Portable voltage detector and system for warning of voltage hazards

Abstract

A portable voltage detector (100) comprises a housing (106), a sensor circuit accommodated in the housing (106) for sensing electrical fields (501) within a detection range of the portable voltage detector (100) and an evaluation unit accommodated in the housing (106) for evaluating the sensed electrical fields, the evaluation unit being connected to the sensor circuit. A warning device (104) connected to the evaluation unit is configured to output a warning signal if the strength of an electrical field (501) sensed by the sensor circuit reaches or exceeds a warning threshold. A wireless communication interface of the portable voltage detector (100), which wireless interface is connected to the evaluation unit, is designed to receive a setting signal in order to define the warning threshold. A voltage source connected to the sensor circuit and to the communication interface is designed to be charged by means of an inductive charging unit.

Description

[0001] Portable voltage detector and voltage hazard warning system

[0002] The invention relates to a portable voltage detector for detecting electric fields near live electrical lines and a system for warning of voltage hazards.

[0003] Portable voltage detectors are designed to warn users of approaching live electrical lines, allowing them to avoid contact with the lines or maintain a safe distance. In the field of technical work on electrical lines and systems, portable voltage detectors thus provide an additional option for increasing work safety.

[0004] The functionality of such voltage detectors is based on the fact that the electric field of a live wire generates an electrical displacement current in a sensor element of the voltage detector, which can be measured and evaluated. If it is determined that a predefined warning threshold is exceeded, the voltage detector can warn the user, for example, with an acoustic warning.

[0005] The decisive factor for the successful use of portable voltage detectors is therefore the defined warning threshold, i.e. how sensitive the voltage detector is set.

[0006] A lower warning threshold ensures that the voltage detector will trigger, even at greater distances from the live line, if the voltage remains constant. While this provides a high level of safety, it can cause the portable voltage detector to trigger excessively frequently when working with or near medium- and high-voltage lines. "High voltage" is defined here and below as a voltage of at least 1 kV AC, whereas "low voltage" is defined as a voltage below 1 kV AC.

[0007] The “high voltage” range is also usually divided into areas, namely the medium voltage range (up to 60 kV), the high voltage range (from 60 kV to 220 kV) and the extra high voltage range (from 220 kV).

[0008] If, however, a higher warning threshold is used, the user is given greater responsibility, since if the voltage remains constant, the portable voltage detector will only issue a warning at a significantly shorter distance to the live line.

[0009] In the case of laypersons or persons with only electrical training, a complete assessment of the danger posed by live wires cannot be assumed. Therefore, a portable voltage detector for this user group must be as sensitive as possible. Furthermore, the voltage detector should be as easy to operate as possible to prevent misuse. Examples of persons in such a user group include members of public emergency services such as firefighters, paramedics, police, and technical emergency services, as well as construction workers and installers in the gas, water, and / or sewage disposal sectors.

[0010] Electrically skilled workers, on the other hand, can be assumed, due to their training, to have a heightened awareness and sufficient ability to assess the danger posed by live electrical lines. For this user group, the portable voltage detector serves merely as an additional warning device. However, this presents the challenge that when working on complex electrical cable systems, only individual branches may be de-energized, requiring work to be carried out at a relatively short distance from live electrical lines. To prevent the portable voltage detector from constantly triggering, these users must be able to adjust the warning threshold on-site and depending on the situation.Until now, it has been common practice to provide different voltage detectors for these different requirement profiles, which, however, results in high procurement, storage and maintenance costs.

[0011] Another challenge in the design of portable voltage detectors is their power supply. This is typically provided by built-in primary or secondary cells. Primary cells can only be used once and are not desirable for environmental reasons. Secondary cells can be recharged. For this purpose, a charging port, such as a mini- or micro-USB interface, is commonly provided in the voltage detector's housing.

[0012] The disadvantage of this solution is that an opening must be created in the voltage detector's housing, allowing dirt and moisture to penetrate. This disadvantage is further compounded by the fact that work on live wires, especially in the case of high-voltage systems, often has to be carried out in harsh environments and inclement weather conditions. In this case, additional sealing of the charging port is required, which significantly increases the design effort. Furthermore, it is inconvenient for the user to have to connect charging cables while wearing the protective gloves required for the work.

[0013] The object of the invention is to provide a portable voltage detector that is suitable for a wide range of user groups, is easy to handle and can reliably warn of live electrical lines.

[0014] The object is achieved according to the invention by a portable voltage detector comprising a housing, a sensor circuit accommodated in the housing for detecting electric fields within a detection range of the portable voltage detector, and an evaluation unit accommodated in the housing for evaluating the detected electric fields. The evaluation unit is connected to the sensor circuit. Furthermore, the evaluation unit is connected to a warning device configured to emit a warning signal if the strength of an electric field detected by the sensor circuit reaches or exceeds a warning threshold.In addition, the portable voltage detector comprises a wireless communication interface connected to the evaluation unit, which is designed to receive a setting signal in order to set the warning threshold, and a voltage source connected to the sensor circuit and the communication interface, which is designed to be charged by means of an inductive charging unit.

[0015] The portable voltage detector according to the invention enables flexible adjustment of the respective warning threshold via the setting signal. This makes it possible to use the same portable voltage detector for different work environments and user groups. In other words, it is no longer necessary to purchase and maintain multiple voltage detectors for different purposes, which can significantly reduce the costs involved.

[0016] The wireless communication interface can be operated using all common connection methods for wireless data transmission.

[0017] Preferably, the communication speed is configured to use a Bluetooth Low Energy connection for data exchange to further reduce the power consumption of the portable voltage detector. This also further increases the reliability of the portable voltage detector, as the risk of insufficient power supply and thus unplanned failure is reduced.

[0018] The evaluation unit is designed in particular on a processor.

[0019] Furthermore, according to the invention, the housing of the portable voltage detector does not require an opening through which a charging socket for charging the voltage source or replacing the voltage source would be connected. Instead, the portable voltage detector can be charged by simply placing it on an inductive charging surface to initiate the charging process. Such inductive charging surfaces are becoming increasingly popular and are available worldwide.

[0020] In other words, the voltage source is inductively chargeable. For example, the user's emergency vehicle may have an inductive charging surface, allowing the portable voltage detector to be charged while traveling to or from the intended site and / or between different sites.

[0021] The inductive charging process can be carried out according to all common inductive charging standards, for example, using the Qi standard of the Wireless Power Consortium or the AirFuel standard of the AirFuel Alliance. Preferably, the power source is configured for inductive charging using the Qi standard.

[0022] In particular, the housing is made of plastic, so the overall weight and cost of the portable voltage detector are low.

[0023] Since recharging the voltage source is easy and uncomplicated, the total capacity of the voltage source can be designed to be comparatively small.

[0024] For example, the voltage source has a capacity in the range of 100 to 200 mAh. This allows the voltage source to be designed as compact and lightweight as possible, thus also reducing the overall size and weight of the voltage detector.

[0025] The warning signal emitted by the warning device may be a visual warning signal, an acoustic warning signal and / or a vibration signal.

[0026] For example, the warning device comprises a lamp, in particular an LED, and / or a piezo buzzer.

[0027] In one embodiment, the warning device has a vibration motor for generating the vibration signal. In other words, the vibration signal emitted by the warning device can be a haptic signal.

[0028] Preferably, the warning device is configured to emit a visual warning signal, an acoustic warning signal, and a haptic signal if the strength of an electric field detected by the sensor circuit reaches or exceeds a warning threshold. To further reduce the complexity of the portable voltage detector, the portable voltage detector may comprise only a single manual control element, wherein the single manual control element is configured to adjust the evaluation unit. In particular, the single manual control element is configured to adjust the warning threshold and / or control an output of the evaluation unit.

[0029] For example, the individual manual control can be configured to deactivate a warning signal currently emitted by the portable voltage detector when activated. In other words, this allows the user to confirm that the warning signal has been perceived.

[0030] In one variant, the individual manual control element is configured to control whether the evaluation unit sends a control signal to the warning device when triggered. Thus, the user can use the individual manual control element to determine whether or not a warning signal is currently being issued.

[0031] If the warning device comprises several components, for example a visual indicator and an acoustic indicator, the single manual control element can be designed to set which of the components are activated when the warning threshold is exceeded, for example only an LED or only a piezo buzzer.

[0032] The individual manual control element can also be configured to adjust or replace the warning threshold stored in the evaluation unit.

[0033] Preferably, the single manual control element is a push button.

[0034] The sensor circuit can comprise a sensor element for detecting electric fields and an amplifier circuit connected in series with the sensor element. The amplifier circuit serves to enable reliable evaluation, even if the measurement signal generated in the sensor element is weak.

[0035] The sensor element is, in particular, a metal foil or a weakly conductive plastic film, for example, a metallically coated plastic film. The amplifier circuit can comprise a voltage divider with a pre-amplification function. In other words, the electric field detected by the sensor element is measured via a measuring resistor consisting of two resistors connected in parallel, with an amplification element, for example, an impedance converter, being provided, in particular, at the midpoint between these two resistors.

[0036] The voltage divider is in particular a high-impedance 1:1 voltage divider.

[0037] In order to generate a rectified signal from the alternating field of the displacement current, which is easily comparable with the warning threshold, the sensor circuit can comprise an operational amplifier circuit with a low-pass filter, which is arranged between the voltage divider and the evaluation unit.

[0038] In one variant, the evaluation unit is embodied by a microcontroller, wherein the microcontroller is particularly configured to switch between a sleep mode ("standby") and an operating mode. The microcontroller can periodically switch between the sleep mode and the operating mode, whereby only in the operating mode does the microcontroller compare a measured value of the sensor element processed by the sensor circuit with the warning threshold and send a control signal to the warning device when the warning threshold is reached or exceeded. Alternatively, the microcontroller can switch from sleep mode to the operating mode if a comparator connected upstream of the microcontroller detects that the warning threshold has been reached, and send a control signal to the warning device in the operating mode.

[0039] In other words, the microcontroller is designed to be in sleep mode as often as possible, reducing its power consumption. This allows the overall power consumption of the voltage detector to be reduced, allowing for a longer operating time without recharging while maintaining the same capacity of the voltage source.

[0040] Optionally, the sensor circuit can include an attenuator connected upstream of the amplifier circuit. Such a design is particularly advantageous if the portable voltage detector is to be used for work near medium- and high-voltage lines, since the particularly high voltages expected there can cause very high displacement currents to occur at the sensor element. In this case, the attenuator ensures that the other components and parts of the sensor circuit and the evaluation unit are not damaged by these very high displacement currents. Furthermore, the measuring range of the sensor circuit is increased by the use of the attenuator.

[0041] The attenuator is, for example, a capacitor connected in parallel to the voltage divider.

[0042] The attenuator can be used in different operating modes.

[0043] For example, the attenuator may have no influence on the measurement signal generated by the sensor element in a first operating mode and attenuate the measurement signal generated by the sensor element in a second operating mode.

[0044] In other words, if the attenuator is intended for use in the vicinity of electrical conductors operating at medium or high voltage, it can be switched to the second operating mode to protect the other components and parts of the voltage detector from excessive electrical loads. However, if only lower displacement currents are expected, for example, when working near low-voltage systems, the attenuator can be switched to the first operating mode to allow the sensor circuit to reliably process the correspondingly smaller measurement signals.

[0045] The operating mode of the attenuator can be adjusted via the microcontroller.

[0046] In a further embodiment, the attenuator can have a third operating mode, wherein in the third operating mode, the attenuator generates a test signal independent of the sensor element, with which the functionality of the sensor circuit can be checked. In other words, the portable voltage detector in this case has a self-test function.

[0047] To enable the user of the voltage detector to check the functionality of the voltage detector himself, the test signal can be triggered via the individual manual control element.

[0048] The object of the invention is further achieved according to the invention by a system for warning of voltage hazards, comprising a portable voltage detector as described above and a mobile device, wherein the mobile device is designed to exchange data with the wireless communication interface of the portable voltage detector.

[0049] The mobile device is, for example, a smartphone or a tablet, which can be carried by the user when the portable voltage detector is in use.

[0050] According to the invention, the portable voltage detector can be controlled via the mobile device, for example by means of an application or other control program available on the mobile device.

[0051] In particular, the warning threshold can be set via the mobile device and transmitted to the evaluation unit via the setting signal.

[0052] In addition, the mobile device may have a human-machine interface (HMI), in particular a touch-sensitive display on which at least one piece of information relating to the operation of the voltage detector can be displayed.

[0053] The information on the operation of the voltage detector includes, for example, the warning threshold, the currently measured strength of the electric field in the detection range of the portable voltage detector, the position of the user, the current time and / or the charge level of the voltage source.

[0054] The mobile device may further have a logging function for storing information on the operation of the voltage detector, in particular a history of the obtained measurement data, time information, location information, and / or actuations of the individual manual control elements. The information on the operation of the voltage detector may be stored locally on the mobile device and / or transmitted to a server via the mobile network, in particular via the communication interface (and optionally via the mobile device).

[0055] The separation of the portable voltage detector and the mobile device for configuring the warning threshold allows the same voltage detector to be used for different user groups.

[0056] For example, the warning threshold is set once using the mobile device, and then the portable voltage detector is passed on to the user, who, apart from the functions of the individual manual control element, cannot influence the operation of the current detector. This variant is particularly advantageous if the user is a layperson or someone with only electrical training, such as an emergency responder.

[0057] Alternatively, the entire system, including the portable voltage detector and mobile device, can be left to the user, allowing the voltage detector's warning threshold to be adjusted and / or information to be read out even while the detector is in use. This option is preferred if the user is an electrical engineer.

[0058] Further features and characteristics of the invention will become apparent from the following detailed description of selected embodiments, which are not intended to be limiting, and from the drawings, in which:

[0059] - Fig. 1 shows a system according to the invention for warning of voltage hazards with a portable voltage detector according to the invention;

[0060] - Fig. 2 is a schematic representation of selected components of the system from Fig. 1;

[0061] - Fig. 3 shows a further schematic representation of selected components of the voltage detector from Fig. 1 and an inductive charging station; - Fig. 4 shows a first embodiment of a sensor circuit of the voltage detector from Fig. 1;

[0062] - Fig. 5 shows a second embodiment of the sensor circuit;

[0063] - Fig. 6 shows a third embodiment of the sensor circuit; and

[0064] - Fig. 7 a fourth embodiment of the sensor circuit.

[0065] Fig. 1 shows a system 200 according to the invention for warning of voltage hazards, for example for warning of an electric field 501 emanating from a high-voltage line 500, i.e. a live line.

[0066] It is understood that instead of the high-voltage line 500, any other current-carrying electrical line may also be meant, in particular a low-voltage, medium-voltage and / or extra-high-voltage line, or another current-carrying component or component to which a voltage is applied.

[0067] The system 200 includes a portable voltage detector 100 and a mobile device 201.

[0068] The portable voltage detector 100 has a single manual control element 101, which in the illustrated embodiment is designed as a push button. The function of the control element 101 will be discussed in more detail later.

[0069] Furthermore, the portable voltage detector 100 comprises a visual warning indicator 102, for example an LED, and an acoustic warning indicator 103, for example a piezo buzzer, which are part of a warning device 104 of the portable voltage detector 100.

[0070] The other components of the portable voltage detector 100 are accommodated in a housing 106, which has no further openings apart from the necessary loudspeaker openings of the acoustic warning indicator 103 and the openings for mounting the individual manual control element 101 and the optical warning indicator 102, so that the portable voltage detector 100 is insensitive to environmental influences such as dirt and / or water.

[0071] In the illustrated embodiment, mobile device 201 is a smartphone. In principle, other mobile devices, such as a tablet, can also be considered as part of the system 200 according to the invention.

[0072] The mobile device 201 has a human-machine interface 202, which is designed as a touch-sensitive display.

[0073] In addition, an app for controlling the portable voltage detector 100 is installed on the mobile device 201.

[0074] Fig. 2 shows selected components of the portable voltage detector 100 and the mobile device 201.

[0075] The portable voltage detector 100 has a sensor element 108 for detecting electric fields in a detection area 109 of the portable voltage detector 100, for example, for detecting the electric field 501 generated by the current flowing through the high-voltage line 500.

[0076] The sensor element 108 is, for example, a metal foil or a slightly electrically conductive plastic foil and has a total area of ​​a few square centimeters, for example a total area of ​​1 to 25 cm 2 , especially from 1 to 16 cm 2 , preferably from 1 to 10 cm 2 .

[0077] The sensor element 108 is connected to an evaluation unit 112 via a sensor circuit 110.

[0078] In the embodiment shown, the evaluation unit 112 is formed by a microcontroller which evaluates the signal received from the sensor circuit 110.

[0079] The sensor circuit 110 includes an amplifier circuit 114 and an operational amplifier circuit 116.

[0080] A warning threshold is stored in the evaluation unit 112, i.e. in the microcontroller, and when this threshold is exceeded, the evaluation unit 112 sends a control signal to a triggering unit 118 of the warning device 104, on the basis of which a warning signal is output by means of the optical warning display 102 and / or the acoustic warning display 103.

[0081] The individual manual control element 101 is also connected to the evaluation unit 112 via a control unit 120.

[0082] Furthermore, the voltage detector 100 has a wireless communication interface 122 by means of which a setting signal can be received that defines the warning threshold.

[0083] The components of the voltage detector 100 are supplied with electrical energy by a voltage source 124. The voltage source 124 is permanently installed within the housing 106 and is a secondary battery with a capacity in the range of 100 to 200 mAh.

[0084] The mobile device 201 also has a wireless communication interface 205 so that the portable voltage detector 100 and the mobile device 201 can communicate with each other wirelessly.

[0085] In the embodiment shown, a Bluetooth Low Energy connection 300 is used for this purpose. It is understood that, in principle, any type of wireless communication between the portable voltage detector 100 and the mobile device 201 can be used, as long as reliable data exchange is ensured.

[0086] The mobile device 201 also has a protocol module 206 and a connection module 208 for establishing a mobile data connection.

[0087] The protocol module 206 can store at least one piece of information relating to the operation of the portable voltage detector 100, which the mobile device 201 receives via the wireless communication interface 205, in particular a history of the measurement data obtained in the portable voltage detector 100, time information, location information and / or actuations of the individual manual control element 101.

[0088] The information stored in the protocol module 206 regarding the operation of the portable voltage detector 100 can be used to analyze the accident after an accident in order to clarify the causes of the accident and, based on the results of this analysis, to take measures to further increase occupational safety in the future.

[0089] At least some of the information relating to the operation of the portable voltage detector 100 can be displayed on the human-machine interface 202 via a display module 210.

[0090] User inputs made via the human-machine interface 202 can be evaluated via a configuration module 212.

[0091] Any information stored in the protocol module 206 can be transmitted to a server via a mobile data connection via the connection module 208.

[0092] Additionally, an acoustic output means 214 is provided. In addition to the components of the warning device 104 of the portable voltage detector 100, a warning signal can be emitted via the acoustic output means 214 if the microprocessor of the portable voltage detector 100 detects that the warning threshold has been exceeded.

[0093] The mobile device 201 can be configured to trigger a vibration alarm if the evaluation unit 112 of the portable voltage detector 100 detects that the warning threshold has been exceeded, as indicated by the dashed lines 204 in Fig. 1.

[0094] The various components and modules of the mobile device 201 are connected to a processor 209, which is configured to control the functions of the individual components and modules of the mobile device 201.

[0095] The system 200 according to the invention is characterized in that the portable voltage detector 100 can be used either together with the mobile device 201 or individually.

[0096] In particular, when the system 200 according to the invention is used by trained personnel as an additional means to increase occupational safety, the portable voltage detector 100 is used together with the mobile device 201. In this way, the on-site personnel can adjust the warning threshold to suit the situation as needed, for example, to avoid unnecessary false alarms due to an excessively low warning threshold.

[0097] However, if the portable voltage detector 100 is used by untrained personnel, for example, laypersons or persons with only electrical training, such as emergency personnel, the warning threshold can be set centrally using the mobile device 201, and the portable voltage detector 100 can be used individually. In this case, the user has no way of independently adjusting the warning threshold and thus also no way of setting the warning threshold too low due to an incorrect hazard assessment.

[0098] The system 200 according to the invention is thus suitable for different user groups without having to maintain different types of portable voltage detectors 100.

[0099] Fig. 3 shows a further schematic representation of the portable voltage detector 100 in conjunction with an inductive charging unit 400.

[0100] The inductive charging unit 400 is supplied with electrical energy via a power supply 402 and has a transmitter module 404 and a transmitter coil 406.

[0101] The inductive charging unit 400 is controlled by a processor 408, which is connected to the power supply 402 and the transmitter module 404.

[0102] The portable voltage detector 100 has a receiving coil 125 and a receiving module 126 with charging control.

[0103] A wireless charging connection 600 can be established between the portable voltage detector 100 and the inductive charging unit 400 between the transmitter coil 406 and the receiver coil 125, in particular a wireless charging connection according to the Qi standard.

[0104] The receiving module 126 is connected to the voltage source 124 and to a monitoring module 128 for monitoring the charge state of the voltage source 124. The evaluation unit 112 is also connected to the monitoring module 128.

[0105] Charging the portable voltage detector 100 using wireless charging technology eliminates the need for an additional opening in the housing 106 for a charging interface. This increases resistance to environmental influences such as moisture and / or dirt. Furthermore, handling of the portable voltage detector 100 is made easier.

[0106] Fig. 4 shows a circuit diagram of a first embodiment of the sensor circuit 110.

[0107] In this embodiment, the amplifier circuit 114 is formed by a voltage divider 130 with an amplifier circuit 132.

[0108] The voltage divider 130 is a high-resistance 1:1 voltage divider using resistors connected in parallel, designated R4 and R13 in Fig. 4, which have, for example, a resistance of 2.0 MΩ or more.

[0109] The voltage divider 130 therefore measures the current determined by the sensor element 108 as a measurement signal. The measurement signal determined by the sensor element 108 also has a voltage V| N on.

[0110] Between voltage divider 130 and sensor element 108, an upstream capacitor 134 is provided, via whose capacitance an attenuation factor of the measurement signal of the sensor element 108 can be determined.

[0111] The measurement signal represents a bipolar signal due to the detection of the change in the electric field 501 in the detection area 109. The sensor circuit 110 serves, among other things, to convert the output signal of the sensor circuit 110 into a unipolar signal in order to simplify the comparison of this unipolar signal with the warning threshold.

[0112] The voltage V| N is pre-amplified to a voltage VAMP by an impedance converter 136 of the amplifier circuit 132 connected to the midpoint of the voltage divider 130. In principle, this signal could already be used by an analog-to-digital converter (ADC) of the evaluation unit 112, i.e., the microcontroller, for comparison with the warning threshold stored in the evaluation unit 112.

[0113] In particular, a post-amplification is also provided, which in this case comprises the resistors R10, R11 and R12, via which the signal fed back into the impedance converter 136 is amplified, which is based on the output signal of the impedance converter 136.

[0114] However, in the embodiment shown in Fig. 4, the operational amplifier circuit 116 is additionally provided, which functions as a rectifier.

[0115] In this, the output signal of the amplifier circuit 114 is rectified via diodes 138 and 140 (voltage VRECT), amplified by means of a second impedance converter 142 and filtered via a low-pass filter 144 (“RC element”) to an output signal with voltage VRMS.

[0116] The embodiment of the sensor circuit 110 shown in Fig. 4 generates an output signal that is transmitted to the ADC of the evaluation unit 112, i.e., the microcontroller. The output signal is inverted relative to the measurement signal generated by the sensor element 108 and has a voltage in the range between half the supply voltage Vcc and ground.

[0117] The limitation to half the supply voltage enables a doubling of the resolution in the ADC of the evaluation unit 112 compared to an amplified measurement signal with voltage VAMP tapped directly after the impedance converter 136.

[0118] In addition, electrical defects in the sensor circuit 110 can be inferred if, in the idle state of the sensor circuit 110, i.e. when there is no electric field 501 in the detection area 109, the voltage is half the supply voltage V Cc. In this way, malfunctions of the sensor circuit 110 can be reliably detected.

[0119] Overall, the sensor circuit 110 is characterized by analog, i.e., hardware-based, effective value generation. In other words, the measurement signal emitted by the sensor element 108 is already processed by the components of the sensor circuit 110 before being transmitted to the evaluation unit 112. In this way, the necessary activity of the evaluation unit 112 can be limited to a minimum, resulting in lower energy consumption and thus a longer service life and increased reliability of the portable voltage detector 100.

[0120] Fig. 5 shows a second embodiment of the sensor circuit 110.

[0121] The second embodiment is essentially the same as the first embodiment, so only the differences will be discussed below. The same reference numerals are used for the same components, and reference is made to the above explanations.

[0122] In the second embodiment, a third diode 146 is provided, whose conduction direction is opposite to that of diode 140 and is used to rectify the output signal of amplifier circuit 114. This compensates for the voltage drop across diode 140 and thus improves the sensitivity of amplifier circuit 114.

[0123] A third embodiment of the sensor circuit 110 is shown in Fig. 6.

[0124] The third embodiment is essentially the same as the first embodiment, so only the differences will be discussed below. The same reference numerals are used for the same components, and reference is made to the above explanations.

[0125] In the third embodiment, an additional attenuator 148 is connected in front of the voltage divider 130 and the amplifier circuit 114.

[0126] The attenuator 148 is connected to an I / O pin of the microcontroller, designated GPIO in Fig. 6, and includes a capacitor that can be adjusted via a signal from the evaluation unit 112. In other words, the attenuator 148 has several operating modes.

[0127] In a first operating mode, the attenuator 148 has no influence on the measurement signal supplied by the sensor element 108. This can be achieved by switching the I / O pin of the evaluation unit 112 to a high impedance, thus preventing the current flow through the capacitor of the attenuator 148. In a second operating mode, the attenuator 148 attenuates the measurement signal supplied by the sensor element 108 by reducing the resistance at the I / O pin of the evaluation unit 112, i.e., the microcontroller, to a desired level. Thus, a portion of the displacement current detected by the sensor element 108 flows through the attenuator 148 and not through the voltage divider 130.

[0128] The attenuator 148 can thus serve as a protective component for the other parts and components of the sensor circuit 110 by avoiding displacement currents that are above the currents that the other parts and components can handle.

[0129] Alternatively or additionally, the attenuator 148 serves to increase the measuring range of the sensor circuit 110.

[0130] For this purpose, the attenuator 148 can also comprise several capacitors connected in parallel, each of which can be controlled via an I / O pin of the evaluation unit 112 in order to be able to realize a tailor-made attenuation effect.

[0131] In a third operating mode, the attenuator 148 generates a test signal independent of the sensor element 108, with which the functionality of the sensor circuit 110 can be checked.

[0132] In this operating mode, a periodically recurring pulsed current signal originating from the evaluation unit 112 is fed into the attenuator 148 via the I / O pin. This generates an alternating current signal that is detected by the voltage divider 130 and amplified, rectified, and filtered via the amplifier circuit 114 and the operational amplifier circuit 116.

[0133] The output signal generated by sensor circuit 110 in this case can be checked and evaluated in evaluation unit 112 by comparing it with an expected measurement signal profile. Thus, in this embodiment, portable voltage detector 100 has a self-test functionality without the need to install additional parts or components. If a deviation from the expected measurement signal profile is detected, evaluation unit 112 is configured to send a control signal to warning device 104 so that it emits a warning signal.

[0134] The self-test can preferably also be started by the user using the single manual control element 101.

[0135] Fig. 7 shows a fourth embodiment of the sensor circuit 110.

[0136] The fourth embodiment is essentially the same as the previous embodiments, so only the differences will be discussed below. The same reference numerals are used for the same components, and reference is made to the above explanations.

[0137] In the fourth embodiment, the voltage divider 130 is connected to the sensor element 108 and the amplifier circuit 114 not at the center point, but at an end connection point.

[0138] Instead, a test circuit 150 is connected to the center point of the voltage divider 130, via which a test signal from a test microcontroller 152 can be fed into the circuit arrangement 110.

[0139] The resistor R300 and the capacitors C300, C301 and C304 shown in Fig. 7 are used to filter and level adjust the test signal fed in by the test microcontroller 152.

[0140] In the fourth embodiment, the amplifier circuit 114 has a three-stage level adjustment with a first control stage 154, a second control stage 156 and a third control stage 158.

[0141] The first control stage 154 represents a permanently installed feedback branch and comprises two resistors R301 and R302 as well as two capacitors 0302 and 0305, each connected in parallel to the resistors R301 and R302, which are also connected in parallel to each other.

[0142] The second control stage 156 comprises an integrated circuit 160, two resistors R313 and R314 and a capacitor C312 connected in parallel with the resistors R313 and R314. The third control stage 158 is constructed analogously to the second control stage 158 and comprises an integrated circuit 162, two resistors R315 and R316 and a capacitor C313 connected in parallel with the resistors R315 and R316.

[0143] Depending on the desired amplification by the amplifier circuit 114, the first control stage 154, the second control stage 156 or the third control stage 158 becomes active in order to achieve the largest possible dynamic range of the sensor circuit 110.

[0144] If the first control stage 154 is active, the gain by the amplifier circuit 114 is at its highest. If the second control stage 156 is activated by means of the integrated circuit 160, the gain by the

[0145] amplifier circuit 114. If the third control stage 158 is activated by means of the integrated circuit 162, the gain is

[0146] Amplifier circuit 114 is attenuated even further than is the case in the second control stage 156.

[0147] In particular, the gain of the amplifier circuit 114 is attenuated by a factor of up to 5 compared to the gain in the first control stage 154 when the second control stage 156 is active.

[0148] If the third control stage 158 is active, the gain of the amplifier circuit 114 is attenuated in particular by a factor of up to 15 compared to the gain in the first control stage 154.

[0149] The output signal of the amplifier circuit 114 is DC-decoupled by means of a capacitor C303 and fed to the operational amplifier circuit 116, which also acts as a rectifier by means of the diodes 138 and 140.

[0150] The operational amplifier circuit 116 comprises an inverting amplifier whose positive output is fixed to the positive reference potential V C c is connected.

[0151] Diodes 138 and 140 are designed such that diode 138 is conductive for positive half-waves of the input signal reaching operational amplifier circuit 116, while diode 140 is conductive for negative half-waves of the input signal. Thus, the amplification factor of operational amplifier circuit 116 is determined by the selection of resistors R304 and R305.

[0152] After filtering via the low-pass filters 144 connected downstream of the operational amplifier circuit 116, a quasi-DC potential is generated, which is fed to the analog-to-digital converter (ADO) of the evaluation unit 112 and is used for comparison with the warning threshold stored in the evaluation unit 112.

[0153] Overall, the system 200 according to the invention is characterized by its flexible use for various user groups, while simultaneously providing reliable detection of electric fields. The portable voltage detector 100 is also particularly robust and equipped with a long-lasting power supply.

Claims

Patent claims 1. Portable voltage detector comprising a housing (106), a sensor circuit (110) enclosed in the housing (106) for detecting electric fields (501) within a detection range (109) of the portable voltage detector (100), an evaluation unit (112) enclosed in the housing (106) for evaluating the detected electric fields, wherein the evaluation unit (112) is connected to the sensor circuit (110), a warning device (104) connected to the evaluation unit (112) which is configured to output a warning signal if the strength of an electric field (501) detected by the sensor circuit (110) reaches or exceeds a warning threshold, a wireless communication interface (122) connected to the evaluation unit (112) which is configured to receive a setting signal to determine the warning threshold, and a voltage source connected to the sensor circuit (110) and the communication interface (122). (124)wherein the voltage source (124) is designed to be charged by means of a unit (400) for inductive charging.

2. Portable voltage detector according to claim 1, wherein the portable voltage detector (100) has only a single manual control element (101), wherein the single manual control element (101) is configured to set the evaluation unit (112), in particular to set the warning threshold and / or to control an output of the evaluation unit (112).

3. Portable voltage detector according to claim 1 or 2, wherein the sensor circuit (110) comprises a sensor element (108) for detecting electric fields (501) and an amplifier circuit (114) connected in series with the sensor element (108).

4. Portable voltage detector according to claim 3, wherein the amplifier circuit (114) comprises a voltage divider (130) with pre-amplification function.

5. Portable voltage detector according to claim 4, wherein the sensor circuit (110) comprises an operational amplifier circuit (116) with a low-pass filter (144) arranged between the voltage divider (130) and the evaluation unit (112).

6. Portable voltage detector according to one of the preceding claims, wherein the evaluation unit (112) is formed by a microcontroller, and wherein the microcontroller is in particular configured to switch between a sleep mode and an operation mode, wherein the microcontroller either periodically switches between the sleep mode and the operation mode and only in the operation mode compares a measured value of the sensor element (108) processed by the sensor circuit (110) with the warning threshold and, if the warning threshold is reached or exceeded, sends a control signal to the warning device (104), or the microcontroller switches from sleep mode to operation mode if a comparator upstream of the microcontroller detects that the warning threshold has been reached and, in the operation mode, sends a control signal to the warning device (104).

7. Portable voltage detector according to one of claims 3 to 6, wherein the sensor circuit (110) comprises an attenuator (148) which is connected upstream of the amplifier circuit (132).

8. Portable voltage detector according to claim 7, wherein the attenuator (148) has no effect on the measurement signal generated by the sensor element (108) in a first operating mode and attenuates the measurement signal generated by the sensor element (108) in a second operating mode.

9. Portable voltage detector according to claim 7 or 8, wherein the attenuator (108) in a third operating mode generates a test signal independent of the sensor element (108), with which the functionality of the sensor circuit (110) can be verified.

10. System for warning of voltage hazards, comprising a portable Voltage detector (100) according to one of the preceding claims and a mobile device (201), wherein the mobile device (201) is configured for data exchange with the wireless communication interface (122) of the portable voltage detector (100).

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