combined area of ​​the third sensor S3 is the same (or substantially the same) as the combined area of ​​the first and second conductive sensors S1 and S2, although such a feature is not a requirement. In instances where the third sensor S3 is the same as the combined area of ​​the first and second conductive sensors S1 and S2, and the sensors S1 and S2 are spaced apart from the insulated wire by a distance different than the distance that the sensor S3 is spaced apart from the insulated wire, the combined sensors S1 and S2 can be considered as a single capacitance (C1+C2) that can be compared to capacitance C3 to account for the difference in distance using a capacitor of similar shape. .

[0159] The particular shapes, sizes, relative positions and orientations of sensors S1, S2 and S3 are exemplary; It should be appreciated that this is not limiting. In fact, any one of sensors S1, S2 and S3 may be used. Their shapes, sizes, relative positions and orientations can be varied in numerous combinations.

[0160] FIG. 27 illustrates a front end 3102 of a non-contact voltage measurement system 3102 including sensors S1, S2, and S3. 112. Sensors S1 and S2 may be supported by a circuit board 3156A, which is at least partially surrounded by an internal ground guard 3132A. Similarly, sensor S3 may be supported by a circuit board 3156B. , the circuit board 3156B is at least partially surrounded by an internal ground guard 3132B.

[0161] A first insulating layer 3158A separates sensors S1 and S2 from the recessed portion 3118 of the front end 3112. A second insulating layer 3158B separates sensor S3 from the recessed portion 3118 of the front end. The first and second insulating layers 3158A and 3158B can have flat surfaces 3119 and 3121, respectively, disposed at an acute angle (α) relative to one another to define a “V” shaped recess 3116 that receives the insulated conductor therein. As a non-limiting example, the angle (α) can be between 20° and 50° (e.g., 39°, 42°) in at least some implementations. Exemplary insulated conductors 3162, 3164, and 3166 are shown disposed within the recess 3116 near the flat surfaces 3119 and 3121. Insulated conductor 3162 includes a wire 3162B surrounded by insulation 3162A, insulated conductor 3164 includes a wire 3164B surrounded by insulation 3164A, and insulated conductor 3166 includes a wire 3166B surrounded by insulation 3166A.

[0162] In the embodiment shown in FIG. 27, the front or probe end 3112 may be made of various insulated wires, such as a relatively large diameter insulated wire 3162 or a relatively small diameter insulated wire 3166. The insulated wires 3162, 3164, and 3166 can also have conductors 3162A, 3164A, and 3166A, respectively, having different diameters and / or respective insulation layers 3162B, 3164B, and 3166B having different thicknesses.

[0163] The first insulating layer 3158A can have a first thickness T1, and the second insulating layer 315 8B can have a second thickness T2. In at least some implementations, the first The thickness T1 may be different from the second thickness T2. For example, in at least some implementations, the first thickness may be approximately 0.5 millimeters (mm) and the second thickness T2 may be approximately 0.5 mm. , may be approximately 2.5 mm.

[0164] By installing three sensors S1, S2 and S3 that differ from each other with respect to at least one characteristic that affects the capacitive coupling with the insulated wire under test (e.g., size, shape, distance from the insulated conductor 3106), the non-contact voltage measurement system 3102 can measure the capacitance between the sensors and the insulated conductor 3106. This allows compensation for different variables that affect the capacitive coupling between the insulated conductor 3106 and the insulated conductor 3106, such as the diameter of the insulated conductor 3106, the thickness of the insulation of the insulated conductor 3106, the position of the insulated conductor 3106 within the recessed portion 3116 of the front end 3112, etc.

[0165] Advantageously, voltage measurements of voltages V1, V2 and V3 are taken from sensors S1, S2 and By acquiring the voltage at least one processor of the non-contact voltage measurement system 3102 at S3, The processor can accurately determine the AC voltage on the insulated conductor 3106. To make such a determination, the non-contact voltage measurement system 3102 can be calibrated (e.g., during manufacture or design) using a known insulated conductor 3106 having a known AC voltage. Additionally or alternatively, at least one processor of the non-contact voltage measurement system 3102 can utilize one or more determined equations, along with voltages V1, V2, and V3 as inputs. In operation, at least one processor in the non-contact voltage measurement system 3102 receives the voltages V1, V2, and V3 and supplies as an output the AC voltage of the insulated conductor 3106. The AC voltage in the insulated wire can then be determined using a lookup table or one or more equations that take the voltage as an input and output the AC voltage in the insulated wire.

[0166] 26A, 26B, and 27, various relationships between the voltages V1, V2, and V3 measured by sensors S1, S2, and S3, respectively, can be used to determine the AC voltage of the insulated conductor under test. In at least some implementations, the non-contact voltage measurement system 3102 can utilize one or more of the following relationships:

number

[0167] Using the above relations (24) to (27), the AC voltage in insulated conductors of various sizes can be measured independently of the distance between the insulated conductors and the sensors S1, S2, and S3. The function given above can be provided for an unknown AC voltage in an insulated conductor (e.g., insulated conductor 3106).

[0168] For sensors S1 and S2 the following equations can be used: V O =k×(V1+V2) (28) In the formula, V O is the AC voltage in the insulated conductor, and k is a function of the above relation (24). (i.e., k=f(V1 / V2)).

[0169] The measured voltages V1, V2 and V3 depend on the capacitances C1, C2 and C3 between the sensors S1, S2 and S3 and the insulated conductor, respectively. - Capacitance between wires (e.g., insulated conductors) parallel to each of S1, S2, and S3 The capacitances C1, C2 and C3 can be calculated according to known formulas for the sensor. The equation for each of these capacitances C is as follows:

number

[0170] As discussed above, current is directed through each of the sensors S1, S2 and S3. Voltages V1, V2, and V3 can be measured with suitable voltage measurement components 3136A, 3136B, and 3136C, respectively, such as one or more ADCs or one or more inverting operational amplifiers that convert the voltages V1, V2, and V3 into a single voltage.

[0171] The above relations (24), (25) and (26) are expressed as follows: Identify the three equations that provide for given measurements, and for given measurements of voltages V1, V2, and V3, The diameter of the conductor under test and the insulation thickness of the conductor can then be identified and used to calculate the capacitances C1, C2, and C3 using equation (29) above. The pressure can be calculated according to the following formula:

number

[0172] The three output voltages V1, V2 and V3 of the three sensors S1, S2 and S3 allow the characterization of the insulated wire under test by the conductor diameter and insulation thickness. The relationship (24) above primarily defines the outside diameter of the insulated wire, and the relationship (27) primarily defines the conductor diameter of the insulated wire. As discussed above, the voltages V1, V2 and V3 are derived from look-up tables. The calibration coefficients may be used as inputs to obtain calibration coefficients from a calibration log or to calculate calibration coefficients using one or more equations.

[0173] As an example, for given measurements of voltages V1, V2 and V3, using equation (29) above: Relation (24) then specifies the possible combinations of wire diameter and insulation thickness for the insulated wire under test. Similarly, relationship (25) limits the possible combinations of wire diameter and insulation thickness for the insulated wire under test. Thus, using relationships (24) and (25), a hypothetical wire having a specified wire diameter and a specified insulation thickness can be determined. The physical properties of the determined hypothetical wire can be used to identify a factor "k" that depends on both relationships (24) and (25) above. The determined hypothetical wire and the measured voltages V1 and V2 can be calculated by the following equation: Using V2, the position is determined by a calibration table generated by different positions of the insulated wire under test. This gives a final voltage result that is independent of the measurement location.

[0174] Using only voltages V1 and V2 may result in inaccurate values. Therefore, using voltage V3 from sensor S3 as well as the voltages discussed above may provide a better position definition. In particular, relationship (27) utilizes the sum of voltages V1 and V2. Note that the geometry of sensors S1 and S2 when coupled together is similar to the geometry of sensor S3. From this, the relationship (27) gives the ratio of similar capacitors (i.e., C1+C2 and C3) at two different distances (i.e., T1 and T2).

[0175] The actual size and shape of the sensors S1, S2 and S3 can be selected so that a reasonable capacitance (e.g., a few picofarads) is achieved between the sensors and the insulated wire under test, and is well below the human body capacitance (CB) (e.g., 30 to 200 picofarads), and the human body capacitance (CB ) can be used as a possible reference for grounding in handheld applications.

[0176] Non-contact AC Electrical Parameter Measurement System The following discussion presents various example implementations of a non-contact measurement system that can include some or all of the functionality discussed herein.

[0177] 28 is a schematic block diagram of a non-contact measurement system or instrument 3700 that provides non-contact voltage measurement functionality and non-contact current measurement functionality. The measurement system 3700 can also determine one or more AC electrical parameters (e.g., power, energy, frequency, harmonics) derived from the voltage and / or current measurements. The measurement system 3700 includes a voltage sensor 3702 and a current sensor 3704 that are each communicatively coupled to a processor 3706.

[0178] The voltage sensor 3702 and / or the processor 3706 may be similar or identical to any of the non-contact detectors discussed herein. The processor 3706 may include one or more logic circuit processing devices, such as one or more central processing units (CPUs), microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), and the like. The measurement system 3700 may also include a memory 3708 communicatively coupled to the processor 3706 for storing at least one of instructions or data. The memory 3708 may include, for example, one or more solid state memories flash memories or solid state drives (SSDs), where the one or more solid state memories provide non-volatile storage of computer readable instructions, data structures, program modules, and other data for the measurement system 3700. Although not shown, the measurement system 3700 may employ other non-transitory computer readable or processor readable media, such as a hard disk drive, an optical disk drive, or a memory card media drive.

[0179] The measurement system 3700 can include a user interface 3710, which can include any number of inputs (e.g., buttons, dials, switches, touch screen) and any number of outputs (e.g., displays, LEDs, speakers, buzzers). The measurement system 3700 can also include one or more displays 3712 that show readouts 3714 and / or waveforms 3716. can.

[0180] In operation, the processor 3706 receives signals from the voltage sensor 3702 and the current sensor 3704 to obtain voltage and current measurements, respectively. The processor 3706 can use such voltage and current measurements to derive additional AC electrical parameters based on a combination of the measurements. Such parameters can include, for example, power (true power, apparent power, etc.), phase (e.g., three-phase), frequency, harmonics, energy, etc.

[0181] The voltage sensor signal and the current sensor signal may be acquired by the respective voltage sensor 3702 and current sensor 3704 during a common measurement time interval, which may be relatively short in duration (e.g., 10 milliseconds (ms), 100 ms, 1 second, 10 seconds). For example, the voltage sensor 3702 and the current sensor 3704 may acquire measurements at least partially in parallel with one another. As another example, one of the voltage sensor 3702 and the current sensor 3704 may acquire a measurement substantially immediately after the other of the voltage sensor and the current sensor acquires a measurement, such that the measurements are acquired approximately simultaneously. In some implementations, the voltage sensor 3702 and the current sensor 3704 may be operated to acquire measurements simultaneously or sequentially repeatedly at specified intervals (e.g., every 10 ms, every 100 ms, every second, every 10 seconds). Generally, both the voltage sensor 3702 and the current sensor 3704 take their respective measurements within a measurement time interval that is short enough so that pairs of voltage and current measurements correspond to each other, thereby enabling accurate derivation or determination of one or more AC electrical parameters (e.g., power, phase) using the taken current and voltage measurements.

[0182] The processor 3706 may provide a readout 3714 of one or more of the measured or derived parameters and may provide a graphical representation of one or more characteristics. Such graphical representations may include waveforms, harmonic bar graphs, etc. Exemplary signal characteristics that may be shown via the display 3712 include voltage, current, frequency, power parameters (e.g., watts, kVA), phase, energy, harmonics, phase sequence detection, etc.

[0183] Figure 29 is a schematic block diagram of a non-contact measurement system or instrument 3800 that provides non-contact voltage measurement functionality and / or non-contact current measurement functionality. Measurement system 3800 is in many respects similar or identical to measurement system 3700 of Figure 28, so only the relevant differences will be discussed herein for the sake of brevity.

[0184] In this implementation, the measurement system 3800 may not include a display, but instead may be used as a "leave-behind" sensor that remotely monitors the electrical device via an external processor-based device 3806. Such a processor-based device 3806 may include various types of devices, such as smartphones, tablet computers, laptop computers, wearable computers, servers, cloud computers, etc. The external processor-based device 3806 may include a display that shows data collected by the measurement 3800 over a period of time (e.g., minutes, hours, days, weeks, years).

[0185] To communicate with one or more external processor-based devices, the measurement system may include one or more wired communication interfaces 3802 and / or one or more wireless communication interfaces 3804.

[0186] Non-limiting examples of wireless communication interface 3804 include Wi-Fi, Bluetooth, Bluetooth Low Energy, Zigbee, 6LoWPAN, Optical IR, Wireless HART, etc. Non-limiting examples of wired communication interface 3802 include USB, Ethernet, PLC, HART, MODBUS, FireWire, Thunderbolt, etc.

[0187] In addition to sending data to the external device 3806, in at least some implementations, the measurement system 3800 can receive at least one of data or instructions (e.g., control instructions) from the external device 3806 via the wired communication interface 3802 and / or the wireless communication interface 3802.

[0188] 30 illustrates a portion of a front or probe end 3900 of a measurement system, such as measurement system 3800. The measurement system may be similar or identical to one or more of the measurement systems discussed herein. In this implementation, the front end 3900 of the measurement system includes a fixed jaw 3902 having first and second spaced apart projections 3902a and 3902b that define a recessed portion 3904 that receives an insulated conductor under test (not shown for clarity). Proximate an innermost portion 3906 of the recess 3904 is a sensor 3908 that is operative to measure at least one of a voltage and a current in the insulated conductor under test.

[0189] The front end 3900 of the measurement system also includes one or more alignment feedback sensors 3910 disposed about the prongs 3902a and 3902b that can be used to provide various information to a user during a measurement operation. For example, in at least some implementations, the one or more alignment feedback sensors 3910 can be used to provide feedback to a user regarding the alignment of the insulated conductors relative to the front end 3900. Such can be accomplished by utilizing the one or more alignment feedback sensors 3910 to determine the location of the insulated conductors and provide an indication of such location to the user.

[0190] For example, the display 3912 of the measurement system can provide alignment feedback information to the user. As another example, colored lights (e.g., LEDs) can be used to provide alignment feedback to the user. As an example, a red light can be illuminated to indicate that the insulated conductors are not aligned, a yellow light can be illuminated to indicate that the insulated conductors are nearly aligned, and a green light can be illuminated to indicate that the insulated conductors are properly aligned. As another example, a graphical representation of the position of the insulated conductors relative to the front end 3900 can be displayed on the display. As another example, sound can be used to provide alignment feedback. For example, the measurement system can generate a "beep" or other sound at a varying interval, intensity (volume) or frequency based on whether the insulated conductors are aligned (e.g., a slow beep for no alignment, a faster beep for nearly aligned, and a fastest or steady beep for aligned).

[0191] In at least some implementations, one or more alignment feedback sensors 3910 may alternatively or additionally be used to detect an actual voltage (e.g., an energized circuit near the conductor under test) in the vicinity. If such an actual voltage is detected, an indication (e.g., sound, light, warning message) may be provided to notify a user that an actual voltage is nearby.

[0192] In at least some implementations, one or more alignment feedback sensors 3910 may be used to provide an indication of the accuracy of measurements taken by a user. For example, when a user takes a measurement, a color-coded signal (e.g., red, yellow, green) may be provided to inform the user that the measurement accuracy is good (green), marginal (yellow), or poor (red) based on the alignment determination. In addition to color or graphic alignment feedback, other forms of feedback may be provided. For example, the determined alignment information may be shown as a numerical value, as a bar graph, as a "hot / cold" indicator, or as any other suitable indicator.

[0193] 31-41B each show various embodiments of a measurement tool that can incorporate at least a portion of the functionality discussed herein. FIG. 31 shows a measurement tool 4000 that includes a housing 4002, a readout display 4004, a front end 4006 that includes a sensor, and a retractable clamp or jaw 4008 that grips an insulated electrical wire. The clamp or jaw 4008, as well as other clamps or jaws of the present disclosure, may be permanently attached to the housing 4002 or may be selectively detachable. FIG. 32 shows a measurement tool 4100 that includes a housing 4102, a readout display 4104, a front end 4106 that includes a sensor, and a fixed jaw 4108 that receives an insulated conductor therein. Figure 33 shows a measurement tool 4200 including a housing 4202, a readout display 4204, a front end 4206 with a sensor, and a retractable hook 4208 for gripping the insulated conductor under test. Figure 34 shows a measurement tool 4300 including a housing 4302, a display 4304 with a readout and graphical information (e.g. waveform, harmonics graph), a front end 4306 with a sensor, and a retractable hook 4308 for gripping the insulated conductor under test. Figure 35 shows a measurement tool 4400 including a housing 4402, a display 4404, and an arcuate shaped front end 4406 with a sensor therein.

[0194] 36 shows a measurement tool 4500 including a housing 4502, a readout display 4504, a front end 4506 with a sensor, a retractable hook 4508, and an optional reference lead 4510. The measurement tool 4500 can be used to measure and / or derive a variety of electrical properties including, but not limited to, non-contact AC voltage, AC current, DC voltage, resistance, frequency, phase, kWh, KW, VA, var, PF, THD, inrush current, phase sequence, and voltage drop testing.

[0195] An exemplary form factor of the measurement system 3800 is shown in FIG. 37, which illustrates a measurement tool 4600 including a clamp 4602 extending from a housing portion 4604 that grips the insulated conductor to be measured and an optional clip 4606 that can be coupled to a reference node. In operation, a user can place the clamp 4604 onto the insulated conductor to be measured, and the measurement tool 4600 can take current measurements and / or current measurements over a period of time (e.g., seconds, minutes, hours, days, weeks, years) and derive one or more additional AC electrical parameters from the measurements. The measurement data and / or derived parameters can be sent in real time or at determined intervals to one or more external processor-based devices, which can process such data and / or present it to a user via a suitable user interface (e.g., a display). As discussed above, the measurement tool 4600 can also receive instructions or data from one or more external devices via wired and / or wireless communication.

[0196] 38 illustrates a measurement device 4700 that includes a first housing 4702 electrically coupled to a second housing 4704 by a cable 4706. The housing 4702 can include a display 4708 thereon that shows measurement information to a user. The first housing 4702 can include a front end 4710 having a sensor therein for obtaining non-contact voltage measurements. Similarly, the second housing 4704 can include a front end 4712 having a sensor therein for obtaining non-contact voltage measurements. In operation, one or both of the first and second housings 4702 and 4704 can be used to obtain individual non-contact AC voltage measurements and / or individual AC voltage current measurements. Additionally, when the front end 4710 of the first housing 4702 is positioned proximate to a first insulated conductor and the front end 4712 of the second housing 4704 is positioned proximate to a second insulated conductor, the measurement system 4700 can obtain a combined non-contact phase-to-phase AC voltage measurement between the two insulated conductors.

[0197] FIG. 39 illustrates a measurement instrument 4800 that includes a housing 4804 having multiple test leads 4802 coupled thereto. The measurement instrument 4800 can wirelessly communicate with an external processor-based device 4806 (e.g., smartphone, tablet) that can serve as a user interface to control the measurement instrument and present measurements obtained by the measurement instrument on a display 4808. In at least some implementations, the measurement instrument 4800 can measure and present (e.g., via the external processor-based device 4806) operational cycles of fans, compressors, pumps, etc., and / or operating characteristics of heating, cooling, and / or lighting systems. The measurement instrument 4800 can also measure and / or derive, for example, non-contact AC voltage, AC voltage, AC current, DC voltage, resistance, frequency, phase, kWh, KW, VA, var, PF, and THD.

[0198] 40 shows a measurement tool 4900 including a housing 4902, a display 4904, and a front end 4906 with a sensor therein for measuring non-contact AC voltage. Measurement tool 4900 can be used to measure or detect high voltages (e.g., greater than 1 kV). A hot stick (e.g., a telescopic hot stick) can be optionally coupled to measurement tool 4900 to test high AC voltages without touching or disconnecting the circuit. Such can be useful, for example, in utility, industrial, and mining applications when working with high voltage equipment such as transmission lines, fallen power lines, fuses, and load break connectors.

[0199] 41 illustrates a measurement instrument 5000 that includes a housing 5002, a display panel 5004 (e.g., a touch screen), three signal input leads 5006, and a reference input lead 5008. Measurement instrument 5000 is operable to measure, for example, non-contact AC voltage, AC current, DC voltage, resistance, continuity, frequency, phase, kWh, KW, VA, var, PF, THD, inrush current, phase sequence, and voltage drop tests.

[0200] 42A and 42B show an infrared camera 5100, which includes a housing 5102 and a display 5104. The infrared camera 5100 includes a front end portion 5106 that includes a sensor that can be used to alternately or simultaneously measure non-contact AC voltage and AC current. The infrared camera 5100 can provide a visual image on the display 5104 and can optionally be laser guided. In at least some implementations, the infrared camera 5100 can be communicatively coupled to an external processor-based device (e.g., a smartphone, a tablet computer, another measurement instrument) via a wired and / or wireless communication interface (e.g., spiral cable, Bluetooth® Low Energy).

[0201] One or more of the measurement systems or instruments of the present disclosure may be configured to provide the following features: The test features may include one or more of: smaller jaw width for better access to wires without contact, wider jaw opening for larger conductors, flashlight, non-contact AC voltage to ground measurement, non-contact AC voltage phase to phase measurement, non-contact AC voltage indicator, backlit display, ghost voltage detection (low Z), impedance, sound, replaceable test leads, optional flex clamps, capacitance measurement, auto hold, temperature measurement, true RMS, current (e.g., mA), DC, power, etc.

[0202] Non-contact current measurement system The systems and methods disclosed herein provide a non-contact current measurement system that measures the current flowing through an insulated wire without requiring galvanic contact with the conductor of the insulated wire. The non-contact current measurement system discussed herein can be implemented as a stand-alone ammeter or can be combined with one or more other implementations discussed herein to provide additional functionality, such as measuring various AC electrical parameters (e.g., power, phase, frequency, harmonics, energy). In at least some implementations, the non-contact current measurement system includes a magnetic field sensor that is selectively positionable in proximity (e.g., adjacent) to the insulated wire under test. Non-limiting examples of magnetic field sensors include magnetic field sensors such as anisotropic magnetoresistance (AMR) sensors, giant magnetoresistance (GMR) sensors, fluxgate sensors, SQUID sensors, fiber optic sensors, optically excited sensors, nuclear procession sensors, search coil sensors, magnetotransistor sensors, magnetodiode sensors, optical magneto sensors, Hall effect sensors, Rogowski coils, current transformers, or other types of magnetic field sensors. Magnetic field sensors detect the magnetic field generated by a current flowing in an insulated wire. The magnitude of the magnetic field surrounding the insulated wire conductor is related to (e.g., proportional to) the magnitude of the current flowing through the insulated wire conductor.

[0203] In addition to detecting the magnetic field surrounding the conductor, at least some implementations of the present disclosure utilize an adjustable clamping assembly to control the mechanical positioning of the insulated wire relative to the magnetic field sensor. Additionally, in at least some implementations, the non-contact current measurement system determines information related to at least one physical dimension of the insulated wire under test, such as an outer diameter or gauge of the conductor inside the insulation of the insulated wire. Using the detected magnetic field, the controlled mechanical positioning, and the determined physical dimension information, the non-contact current measurement system accurately determines the magnitude of the current flowing through the conductor of the insulated wire.

[0204] Figure 43 is a pictorial representation of an environment 5200 in which a non-contact current measurement system 5202 can be used by a technician 5204 to measure AC current present in an insulated wire 5206 without requiring galvanic contact between the non-contact current measurement system and the insulated wire 5206. Figures 44A and 44B show an expanded view of the non-contact current measurement system 5202.

[0205] The non-contact current measurement system 5202 includes a housing or body 5208 that includes a gripping portion or end 5210 and a probe portion or end 5212 opposite the gripping portion. The housing 5208 can also include a user interface 5214 that facilitates user interaction with the non-contact current measurement system 5202. The user interface 5214 can include any number of inputs (e.g., buttons, dials, switches, touch sensors) and any number of outputs (e.g., displays, LEDs, speakers, buzzers). The non-contact current measurement system 5202 can also include one or more wired and / or wireless communication interfaces (e.g., USB, Wi-Fi, Bluetooth).

[0206] As shown in FIG. 44A and FIG. 44B, a magnetic field sensor 5216 (e.g., an anisotropic magnetoresistance (AMR) sensor, a giant magnetoresistance (GMR) sensor, a fluxgate sensor, or A magnetic field sensor 5216 (another magnetic field sensor) is positioned below a top surface 5218 of the front end 5212. The magnetic field sensor 5216 is used to detect a magnetic field generated by a current flowing in the insulated wire 5206, which comprises a conductor 5222 surrounded by one or more insulating layers 5224. The magnitude of the magnetic field surrounding the conductor 5222 is related (e.g., proportional) to the magnitude of the current flowing through the conductor. In general, the magnitude of the current flowing in the conductor 5222 can be accurately determined by the magnetic field sensor 5216 when two parameters are met. The first parameter is control of the mechanical positioning of the insulated wire 5206 relative to the magnetic field sensor 5216, which in at least some implementations is controlled by an adjustable clamp assembly 5226. The second parameter is physical dimensional information of the insulated wire 5206, such as the outside diameter or diameter of the conductor inside the insulation of the insulated wire (i.e., gage), which can be determined or estimated by a position feedback sensor 5228 operably coupled to the adjustable clamp assembly 5226. The adjustable clamp assembly 5226 and the position feedback sensor 5228 are discussed further below.

[0207] Further, in at least some implementations, physical dimensional information regarding the gauge of the insulated wire 5206 can additionally or alternatively be obtained utilizing one or more reference signal sensors that detect a reference signal (e.g., a reference current signal) generated between a sensor and the insulated wire 5206. Various exemplary non-contact measurement systems implementing such a "reference signal" method of detecting physical dimensional information for the insulated wire are discussed above with reference to FIGS. 1A-15. For example, in at least some implementations, an adjustable clamp assembly and position feedback sensor can be used to determine the overall diameter of the insulated wire, and a reference signal method can be used to determine the thickness of the insulation of the insulated wire. Using the determined overall diameter of the insulated wire and the determined insulation thickness, the non-contact current measurement system can automatically determine or estimate the diameter of the conductor inside the insulation of the insulated wire (e.g., the diameter of the conductor is equal to the overall diameter of the insulated wire reduced by two times the insulation thickness). The determined diameter of the conductor can then be used together with the detected magnetic field to accurately determine the magnitude of the current flowing through the insulated wire.

[0208] In the illustrated implementation, mechanical positioning of the insulated wire 5206 is provided by an adjustable clamp or "slider" clamp assembly 5226 that ensures that the insulated conductor is positioned in proper alignment (e.g., adjacent) with the magnetic field sensor 5216 during measurement. The adjustable clamp assembly 5226 includes a clamp member 5230 coupled to the housing 5208 and selectively movable toward and away from the top surface 5218 of the front end 5212. The clamp member 5230 may be referred to herein as a first clamp portion and the front end 5212 may be referred to herein as a second clamp portion. The clamp member 5230 includes a clamp surface 5232 that faces the top surface 5218 of the front end 5212 and is generally parallel to the top surface 5218. The clamping surface 5232 and the top surface 5218 together define a variable size clamping opening 5234 that is sized and dimensioned to receive a portion of the insulated wire 5206 therein. In the illustrated embodiment, the clamping member 5230 has a first position P1 in which the clamping opening 5234 is relatively large, and a second position P2 in which the clamping opening 5234 is relatively large. The opening is selectively movable between a first position P2 where the opening is relatively small and a second position P3 where the opening is relatively small.

[0209] As shown in FIG 44A, a user can position the insulated wire 5206 within the clamp opening 5234 when the clamping surface 5232 of the clamp member 5230 is spaced from the top surface 5218 of the front end 5212 an amount sufficient to allow the insulated wire 5206 to move into the clamp opening. Thereafter, as shown in FIG 44B, the user can move the clamp member 5230 downward to a third position P3 such that the top surface and the clamping surface are both spaced apart. The insulated wire 5206 is then attached to the top surface 5212 of the front end 5212 so as to contact the insulating layer of the insulated wire on both sides. 218 and clamping surface 5232. As used herein, the term "clamp" is used to refer to the insulated wire 5206 being contacted by the top surface 5218 and the clamping surface 5232 on either side of the insulated wire to maintain the position of the wire relative to the magnetic field sensor 5216. That is, the term does not necessarily indicate that the top surface 5218 or the clamping surface 5232 apply any particular amount of force to the insulated wire 5206.

[0210] The position feedback sensor 5228 is operative to sense a position (e.g., linear position) of the clamping member 5230 and generate a position feedback sensor signal (e.g., linear position feedback sensor signal) indicative of such. The position feedback signal may be, for example, a digital signal or an analog signal. When the insulated wire 5206 is clamped between the clamping surface 5232 and the top surface 5218 of the front end 5212, the sensed position of the clamping member 5230 may be used to determine or estimate a diameter or gauge of the insulated wire. For example, the position feedback sensor 5228 may provide a position feedback sensor signal that is proportional to an extension of the clamping member 5230. The position feedback sensor 5228 may be any suitable sensor operative to sense the extension of the clamping member 5230 to determine a diameter of the insulated wire 5206. For example, the position feedback sensor 5228 may include a resistive sensor, a magnetoresistive sensor, a Hall effect sensor, an optical sensor, or the like. In at least some implementations, the “reference signal” method may additionally or alternatively be used to determine the diameter or dimensions of the inner conductor of the insulated wire 5206, which may further enable the system 5202 to provide accurate current measurements.

[0211] In at least some implementations, the clamping member 5230 can be biased toward the second position P2 by a suitable biasing member 5236. For example, The second position P2 is provided by a spring coupled between the ramp member and a portion of the housing 5208. Advantageously, the biasing of the clamping members 5230 can allow the clamping assembly 5226 to better hold the insulated wire 5206 in the clamping openings 5234 while also providing a more uniform measurement of the diameter of the insulated wire 5206.

[0212] The mechanical positioning of the insulated wire 5206 relative to the magnetic field sensor 5216 can be important because of the orthogonal relationship between magnetic flux density and current flow (e.g., the "right-hand rule" of magnetic flux around a current-carrying conductor). Additionally, the physical dimensional information provided by the position feedback sensor 5228 can be important because magnetic flux density, which is tangent to the conductor's periphery and is higher in a conductor having a smaller diameter than in a conductor having a larger diameter for the same current flow. Thus, knowing at least an estimate of the diameter of the insulated wire, the non-contact current measurement system 5202 can more accurately determine the current through the insulated wire by considering the effect that the wire's diameter has on the relationship between the sensed magnetic field and the current flowing in the wire.

[0213] 48, using data from the magnetic field sensor 5216 and diameter or gauge data from the position feedback sensor 5228 and / or reference signal sensor, at least one processor of the non-contact current measurement system 5202 can accurately determine at least one characteristic (e.g., magnitude, frequency) of the current flowing through the insulated wire 5206. Such information can be presented to a user via a display of the user interface 5214, stored within a non-transitory processor-readable storage medium of the non-contact current measurement system, and / or transmitted to a separate device via a wired or wireless communication interface.

[0214] Although the illustrated non-contact current measurement system 5202 includes a magnetic field sensor 5216, other implementations may be used. In examples, it is recognized that the non-contact current measurement system can include various other types of current sensors (e.g., Hall effect sensors, Rogowski coils, current transformers, etc.) that can sense the magnetic field generated by a current without requiring galvanic contact with the wire under test.

[0215] In at least some implementations, the non-contact measurement system 5202 measures the body capacitance (C B ) may be utilized between the operator 5204 and ground 5228 during current measurements. Although the term ground is used for node 128, the node is not necessarily earth / ground but may be connected in a galvanically isolated manner to any other reference potential by capacitive coupling.

[0216] 45 illustrates a front elevational view of a non-contact current measurement system 5300, which has different form factors than the non-contact current measurement system 5202 of FIGS. 44A-B. The non-contact current measurement system 5300 may be similar or identical in many respects to the non-contact current measurement system 5202 discussed above. Thus, some or all of the content discussed above regarding the functionality of the non-contact current measurement system 5202 may also be applicable to the non-contact current measurement system 5300.

[0217] The non-contact current measurement system 5300 includes a housing 5302 having a front end 5304 and a gripping portion or end 5306 opposite the front end. The housing 5302 includes a user interface 5308 (e.g., display, buttons) positioned on a surface of the housing. The front end 5304 includes a current sensor 5312 (e.g., a magnetic field sensor), an optional reference signal sensor 5313, and a retractable jaw or clamping member 5314 that grips an insulated wire (e.g., insulated wire 5206 of FIGS. 43, 44A, and 44B). The operation of the various reference signal sensors was discussed above with reference to FIGS. 1A-15. The front end 5304 includes a front end surface 5316 adjacent the current sensor 5312, and the clamping member 5314 includes a clamping surface 5318 opposite the front end surface 5316. To further increase the accuracy of the current measurement, a second magnetic field sensor could be used within the clamping member 5314. The average signal between the current sensor 5312 and the additional sensor located within the clamping member 5314 can then be used for current calculation. Furthermore, the difference between both sensors over the boundary can be used to identify unreliable situations caused by external stray currents or improperly positioned wires clamped between the clamping members 5314 and 5316. In use, an insulated wire can be clamped between the front end face 5316 and the clamping surface 5318 to position the insulated wire adjacent the current sensor 5312. The clamping member 5314 as well as other clamping members of the present disclosure may be permanently attached to the housing 5302 or may be selectively removable from the housing. The non-contact current measurement system 5300 also includes a position feedback sensor 5320 and optionally includes a biasing member 5322 that biases the clamping member 5314 toward the housing 5302 to clamp the insulated wire between the front end face 5316 and the clamping surface 5318. Further discussion of embodiments of current sensors and position feedback sensors suitable for use in the non-contact current measurement system 5300 is presented with respect to FIG.

[0218] 46 illustrates a front elevational view of a non-contact current measurement system 5400, which has different form factors than the non-contact current measurement system 5202 of FIGS. 44A-B. The non-contact current measurement system 5400 may be similar or identical in many respects to the non-contact current measurement systems discussed above. Thus, some or all of the content discussed above regarding the functionality of the previous non-contact current measurement systems may also be applicable to the non-contact current measurement system 5400.

[0219] The non-contact current measurement system 5400 includes a front end 5404 and a gripping portion, i.e., The housing 5402 includes a housing 5402 having an end 5406. The housing 5402 includes a user interface 5408 (e.g., a display, buttons, dials) positioned on a surface of the housing. The front end 5404 includes a current sensor 5412 (e.g., a magnetic field sensor), an optional reference signal sensor 5413, and a retractable hook or clamping member 5414 for gripping an insulated wire (e.g., insulated wire 5206 of FIGS. 44, 44A, and 44B). The front end 5404 includes a front end face 5416 proximate the current sensor 5412, and the clamping member 5414 includes a clamping surface 5418 opposite the front end face 5416. In use, the insulated wire can be clamped between the front end face 5416 and the clamping surface 5418 to position the insulated wire proximate the current sensor 5412. The clamping member 5414 may be permanently attached to the housing 5402 or may be selectively removable from the housing. The non-contact current measurement system 5400 also includes a position feedback sensor 5420 and optionally includes a biasing member 5422 that biases the clamping member 5414 toward the housing 5402 to clamp the insulated wire between the front end face 5416 and the clamping surface 5418. A preferred embodiment of a current sensor and position feedback sensor that may be used in the non-contact current measurement system 5400 are presented with respect to FIG.

[0220] 47 illustrates a front elevational view of a non-contact current measurement system 5500, which has different form factors than the non-contact current measurement system 5202 of FIGS. 44A-B. The non-contact current measurement system 5500 may be similar or identical in many respects to the non-contact current measurement systems discussed above. Thus, some or all of the content discussed above regarding the functionality of the non-contact current measurement systems may also be applicable to the non-contact current measurement system 5500.

[0221] The non-contact current measurement system 5500 includes a housing 5502 having a front end 5504 and a gripping portion or end 5506 opposite the front end. The housing 5502 includes a user interface 5508 (e.g., a display, buttons, dials) positioned on a surface of the housing. The front end 5504 includes a current sensor 5512 (e.g., a magnetic field sensor), an optional reference signal sensor 5513, and a retractable hook or clamping member 5514 that grips an insulated electrical wire (e.g., insulated electrical wire 5206 of Figures 43, 44A and 44B). The front end 5504 includes a front end face 5516 proximate the current sensor 5512, and the clamping member 5514 includes a clamping surface 5518 opposite the front end face 5516. In use, the insulated electrical wire can be clamped between the front end face 5516 and the clamping surface 5518 to position the insulated electrical wire proximate the current sensor 5512. The clamping member 5514 may be permanently attached to the housing 5502 or may be selectively removable from the housing. The non-contact current measurement system 5500 also includes a position feedback sensor 5520 and optionally includes a biasing member 5522 that biases the clamping member 5514 toward the housing 5502 to clamp the insulated wire between the front end face 5516 and the clamping surface 5518. Figure 48, discussed below, provides additional illustrations of embodiments of current sensors and position feedback sensors suitable for use in the non-contact current measurement system 5500.

[0222] 48 is a schematic block diagram of a non-contact current measurement system or instrument 5600 that provides non-contact current measurement functionality. The non-contact current measurement system 5600 can be similar or identical to any of the non-contact current measurement systems discussed herein.

[0223] The non-contact current measurement system 5600 includes a current sensor 5602 (e.g., a magnetic field sensor) communicatively coupled to a processor 5604. The non-contact current measurement system 5600 also includes an adjustable clamp assembly 5606, and The adjustable clamp assembly 5606 also includes a position feedback sensor 5608 operably coupled to the adjustable clamp assembly 5606 and the processor 5604. In operation, the position feedback sensor 5608 generates a position feedback sensor signal indicative of the position of the adjustable clamp assembly 5606 and determines from the detected position the diameter of the insulated wire clamped within the adjustable clamp assembly 5606, as discussed above. The processor 5604 receives the position feedback sensor signal from the position feedback sensor 5608.

[0224] The current sensor 5602 can be any suitable non-contact current sensor, such as a magnetic field sensor, a Hall effect sensor, etc. In operation, the current sensor 5602 generates a current sensor signal indicative of at least one characteristic of the current flowing through the insulated wire clamped in the adjustable clamp assembly 5606. For example, the at least one characteristic can include a magnitude of the current or a frequency of the current. In implementations in which the current sensor 5602 is a magnetic field sensor, the current sensor can generate a magnetic field sensor signal indicative of a magnetic field generated by the current flowing through the insulated wire, which can be analyzed by the processor 5604 to determine at least one characteristic of the current flowing through the insulated wire.

[0225] The adjustable clamp assembly 5606 can be similar or identical to any of the adjustable clamp assemblies discussed herein. The position feedback sensor 5608 operates to generate a position feedback sensor signal indicative of the clamping position of the adjustable clamp assembly 5606, which in turn is indicative of the diameter of the insulated wire clamped by the adjustable clamp assembly. The position feedback sensor 5608 can be any suitable position sensor, including, but not limited to, a resistive sensor, a magnetoresistive sensor, a Hall effect sensor, an optical sensor, or the like.

[0226] The processor 5604 may include one or more logic circuit processing devices, such as one or more central processing units (CPUs), microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), microcontrollers, other programmable circuits, combinations of the above, etc. Generally, the processor 5604 may act as the computational center of the non-contact current measurement system 5600 by supporting the execution of instructions and reading and writing data to one or more storage devices, I / O interfaces, and communication systems.

[0227] The non-contact current measurement system 5600 may also include a memory 5610 communicatively coupled to the processor 5604, the memory 5610 storing at least one of instructions or data. The memory 5610 may include one or more solid-state memories, such as flash memory or solid-state drives (SSDs), that provide non-volatile storage of computer-readable instructions, data structures, program modules, and other data for the non-contact current measurement system 5600. Although not shown, the non-contact current measurement system 5600 may employ other non-transitory computer-readable or processor-readable media, such as a hard disk drive, an optical disk drive, or a memory card media drive.

[0228] The non-contact current measurement system 5600 can include a user interface 5612, which can include any number of inputs 5613 (e.g., buttons, dials, switches, touch sensors, touch screens, trigger switches, selectors, rotary switches) and any number of outputs 5614 (e.g., displays, LEDs, speakers, buzzers). Non-limiting examples of display devices include: Examples of such display devices include liquid crystal display (LCD) devices, light emitting diode (LED) devices, and / or organic light emitting diode (OLED) devices. The user interface 5612 may include a touch screen, which may be any type of touch screen now known or later developed. For example, the touch screen may be a capacitive, infrared, resistive, or surface acoustic wave (SAW) device. In implementations in which the non-contact current measurement system 5600 includes a display, the display can show a readout and / or a waveform indicative of at least one characteristic (e.g., magnitude, frequency) of the current flowing through the insulated wire under test.

[0229] In operation, the processor 5604 receives sensor signals from the position feedback sensor 5608 and the current sensor 5602 to obtain clamp position and current measurements, respectively. As discussed above, the clamp position measurements may be indicative of the diameter of the insulated wire under test, and the current sensor signals may be indicative of at least one characteristic (e.g., magnitude) of the current flowing through the insulated wire. As discussed above, the processor 5604 may utilize such measurements to determine at least one characteristic of the current flowing through the insulated wire under test, such as the magnitude and / or frequency of the current flowing through the insulated wire.

[0230] The processor 5604 may provide a readout of one or more of the measured or determined characteristics (e.g., current magnitude, current frequency, diameter of insulated wire) and may provide a graphical representation of the one or more characteristics, such as a waveform, a harmonic bar graph, etc.

[0231] To communicate with one or more external processor-based devices, the non-contact current measurement system 5600 may include one or more wired and / or wireless communication interfaces 5616. Non-limiting examples of wireless communication interfaces include Wi-Fi, Bluetooth, Bluetooth Low Energy, Zigbee, 6LoWPAN, Optical IR, WirelessHART, etc. Non-limiting examples of wired communication interfaces include USB, Ethernet, PLC, HART, MODBUS, FireWire, Thunderbolt, etc.

[0232] In addition to sending data to an external device, in at least some implementations, the non-contact current measurement system 5600 can receive at least one of data or instructions (e.g., control instructions) from an external device via the wired and / or wireless communication interface 5616.

[0233] In at least some implementations, the non-contact current measurement system 5600 may not include a display, but instead may be used as a sensor to remotely monitor electrical equipment via an external processor-based device. Such processor-based devices may include various types of devices, such as smartphones, tablet computers, laptop computers, wearable computers, servers, cloud computers, etc. The external processor-based device may include a display that shows data collected by the non-contact current measurement system 5600 over a period of time (e.g., minutes, hours, days, weeks).

[0234] In at least some implementations, the non-contact current measurement system can include one or more additional electrical sensors 5618 communicatively coupled to the processor 5604. Such electrical sensors 5618 can include a voltage sensor capable of sensing a voltage, a resistive sensor capable of sensing a resistance, a capacitive sensor capable of sensing a capacitance, or the like. In such implementations including one or more additional sensors 5618, the non-contact current measurement system 5600 can function as a multimeter providing multiple electrical properties (e.g., current, voltage, power, resistance, capacitance).

[0235] In at least some implementations, the electrical sensor 5618 can include a reference signal sensor operative to detect the thickness of the insulation of the insulated wire under test. Various exemplary reference signal sensors are discussed above with reference to FIGS. 1A-15. In such implementations, the adjustable clamp assembly 5606 and the position feedback sensor 5608 can be used to determine the overall diameter of the insulated wire, and the reference signal sensor 5618 can utilize the reference signal method discussed above to determine the thickness of the insulation of the insulated wire. Using the overall diameter of the insulated wire determined by the adjustable clamp assembly 5606 and the position feedback sensor 5608 and the determined insulation thickness determined by the reference signal sensor 5618, the non-contact current measurement system can automatically determine a diameter of the conductor of the insulated wire, the diameter of the conductor of the insulation of the insulated wire being equal to the overall diameter of the insulated wire reduced by two times the determined insulation thickness. The determined diameter of the conductor can then be used together with the detected magnetic field to determine the magnitude of the current flowing through the insulated wire.

[0236] The foregoing detailed description has described various implementations of devices and / or processes through the use of block diagrams, schematic diagrams, and examples. To the extent that such block diagrams, schematic diagrams, and examples include one or more functions and / or operations, it will be understood by those skilled in the art that each function and / or operation within such block diagrams, flow diagrams, or examples can be individually and / or collectively performed by a wide range of hardware, software, firmware, or substantially any combination thereof. In one implementation, the subject matter can be performed via an application specific integrated circuit (ASIC). However, those skilled in the art will recognize that the implementations disclosed herein may equivalently be implemented, in whole or in part, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more controllers (e.g., microcontrollers), as one or more programs running on one or more processors (e.g., microprocessors), as firmware, or within standard integrated circuits, as substantially any combination thereof, and that designing and / or writing the circuitry for the software and / or firmware is well within the knowledge of one of ordinary skill in the art in light of this disclosure.

[0237] Those skilled in the art will recognize that many of the methods or algorithms described herein may employ additional acts, may omit certain acts, and / or may perform acts in a different order than specified. As an example, in at least some implementations, the non-contact measurement system may not utilize a processor to execute instructions. For example, the non-contact measurement system may be hardwired to provide some or all of the functionality discussed herein. Further, in at least some implementations, the non-contact measurement system may not utilize a processor to cause or initiate the different functionality discussed herein.

[0238] Moreover, those skilled in the art will recognize that the mechanisms taught herein can be distributed as program products in a variety of forms, and the exemplary implementations apply equally regardless of the particular type of signal-bearing medium used to actually effect the distribution, including, but not limited to, the following: floppy disks, hard disk drives, CD-ROMs, digital tape, and recordable forms of media such as computer memory. However, the present invention is not limited to the above.

[0239] The various implementations described above can be combined to provide further implementations. To the extent such implementations do not conflict with the specific teachings and definitions herein, U.S. Provisional Patent Application No. 62 / 421,124, filed November 11, 2016, U.S. Patent Application No. 15 / 345,256, filed November 7, 2016, U.S. Patent Application No. 15 / 412,891, filed January 23, 2017, and U.S. Patent Application No. 15 / 413,025, filed January 23, 2017 are incorporated herein by reference in their entirety.

[0240] These and other changes to the implementations can be made in light of the above description. Generally, in the following claims, the terms used should not be construed to limit the claims to the specific implementations disclosed in the specification and claims, but should be construed to include all possible implementations along with the full scope of equivalents to which such claims are entitled. Thus, the claims are not limited by the disclosure.

Claims

1. 1. A non-contact measurement system for measuring a voltage or a current in an insulated electric wire without making direct electrical contact with the insulated electric wire, comprising: a housing including a front end including a first end portion, a second end portion, and a receiving portion between the first end portion and the second end portion, and a gripping portion to be gripped by an operator of the non-contact measurement system during the measurement; at least one processor disposed within the housing; a conductive voltage sensor physically coupled to the housing and selectively positionable proximate to the insulated wire, the voltage sensor operative to capacitively couple to the insulated wire without direct electrical contact therewith to generate a voltage sensor signal indicative of a voltage within the insulated wire; a conductive internal ground guard at least partially surrounding the voltage sensor and directly electrically coupled to an internal electrical ground of the non-contact measurement system, the conductive internal ground guard being sized and dimensioned to shield the voltage sensor from stray currents; a conductive reference shield surrounding at least a portion of the housing and not in direct electrical contact with the conductive internal ground guard, the conductive reference shield being sized and dimensioned to reduce current flow between the conductive internal ground guard and an external ground, the conductive reference shield capacitively coupling to the external ground; a common mode reference voltage source electrically coupled between the conductive internal ground guard and the conductive reference shield, the common mode reference voltage source generating, in operation, an AC reference voltage having a reference frequency; a first alignment feedback sensor at the first end portion and a second alignment feedback sensor at the second end portion, each of the first and second alignment feedback sensors operatively coupled to the at least one processor, and in operation, each of the first and second alignment feedback sensors detects a voltage in an insulated wire when the insulated wire is positioned proximate the first and second alignment feedback sensors and, in response, generates an alignment feedback sensor signal indicative of a current alignment of the insulated wire relative to the receiver; an indicator device operatively coupled to the at least one processor, wherein in operation the at least one processor receives the alignment feedback sensor signal and causes the indicator device to provide an alignment indication to a user of the non-contact measurement system based at least in part on the alignment feedback sensor signal, the alignment indication indicating a degree of alignment of the insulated wire relative to the receiving portion; a current sensor disposed adjacent the front end of the housing for sensing, in operation, a current in the insulated wire without making direct electrical contact with the insulated wire; During operation, the at least one processor: receiving from the voltage sensor a voltage sensor signal acquired by the voltage sensor during a measurement time interval, the voltage sensor signal being indicative of the voltage in the insulated wire; receiving from the current sensor a current sensor signal acquired by the current sensor during the measurement time interval, the current sensor signal being indicative of the current in the insulated wire; A non-contact measurement system that determines at least one alternating current (AC) electrical parameter based at least in part on the voltage sensor signal and the current sensor signal, and also based on a body capacitance, which is the capacitance of the operator to ground when the operator grasps the gripping portion of the non-contact measurement system.

2. The non-contact measurement system of claim 1 , wherein the current sensor comprises a magnetic field sensor.

3. 3. The non-contact measurement system of claim 1, wherein the voltage sensor, in operation, senses a voltage in the insulated wire having a frequency that is different from the reference frequency of the AC reference voltage generated by the common mode reference voltage source of the non-contact measurement system without making direct electrical contact with the insulated wire.

4. The non-contact measurement system of claim 1 , wherein the at least one AC electrical parameter comprises at least one of power, phase, frequency, harmonics or energy.

5. The non-contact measurement system of claim 1 , wherein, during operation, the at least one processor determines a plurality of AC electrical parameters based at least in part on the voltage sensor signal and the current sensor signal.

6. 6. The non-contact measurement system of claim 1 , further comprising a display operably coupled to the at least one processor, wherein, during operation, the at least one processor causes the display to indicate the at least one AC electrical parameter.

7. The non-contact measurement system of claim 6 , wherein, during operation, the at least one processor causes the display to show at least one of a waveform or a graph associated with the at least one AC electrical parameter.

8. 8. The non-contact measurement system of claim 1, further comprising a communication interface operatively coupled to the at least one processor, wherein during operation, the at least one processor sends data to at least one external device via the communication interface, the data relating to at least one of the voltage sensor signal, the current sensor signal, or the at least one AC electrical parameter.

9. The non-contact measurement system of claim 8 , wherein the communication interface comprises a wireless communication interface operable to wirelessly transmit the data to the at least one external device.

10. A non-contact measurement system according to any preceding claim, wherein the indicator device comprises at least one of a visual indicator device or an audible indicator device.

11. 6. The non-contact measurement system of claim 1, wherein the indicator device includes at least one of a display or a plurality of lights, and wherein, during operation, the at least one processor causes the indicator device to provide the alignment indication to the user including a plurality of colors, each of the plurality of colors corresponding to a different degree of alignment of the insulated wire with respect to the receiving portion.

12. 12. The non-contact measurement system of claim 1, wherein, during operation, the at least one processor causes the indicator device to provide a color-coded indication of measurement accuracy based at least in part on the alignment feedback sensor signal.

13. 1. A method performed by a non-contact measurement system for measuring voltage or current in an insulated electrical wire without direct electrical contact with the insulated electrical wire, the non-contact measurement system comprising: a housing; a voltage sensor physically coupled to the housing and selectively positionable in proximity to the insulated electrical wire without galvanically contacting the insulated electrical wire; a conductive internal ground guard at least partially surrounding and galvanically insulated from the voltage sensor, the conductive internal ground guard sized and dimensioned to shield the voltage sensor from stray currents; and a conductive reference shield surrounding at least a portion of the housing and galvanically insulated from the conductive internal ground guard, the conductive reference shield sized and dimensioned to reduce current flow between the conductive internal ground guard and an external ground, receiving, via at least one processor disposed within the housing of the non-contact measurement system, from at least one of a first alignment feedback sensor disposed proximate a first end portion of the front end of the housing of the non-contact measurement system and a second alignment feedback sensor disposed proximate a second end portion of the front end of the housing of the non-contact measurement system, an alignment feedback sensor signal indicative of a current alignment of the insulated wire with respect to a receptacle at the front end between the first end portion and the second end portion, the alignment feedback sensor signal being generated in response to detecting a voltage in the insulated wire when the insulated wire is positioned proximate the receptacle, the housing including, in addition to the front end, a gripping portion to be gripped by an operator of the non-contact measurement system during the measurement; causing, via the at least one processor, an indicator device disposed on a surface of the housing of the non-contact measurement system to provide an alignment indication to a user of the non-contact measurement system based at least in part on the alignment feedback sensor signal, the alignment indication indicating a degree of alignment of the insulated wire relative to the receiving portion; causing a common mode reference voltage source electrically coupled between the conductive internal ground guard and the conductive reference shield to generate an alternating current (AC) reference voltage having a reference frequency; sensing, via the voltage sensor disposed within the housing of the non-contact measurement system, a signal indicative of a voltage in the insulated wire during a measurement time interval without making direct electrical contact with the insulated wire; sensing, during the measurement time interval, a signal indicative of a current in the insulated wire via a current sensor disposed within the housing of the non-contact measurement system without making direct electrical contact with the insulated wire; and determining, via the at least one processor, at least one alternating current (AC) electrical parameter based at least in part on the sensed voltage and the sensed current, and also based on a body capacitance, which is the capacitance of the operator to ground when the operator grasps the gripping portion of the non-contact measurement system.

14. 14. The method of claim 13, wherein sensing the voltage includes sensing the voltage using a capacitive divider voltage sensor, and sensing the current includes sensing the current using a magnetic field sensor.

15. 15. The method of claim 13 or 14, wherein determining at least one AC electrical parameter includes determining at least one of power, phase, frequency, harmonics, or energy based at least in part on the sensed voltage and the sensed current.

16. 16. The method of claim 13, further comprising presenting an indication of the at least one AC electrical parameter to a user of the non-contact measurement system.

17. 1. A non-contact measurement system for measuring a voltage or a current in an insulated electric wire without making direct electrical contact with the insulated electric wire, comprising: a housing including a front end including a first end portion, a second end portion, and a receiving portion between the first end portion and the second end portion, and a gripping portion to be gripped by an operator of the non-contact measurement system during the measurement; a first alignment feedback sensor at the first end portion and a second alignment feedback sensor at the second end portion, wherein in operation, the first and second alignment feedback sensors each detect a voltage in an insulated wire when the insulated wire is positioned proximate the first and second alignment feedback sensors and, in response, generate an alignment feedback sensor signal indicative of a current alignment of the insulated wire with respect to the receiver; An indicator device; a voltage sensor disposed adjacent the front end of the housing for sensing, during operation, a voltage sensor signal indicative of a voltage in the insulated wire without making direct electrical contact with the insulated wire; a current sensor disposed adjacent the front end of the housing for, during operation, sensing a current sensor signal indicative of current in the insulated wire without making direct electrical contact with the insulated wire; at least one processor within the housing; a conductive internal ground guard at least partially surrounding the voltage sensor and directly electrically coupled to an internal electrical ground of the non-contact measurement system, the conductive internal ground guard being sized and dimensioned to shield the voltage sensor from stray currents; a conductive reference shield surrounding at least a portion of the housing and not in direct electrical contact with the conductive internal ground guard, the conductive reference shield being sized and dimensioned to reduce current flow between the conductive internal ground guard and an external ground, the conductive reference shield capacitively coupling to the external ground; a common mode reference voltage source electrically coupled between the conductive internal ground guard and the conductive reference shield, the common mode reference voltage source generating, in operation, an AC reference voltage having a reference frequency; During operation, the at least one processor: receiving the alignment feedback sensor signal indicative of a current alignment of the insulated wire relative to the receiving portion; causing the indicator device to provide an alignment indication indicative of a degree of alignment of the insulated wire relative to the receiving portion based at least in part on the alignment feedback sensor signal; receiving from the voltage sensor a voltage sensor signal acquired by the voltage sensor during a measurement time interval, the voltage sensor signal being indicative of the voltage in the insulated wire; receiving from the current sensor a current sensor signal acquired by the current sensor during the measurement time interval, the current sensor signal being indicative of the current in the insulated wire; A non-contact measurement system that determines at least one alternating current (AC) electrical parameter based at least in part on the voltage sensor signal and the current sensor signal, and also based on a body capacitance, which is the capacitance of the operator to ground when the operator grasps the gripping portion of the non-contact measurement system.

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