Enhanced differential sensor winding mode

Abstract

The invention provides an assembly guide of a current transformer. A housing is sized and shaped to receive a core of a current transformer, the housing having a plurality of grooves formed in an outer surface. The grooves are spaced apart according to a predetermined winding distribution pattern such that winding portions wound around the core and the housing are positioned in selected grooves of the housing according to the predetermined winding distribution pattern. The assembly guide also includes a snap-fit outer housing including a pin extending along a central axis of the housing. The pin is sized and shaped to fit in an opening in the core and is configured to hold a conductor in a predetermined position within the core opening.

Description

Background Technology

[0001] This disclosure relates to electrical protection devices employing differential sensors, such as current transformers. More specifically, this disclosure relates to apparatus, systems, and methods for improving the performance and reliability of current transformers.

[0002] Differential protection operates based on Kirchhoff's current law, which stipulates that the sum of the currents flowing into the node is zero. If the primary current equals the secondary current, the current law is verified, and there is no fault in the transformer.

[0003] Conventional current transformers (CTs) used to detect ground faults can have non-uniform coils and experience asymmetrical magnetic coupling with the relative positions of two or more conductors passing through their core. This asymmetry can lead to false indications about the presence of a ground fault, for example, because a current is induced in the CT even if the currents on the two lines are likely substantially the same and should theoretically cancel each other out. Therefore, the induced current in the CT sensing coil can falsely indicate the presence of a ground fault even when there is no actual current mismatch between the conductors.

[0004] Conventional systems utilize complex and expensive equipment manufacturing and component testing processes. For example, individual electronic components of the device may not be tested until the device is fully assembled, resulting in a high failure rate for assembled devices. Furthermore, existing testing systems may exhibit high levels of inconsistency in detecting ground faults with high winding asymmetry under rated load conditions. Detecting test failures only at the end of the manufacturing process, leading to rework or scrapping of devices and components, significantly increases the testing costs of circuit breaker sensors and assembled circuit breaker devices, and substantially extends their testing cycle.

[0005] Co-assigned U.S. Patent Application No. 18 / 539,141 discloses a sensor for screening a device under test. The sensor includes a body having a plurality of conductors, a rotating section, a probe associated with the rotating section, the probe being configured to receive at least a portion of one or more of the plurality of conductors, and a base having at least one terminal, the base being configured to be coupled to the device under test and to allow at least a portion of the probe to pass through an opening in the device under test.

[0006] Commonly assigned U.S. Patent Application No. 18 / 125,116 discloses a current transformer for a Ground Fault Circuit Interrupter (GFCI) comprising a core having a closed-loop shape and a sensing coil wound around the core, the closed-loop shape having a first side, a second side, and a core opening, the sensing coil being configured to be magnetically coupled to a plurality of conductors passing through the core opening. The current transformer also includes a first magnetic shield disposed above the sensing coil on the first side of the core, and a second magnetic shield disposed above the sensing coil on the second side of the core.

[0007] The challenges of assembling advanced circuit breakers and similar devices can affect sensor performance. For example, if the current path is close to the sensor assembly, the current generates an electromagnetic mode that causes an imbalance in the output voltage during a load-to-ground fault event (load current + ground fault). As a result, the sensor output voltage at a particular ground fault location deviates from the calibrated output voltage value.

[0008] Such conventional methods and systems are generally considered satisfactory for their intended purposes. However, improvements are still needed in the art. This disclosure provides a solution to this need. Summary of the Invention

[0009] Various aspects of this disclosure reduce inconsistencies in the winding distribution of differential sensors (including current transformers) by fixing the coil pattern in a selected groove and balancing the magnetic pattern and providing precise positioning of the conductors and coils.

[0010] In one aspect, the current transformer includes a core having a channel passing through it, the channel being configured to receive one or more conductors. The current transformer also includes a housing and a sensing winding, the housing being sized and shaped to receive the core, and the sensing winding being wound around the core and housing. The housing has a plurality of grooves formed in its outer surface. The grooves are spaced apart according to a predetermined winding distribution pattern. The sensing winding is configured to be magnetically coupled to the conductor passing through the core channel and to generate a fault signal in response to a ground fault condition in the conductor. The sensing winding is wound around the core and housing such that portions of the sensing winding are positioned in selected grooves in the housing according to a predetermined winding distribution pattern.

[0011] On the other hand, the assembly guide for the current transformer includes a housing and a plurality of recesses. The housing is sized and shaped to receive the core of the current transformer, and the recesses are formed in the outer surface of the housing. The recesses are spaced apart according to a predetermined winding distribution pattern, such that portions of the sensing winding wound around the core and housing are positioned in selected recesses of the housing according to the predetermined winding distribution pattern.

[0012] In another aspect, the assembly guide for a current transformer includes a housing configured to receive the core and windings of the current transformer. The core has a channel passing through it, configured to receive one or more conductors. The assembly guide also includes pins extending along the central axis of the housing. The pins are sized and shaped to fit within the core channel and are configured to receive and hold the received conductors in a predetermined position within the core channel.

[0013] Other objects and features of the invention will be apparent in part and set forth herein in part. Attached Figure Description

[0014] Figure 1 This is a perspective view of a current transformer according to an embodiment.

[0015] Figure 2 This is a perspective view of a ground fault circuit interrupter according to an embodiment, wherein a current transformer is provided.

[0016] Figure 3 This is a perspective view of a current transformer with a conductor passing through a core opening, according to an embodiment.

[0017] Figure 4A A shielded current transformer assembly according to an embodiment is shown, wherein the cover has been removed to expose the interior of the assembly.

[0018] Figure 4B This is a cross-sectional view of a shielded current transformer according to an embodiment.

[0019] Figures 5A to 5E The diagram shows components of a metal shield for use with a current transformer, according to an embodiment.

[0020] Figures 6A to 6E A component of a metal shield for use with a current transformer, according to another embodiment, is shown.

[0021] Figure 7A and 7B A component of a metal shielding used with a current transformer according to yet another embodiment is shown.

[0022] Figure 8 This is a diagram of magnetic flux lines smoothed by the apertures of a metal shield, according to an embodiment.

[0023] Figure 9A and 9B A test system for screening devices under test is shown according to an embodiment.

[0024] Figure 10 This is a schematic diagram of an exemplary test setup according to an embodiment.

[0025] Figures 11A to 11D A sequence of tests on the device under test at multiple radial positions is shown according to an embodiment.

[0026] Figure 12 This is a flowchart illustrating an exemplary process for screening devices under test.

[0027] Figure 13A and 13B This is a schematic diagram of an exemplary test setup according to an embodiment.

[0028] Figure 14 This is a perspective view of an assembly guide for a current transformer according to an embodiment.

[0029] Figure 15A and 15B An example of a wound core according to an embodiment is shown.

[0030] Figure 16 This is a perspective view of a snap-fit ​​housing for a current transformer according to an embodiment.

[0031] Figure 17 This is a perspective view of the pins of an assembly guide for positioning a conductor passing through the core opening of a current transformer, according to an embodiment.

[0032] Figures 18A to 18C The core of a current transformer, positioned on the pin of an assembly guide according to an embodiment, is shown.

[0033] Throughout the accompanying drawings, corresponding reference numerals denote corresponding parts. Detailed Implementation

[0034] The features and other details of the concepts, systems, and techniques sought to be protected herein will now be described in more detail. It should be understood that any specific embodiments described herein are shown by way of illustration and are not intended to limit this disclosure and the concepts described herein. Features of the subject matter described herein may be employed in various embodiments without departing from the scope of the sought-protected concepts.

[0035] Figure 1 An electrical protection device 210 according to aspects of this disclosure is shown (see [reference]). Figure 2This is an embodiment of a current transformer (CT) 130. The device can be a device or part thereof configured to perform at least one operation, including a miniature circuit breaker (MCB), ground fault circuit interrupter (GFCI), or other electronic device or part thereof as described in various embodiments, or it can be a device or part thereof configured to perform one or more operations corresponding to a GFCI. CT 130 can be any suitable shape (e.g., a polygonal closed shape, such as a rectangular closed shape). For example, CT 130 can be a circular or annular closed shape as shown in the figure.

[0036] In some embodiments, Figure 1 The CT 130 includes one or more of a body 132, a first terminal 134 (e.g., having a plurality of downwardly extending pins), a second terminal 136 (e.g., having a first pin 136a, a second pin 136b, a third pin 136c, and a fourth pin 136d, respectively), a housing 138, and / or an opening 140. In some embodiments, and in various embodiments, the first terminal 134 and the second terminal 136 may include a plurality of pins. The first terminal 134 and the second terminal 136 may be connected together such that each pin 136a, b, c, d of the second terminal 136 is connected to a corresponding pin of the first terminal 134. In some embodiments, the first pin 136a and the second pin 136b may be connected to a sensing winding or coil 410 contained within the housing 138 of the CT 130 (see...). Figure 4A and 4B The opposite end of CT 130. The opening 140 of CT 130 can be configured to allow one or more conductors 220 (see...). Figure 2 ( ) and / or other conductors or components (or portions thereof) pass through it at least partially. In the various embodiments described herein, Figure 1 The CT 130 may include a shield 430 (see Figure 4A and 4B ).

[0037] According to at least one aspect of this disclosure, reference to Figure 2 GFCI 210 includes a conductor 220 (e.g., a line, neutral, or ground wire) passing through a current transformer (such as CT 130 disclosed herein). The conductor 220 passes through, for example, an opening 140. Any suitable number of conductors 220 (e.g., three as shown in the figure) is contemplated herein for any suitable application. As described above, CT 130 includes a core 412 wound around CT 130 (see...). Figure 4A and 4BThe sensing coil is configured to be magnetically coupled to the line conductor and neutral conductor passing through the opening 140. The GFCI 210 may include a test winding or coil wound (e.g., partially) around the core 412 of the CT 130 and configured to be magnetically coupled to the sensing coil through the core 412 to provide a test signal to the sensing coil.

[0038] Now for reference Figure 3 The electrical protection device (e.g., GFCI 210) includes a plurality of conductors 220 (e.g., lines, neutral, or ground). At least a portion of one or more of the conductors 220 is configured to pass through an opening 140 of the CT 130. Although shown as having three conductors 220, it should be understood that, without departing from the spirit and scope of this disclosure, in various embodiments any number of conductors may be configured to pass through at least a portion of the opening 140 of the CT 130.

[0039] Figure 3 Partial depictions of elements of a sensor component (e.g., CT 130) according to various aspects of this disclosure are shown, the sensor component having multiple current paths passing through it. Figure 3 In the example, current flows in L1 and L2, where I1 = I2. Figure 3 An example of a CT 130 with a non-uniform and random winding distribution and effects from nearby conductor 220 is shown. This is especially relevant if conductor 220 is installed near CT 130 during the assembly of the electrical protection device (e.g., Figure 3 As shown in the example, the current in conductor 220 generates an electromagnetic mode that may cause an output voltage imbalance during a load-to-ground fault event (load current + ground fault). As a result, the sensor output voltage value of CT 130 at a specific ground fault deviates from the calibrated sensor output voltage value. The effect of the random distribution of the coil, combined with the magnetic influence (encirclement effect) of the nearby conductor 220, results in an output voltage Vout with a non-zero amplitude. Vout can have a considerably high value compared to the ideal case (uniform winding distribution).

[0040] Figure 4A and 4B A current transformer 130 for a GFCI 210 according to at least one aspect of this disclosure is shown. For example... Figure 4AAs shown, the cover of CT 130 is removed to expose its interior. CT 130 may include a sensing coil 410 wound around a core 412 configured to be magnetically coupled to a line conductor and a neutral conductor passing through opening 140. The sensing coil 410 is also configured to generate a fault signal in response to a ground fault condition in conductor 220. In the illustrated embodiment, the core 412 has a channel passing through it corresponding to opening 140. CT 130 may also include a test coil 414 partially wound around the core 412 and configured to be magnetically coupled to the sensing coil 410 through the core 412 to provide a test signal to the sensing coil 410 in response to a test signal excitation applied to the test coil 414. Figure 4B The metal shielding 430, which will be described in more detail below, is further shown.

[0041] Figure 5A and 5B A magnetically conductive shield 430 is shown, configured to receive a core 412, a sensing coil 410, and a test coil 414. In an embodiment, the shield 430 is made of a ferromagnetic material (e.g., 1010 steel alloy, 1018 steel alloy). The shield 430 is configured to shield the core 412 from external magnetic field lines, such as those generated outside the CT 130 by the current in conductor 220. Nearby magnetic fields are absorbed by the shield 430. Therefore, magnetic flux lines do not cross the winding core 412, thereby preventing deviation from the output voltage of the CT 130. Differential sensors such as the CT 130 equipped with the shield 430 to reduce crosstalk electromagnetic effects from nearby conductors offer improved performance and reliability.

[0042] A shield 430 according to one or more embodiments includes an outer portion and an inner portion located inside the outer portion. The outer portion and the inner portion of the shield 430 define a space therebetween in which the core 412, sensing coil 410, and test coil 414 are received. In the illustrated embodiment, the outer portion of the shield 430 includes a cup-shaped housing 510 and a washer-shaped cap 512, the cup-shaped housing 510 being sized and shaped to receive... Figure 5A The core 412 and coils 410 and 414, and the washer-shaped cap 512 are used for sealing. Figure 5B The housing 510 is a core. The internal portion of the housing 510 includes an eyelet 514, such that the housing 510 and the eyelet 514 each comprise an outer cylinder and a concentric inner cylinder, respectively. When the core 412 is received within the shield 430, the core channel is assembled around the eyelet 514. In an embodiment, an insulator 702 (see FIG. 7) separates the core 412 from the inner surface of the housing 510. Advantageously, improved sensor performance can be achieved by redirecting the magnetic flux lines from the sensor core to the shield. This reduces crosstalk, which in turn reduces output voltage sensor variations and results in an improved GF threshold.

[0043] Now for reference Figures 5C to 5E The CT 130 also includes a sheath 604 covering the shield 430. The sheath 604 includes a first locking feature 606, and the shield 430 includes a second locking feature 608. The second locking features 606 and 608 engage with each other in a mating relationship to prevent rotation of the shield 430 relative to the sheath 604. According to one or more embodiments of the present disclosure, the first locking feature 606 of the sheath 604 includes a protrusion, and the second locking feature 608 of the shield 430 includes a groove sized and shaped to receive the protrusion.

[0044] In an alternative embodiment, the outer portion of the shield 430 includes a cup-shaped housing 510 and a washer-shaped cap 512, the cup-shaped housing 510 being sized and shaped to receive... Figure 6A The core 412 and coils 410 and 414, and the washer-shaped cap 512 are used for sealing. Figure 6B The housing 510 is located within the shield 430. In this embodiment, the internal portion of the shield 430, namely the eyelet 514, is integrated with the washer-shaped cap portion 512, rather than with the housing 510. Figures 6C to 6E The cover is shown Figure 6A and 6B The shield 430 has a sheath 604. The sheath 604 includes a first locking feature 606, and the shield 430 includes a second locking feature 608. The second locking features 606 and 608 engage with each other in a mating relationship to prevent the shield 430 from rotating relative to the sheath 604. According to one or more embodiments of the present disclosure, the first locking feature 606 of the sheath 604 includes a protrusion, and the second locking feature 608 of the shield 430 includes a groove sized and shaped to receive the protrusion.

[0045] Figure 7A and 7B A current transformer assembly according to another alternative embodiment is shown, wherein the eye 514 is integrated with the washer cap 512 instead of with the housing 510.

[0046] This disclosure provides a shield 430, which is designed as a housing 510 configured to receive a wound core 412, with insulation between the wound core and the metal shield 430 via an insulator 702 (e.g., a plastic housing).

[0047] The aperture 514 advantageously smooths out specific magnetic flux patterns, such as... Figure 8 As shown in the schematic diagram, the eyelet 514 of the shield 430 guides the magnetic flux lines around the eyelet core before passing through the core 412.

[0048] There are complex challenges in properly selecting sensors to accurately reconstruct environmental conditions (e.g., MCB current path components). See now, according to at least one aspect of this disclosure. Figure 9A and Figure 9B A system 910 for screening a device under test (DUT) 912 for crosstalk is shown. The system 910 includes a mounting clamp or base 914 having at least one terminal 1002 (see [link to documentation]). Figure 10 The base 914 is configured to be coupled to the DUT 912 (such as CT 130) via terminal 1002 and receives the output signal Vout during screening. The system 910 also includes a rotatable support 916 to which an external conductor 918 is attached. The external conductor 918 represents a "universal" current path close to the DUT 912 and forms a loop 920 with a U-shape, sized such that the loop 920 can rotate freely around the DUT 912 without contact. When the DUT 912 is connected to the base 914, the loop 920 is configured to be positioned near the DUT 912, and the rotatable support 916 allows the loop 920 to rotate through multiple radial positions during screening. When the external conductor 918 is energized, the current in the loop 920 generates a magnetic field near the DUT 912.

[0049] Now for reference Figure 10 The test module 1004, connected to the base 914, receives an output signal Vout during screening. The test module 1004 includes a data acquisition device that receives and responds to the output signal to acquire and process measurement data at each of a plurality of radial positions of the rotatable ring 920. In an embodiment, the test module 1004 also includes signal conditioning circuitry for amplifying and conditioning the output signal. The test module then compares the output signal of the DUT 912 when the external conductor 918 is not energized with the output signal of the DUT 912 when the external conductor 918 is energized. Based on this comparison, the test module 1004 screens the sensitivity of the DUT 912 to the magnetic winding effect and outputs, for example, a pass or fail signal. Advantageously, the test system 910 enables testing of the effectiveness of the protective shielding around the wound core (e.g., shielding 430 around the core 412).

[0050] In one embodiment, system 910 is combined with a winding distribution test apparatus, such as that disclosed in commonly assigned U.S. Patent Application No. 18 / 539,141. The winding distribution test apparatus includes a probe configured to receive at least a portion of one or more conductors 220, wherein a base 914 allows at least a portion of the probe to pass through a core opening 140. Multiple tests can be combined: winding distribution, output voltage, and crosstalk. Combining several tests in the same fixture optimizes test time.

[0051] Figures 11A to 11DA sequence of DUT 912 tests at multiple radial locations according to one or more embodiments is shown.

[0052] This disclosure describes various methods for performing screening of DUT 912. Figure 12 An exemplary process 1200 for screening DUT 912 is shown. Starting at 1202, an external conductor 918 is energized with a rated current. At 1204, DUT 912 is positioned relative to a rotatable external conductor 918, which forms a loop 920 close to DUT 912. As described above, the current in loop 920 generates a magnetic field near DUT 912. The method also includes rotating the external conductor 918 relative to DUT 912 through multiple radial positions and obtaining subsequent output signals from DUT 912 at these radial positions. Step 1206 refers to the measurement operation of process 1200, after which the external conductor 918 is de-energized at 1208. At 1210, test module 1004 calculates device properties based on the measurement data. For example, test module 1004 compares the initial output signal of DUT 912 when the external conductor 918 is not energized with the subsequent output signal of DUT 912 when the external conductor 918 is energized, and determines the sensitivity of DUT 912 to magnetic winding effects based on this comparison. Additionally, at 1212, a pass signal or a failure signal can be generated based on comparing the subsequent output signal with a predetermined range of acceptable values.

[0053] Figure 13A and 13B This is a schematic diagram of an exemplary test setup according to an embodiment of the present disclosure.

[0054] Maintaining and controlling proper winding pitch and symmetry is difficult with closed-core differential sensors. (See reference now.) Figure 14 Various aspects of this disclosure relate to assembly guides that address winding distribution issues in differential current transformers by adding specific grooves to a unique plastic housing. Improved winding distribution enhances sensor performance. Figure 14The assembly guide includes a housing 1402, which is sized and shaped to receive the core 412 of the CT 130. As shown, the housing 1402 has a plurality of grooves 1404 formed in its outer surface. In the illustrated embodiment, the grooves 1404 are formed in the top or end surfaces of the housing 1402. The grooves 1404 are spaced apart according to a predetermined winding distribution pattern, such that a portion of the sensing winding 410 wound around the core 412 and the housing 1402 is positioned in a selected groove 1404 according to the predetermined winding distribution pattern. Similarly, the grooves 1404 are spaced apart according to a predetermined winding distribution pattern, such that a portion of the test winding 414 wound around the core 412 and the housing 1402 is positioned in other selected grooves 1404 of the housing according to the predetermined winding distribution pattern. In this way, the assembly guide reduces winding distribution inconsistencies by fixing the coil pattern, which improves the ground fault threshold.

[0055] Figures 15A and 15B show two exemplary cores 412 with windings 410 and 414 wound around them, the winding pattern conforming to a preset winding distribution pattern. The specific magnetic flux pattern around the toroidal core has the following characteristics: the magnetic field lines form closed loops, completely encircling the core, roughly forming concentric circles perpendicular to the direction of current flow in the windings; due to the symmetrical design of the toroidal structure, the magnetic flux is mainly concentrated inside the core, thereby minimizing leakage flux outside the toroid. To achieve a balanced magnetic pattern, geometric positioning of the conductors is required. Furthermore, by grouping the coils near areas of high magnetic flux density, the sensor can obtain a balanced output voltage.

[0056] Now for reference Figure 16 Various aspects of this disclosure relate to another assembly guide for current transformers, used in place of... Figure 14 Assembly guide or other than Figure 14 This assembly guide is used in addition to other components. According to this embodiment, the assembly guide includes a housing 1602, in which a core 412, a housing 1402, and windings 410, 414 are housed. The housing 1602 includes two parts that engage with each other in a snap-fit ​​relationship. One component of the housing 1602 includes an axially extending pin 1604, such as... Figure 17 As shown. The size and shape of the pin 1604 are designed to fit within the core opening 140 and are configured to receive the conductor 220 and hold the received conductor in a predetermined position within the core opening 140 to control the magnetic field mode by positioning the current conductor in a specific location. In an embodiment, the pin 1604 is Y-shaped and configured to receive three conductors 220.

[0057] Figure 18A The winding core 412 positioned on pin 1604 is shown. Figure 18BSimilarly, a wound core 412 is shown positioned on the pin 1604 in addition to the conductor 220 which passes through the opening 140 and is received in the channel defined by the pin 1604. Figure 18C yes Figure 18B A perspective view of a local current transformer assembly. Differential current transformers designed with specific winding patterns (e.g., ground fault CTs for MCBs) reduce winding distribution imbalances.

[0058] In an embodiment, housing 1402 includes a first locking feature, and outer shell 1602 includes a second locking feature, which engage with each other in a mating relationship to prevent rotation of housing 1402 and core 412 relative to outer shell 1602. The use of locking features between the wound core 412, shield 430 (if used), and snap-on cover outer shell 1602 facilitates repeatable assembly. For example, the first locking feature of the housing includes, for instance, […]. Figure 14 The protrusion 1406 is shown, and the second locking feature of the housing includes a groove (not shown, similar to the second locking feature 608 of the shield 430) that is sized and shaped to receive the protrusion 1406. The housing 402 is also configured for use with industrial winding machines.

[0059] Embodiments of this disclosure may include a dedicated computer, which includes various computer hardware as described in more detail herein.

[0060] For illustrative purposes, programs and other executable program components may be shown as discrete blocks. However, it should be recognized that such programs and components reside in different storage components of the computing device at different times and are executed by one or more data processors of the device.

[0061] Although described in conjunction with an example computing system environment, embodiments of various aspects of the invention may operate in conjunction with other dedicated computing system environments or configurations. The computing system environment is not intended to impose any limitation on the scope or functionality of any aspect of the invention. Furthermore, the computing system environment should not be construed as having any dependency or requirement relating to any one or combination of the components shown in the example operating environment. Examples of computing systems, environments, and / or configurations to which various aspects of the invention may be applied include, but are not limited to, personal computers, server computers, handheld or laptop devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, mobile phones, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the foregoing systems or devices, etc.

[0062] Embodiments of aspects of this disclosure can be described in the general context of data and / or processor-executable instructions (such as program modules) stored in one or more tangible, non-transitory storage media and executed by one or more processors or other devices. Typically, program modules include, but are not limited to, routines, programs, objects, components, and data structures that perform a particular task or implement a particular abstract data type. Aspects of this disclosure can also be practiced in a distributed computing environment, where tasks are performed by remote processing devices linked via a communication network. In a distributed computing environment, program modules can reside in both local storage media and remote storage media, including memory storage devices.

[0063] In operation, the processor, computer, and / or server can execute processor-executable instructions (e.g., software, firmware, and / or hardware), such as those shown herein, to implement aspects of the present invention.

[0064] The embodiments can be implemented using processor-executable instructions. These processor-executable instructions can be organized into one or more processor-executable components or modules on a tangible processor-readable storage medium. Furthermore, the embodiments can be implemented using any number and organization of such components or modules. For example, aspects of this disclosure are not limited to the specific processor-executable instructions or specific components or modules shown in the accompanying drawings and described herein. Other embodiments may include different processor-executable instructions or components having more or fewer functions than those shown and described herein.

[0065] Unless otherwise stated, the order of execution or performance of the operations according to various aspects of this disclosure shown and described herein is not essential. That is, unless otherwise stated, operations may be performed in any order, and embodiments may include more or fewer operations than those disclosed herein. For example, it is contemplated that a particular operation may be performed before, simultaneously with, or after another operation within the scope of this invention.

[0066] When describing elements of the invention or embodiments thereof, the articles “a,” “an,” “the,” and “the” are intended to indicate the presence of one or more elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that additional elements may be present in addition to those listed.

[0067] Not all components depicted in the illustrations or descriptions are essential. Furthermore, some implementations and embodiments may include additional components. Variations in the arrangement and type of components may be made without departing from the spirit or scope of the claims set forth herein. Additional, different, or fewer components may be provided, and components may be combined. Alternatively or additionally, a component may be implemented from several components.

[0068] The above description illustrates embodiments by way of example and not limitation. This description enables those skilled in the art to make and use aspects of the invention, and describes numerous embodiments, adaptations, variations, alternatives, and uses of aspects of the invention, including modes currently considered best for carrying out aspects of the invention. Furthermore, it should be understood that aspects of the invention are not limited in their application to the details of the construction and arrangement of components set forth in the following description or shown in the accompanying drawings. Aspects of the invention can have other embodiments and can be practiced or performed in various ways. Moreover, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered limiting.

[0069] It is obvious that modifications and variations are possible without departing from the scope of the invention as defined in the appended claims. Since various changes can be made to the above structures and methods without departing from the scope of the invention, all content contained in the above description and shown in the drawings is intended to be illustrative rather than restrictive.

[0070] In view of the foregoing, it will be seen that several advantages of realizing various aspects of the present invention have been achieved and other advantageous results have been obtained.

[0071] The abstract and summary are provided to help readers quickly determine the nature of this technical disclosure. They are submitted with the understanding that they are not intended to interpret or limit the scope or meaning of the claims. The summary is provided to introduce some concepts in a simplified form, which will be further described in the detailed embodiments. The summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help identify the claimed subject matter.

Claims

1. A current transformer, comprising: a core having a passage therethrough, the passage configured to receive one or more conductors; a housing sized and shaped to receive the core, the housing having a plurality of grooves formed in an outer surface thereof, the grooves spaced according to a predetermined winding distribution pattern; a sense winding wrapped around the core and the housing, the sense winding configured to magnetically couple to a conductor passing through the core passage, the sense winding further configured to generate a fault signal in response to a ground fault condition in the conductor, wherein the sense winding is wrapped around the core and the housing such that portions of the sense winding are positioned in select grooves of the housing according to the predetermined winding distribution pattern.

2. The current transformer of claim 1, further comprising a test winding wrapped around the core and the housing, the test winding configured to generate a test signal in response to a test signal excitation applied thereto, such that the test signal magnetically couples to the sense winding, wherein the test winding is wrapped around the core and the housing such that portions of the test winding are positioned in other select grooves of the housing according to the predetermined winding distribution pattern.

3. The current transformer of claim 1, further comprising an enclosure housing the core, the housing, and the windings.

4. The current transformer of claim 3, wherein the enclosure comprises two pieces engaged with one another in a snap-fit relationship.

5. The current transformer of claim 3, wherein, the enclosure includes a pin sized and shaped to fit in the core passage, the pin configured to receive the conductor and hold the received conductor in a predetermined position within the core passage.

6. The current transformer of claim 5, wherein, the pin is Y-shaped and configured to receive three conductors.

7. The current transformer of claim 3, wherein, the housing includes a first locking feature and the enclosure includes a second locking feature, the first and second locking features engaged with one another in a mating relationship to prevent rotation of the housing and the core relative to the enclosure.

8. The current transformer of claim 7, wherein the first locking feature of the housing includes a protrusion and the second locking feature of the enclosure includes a slot sized and shaped to receive the protrusion.

9. The current transformer of claim 1, wherein the housing is configured for use with an industrial winding machine.

10. An assembly guide for a current transformer, the assembly guide comprising: a housing sized and shaped to receive a core of a current transformer; and a plurality of grooves formed in an outer surface of the housing, the grooves spaced according to a predetermined winding distribution pattern such that portions of a sense winding wrapped around the core and the housing are positioned in select grooves of the housing according to the predetermined winding distribution pattern.

11. The assembly guide of claim 10, wherein, the grooves of the housing are spaced according to the predetermined winding distribution pattern such that portions of a test winding wrapped around the core and the housing are positioned in other select grooves of the housing according to the predetermined winding distribution pattern.

12. The assembly guide of claim 10, further comprising an outer shell housing the core, the housing, and the winding.

13. The assembly guide of claim 12, wherein, The outer shell comprises two pieces that engage one another in a snap-fit relationship.

14. The assembly guide of claim 12, wherein, The core has a channel therethrough configured to receive one or more conductors, and wherein the housing comprises a pin sized and shaped to fit in the core channel, the pin configured to receive the conductors and hold the received conductors in a predetermined position within the core channel.

15. The assembly guide of claim 14, wherein, The pin is Y-shaped and configured to receive three conductors.

16. The assembly guide of claim 12, wherein, The housing comprises a first locking feature and the outer shell comprises a second locking feature, the first and second locking features engaging one another in a mating relationship to prevent rotation of the housing and the core relative to the outer shell.

17. The assembly guide of claim 16, wherein, The first locking feature of the housing comprises a protrusion and the second locking feature of the outer shell comprises a slot sized and shaped to receive the protrusion.

18. An assembly guide for a current transformer, the assembly guide comprising: an outer shell configured to house a core and a winding of a current transformer, the core having a channel therethrough configured to receive one or more conductors; a pin extending along a central axis of the outer shell, the pin sized and shaped to fit in the core channel, the pin configured to receive the conductors and hold the received conductors in a predetermined position within the core channel.

19. The assembly guide of claim 18, wherein, The outer shell comprises two pieces that engage one another in a snap-fit relationship.

20. The assembly guide of claim 18, wherein, The pin is Y-shaped and configured to receive three conductors.

21. The assembly guide of claim 18, further comprising a housing sized and shaped to receive the core of the current transformer, the housing having a plurality of grooves formed in an outer surface thereof, the grooves spaced apart according to a predetermined winding distribution pattern such that portions of a sense winding wound about the core and the housing are positioned in select grooves of the housing according to the predetermined winding distribution pattern.

22. The assembly guide of claim 21, wherein, The grooves of the housing are spaced apart according to the predetermined winding distribution pattern such that portions of a test winding wound about the core and the housing are positioned in other select grooves of the housing according to the predetermined winding distribution pattern.

23. The assembly guide of claim 21, wherein, The housing comprises a first locking feature and the outer shell comprises a second locking feature, the first and second locking features engaging one another in a mating relationship to prevent rotation of the housing and the core relative to the outer shell.

24. The assembly guide of claim 23, wherein, The first locking feature of the housing comprises a protrusion and the second locking feature of the outer shell comprises a slot sized and shaped to receive the protrusion.

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