Abstract: A method for generating an error signal that characterizes a ground fault on a conductor between two conductor ends. A differential value is formed and the error signal is generated when the differential value meets a prescribed initiating condition. A first comparison value is determined for a selectable location on the conductor using at least one measured current and voltage value taken at a prescribed measurement point in time at one end of the conductor. The comparison value indicates the current or the voltage that should flow or be present at the selectable location in an error-free state. A second comparison value is determined for the selectable location on the conductor using at least one measured current or voltage value, taken at the prescribed measurement point in time at the other end of the conductor. The two comparison values are subjected to difference formation, forming the differential value.

Abstract: A multi-scanner device having a detection unit and an outlet tester that can be selectively connected together for convenient use and easy storage. Preferably, a plug on the outlet tester is inserted into a non-functional socket located on the detection unit to form a multi-scanner device with a detachable outlet tester.

Abstract: A magnetic flowmeter is disclosed that includes a pair of electrodes coupled to a process fluid and a diagnostic circuit coupled to the pair of electrodes to monitor a common mode signal. The diagnostic circuit is adapted to detect a poor ground connection associated with at least one electrode of the pair of electrodes based on line noise associated with the common mode signal.

Abstract: A method and circuit for determining a circuit element parameter in a ground fault circuit interrupter circuit. An electrical signal provided to a first node is used to generate another electrical signal at a second node. The electrical signal at the second node is multiplexed with a modulation signal to generate a modulated signal that is then filtered and converted into a digital representation of a portion of the circuit element parameter. The electrical signal at the second node is multiplexed with the modulation signal after it has been phase shifted to produce a modulated signal that is filter and converted into a digital representation of another portion of the circuit element parameter. In another aspect, a slope based solenoid self-test method is used for self-testing in a GFCI circuit. Alternatively, a method for determining a wiring fault is provided using a digital filter.

Abstract: Various systems, methods and apparatus are described for detecting an excessive or faulty ground current in a conductive wire or electronic device. A ground current detector is coupled to a known earth ground to determine whether other ground lines are carrying excessive, faulty and/or leaking currents. If these types of unsafe conditions are detected, then a user can take appropriate action to locate and correct these problems.

Abstract: A device and method to determine the presence of a ground fault that distinguishes between the capacitive portion of the currents to ground, and the resistive portion of the currents to ground by ascertaining aspects of the voltage and residual current waveforms.

Abstract: In a construction machine in which a motor is driven by battery power through an inverter in accordance with operation of an operating lever, current-leakage detection signal output means applies a voltage signal, which is adapted for detection of a current leakage, between DC buses connected to the battery and a body of the machine. The applied signal voltage is detected by signal detection means, and the occurrence or non-occurrence of a current leakage is determined based on a crest value of the detected voltage signal. When the operating lever is operated during the determination, the determination is suspended to prevent erroneous detection.

Abstract: A ground fault detection device includes a sense coil including a primary winding and a secondary winding to detect current in a line conductor and a neutral conductor.

Abstract: A ground fault detection system detects an earth fault or ground fault in a network device. The network device may be used in a fire alarm network. The ground fault detection system includes a power device that electrically isolates the ground fault detection system. A controller sequences a series of switches or relays to charge an energy storing element, such as a capacitor, with the isolated power supply. The capacitor is placed in communication with each port of the network device one at a time. If the connected port includes an inadvertent connection to ground, a detection circuit will detect the bias on the earth ground. The detection circuit may then output an indication of the inadvertent connection to ground to either a workstation or a fire alarm control panel.

Abstract: An insulation state detector detects an insulation state with respect to a ground potential portion of a DC power source on the basis of a charging voltage of a flying capacitor. The insulation state connector includes a detecting section that detects the insulation state of the DC power source by defining the charging voltage of the flying capacitor in the ground fault state as a charging voltage, in an unbalanced state where voltages across both ends of the positive-side Y capacitor and the negative-side Y capacitor are not equal to voltages obtained by dividing the voltage of the DC power source according to a voltage division ratio of the positive-side ground fault resistor and the negative-side ground fault resistor.

Abstract: The present invention relates to an electrical leak detecting apparatus for an electric vehicle, which is capable of not only detecting an electrical leak generated when a vehicle body is connected to the maximum potential or minimum potential of a battery pack, but also detecting which portion of the battery pack the vehicle body is connected to when an electrical leak is generated through the connection of the vehicle body and an intermediate potential of the battery pack.

Abstract: A method detects a short circuit in a load current path that includes an inductive load.

Abstract: Various systems, methods and apparatus are described for detecting an excessive or faulty ground current in a conductive wire or electronic device. A ground current detector is coupled to a known earth ground to determine whether other ground lines are carrying excessive, faulty and/or leaking currents. If these types of unsafe conditions are detected, then a user can take appropriate action to locate and correct these problems.

Abstract: A power supply controller includes a semiconductor switching element disposed on a current supply line from a power source to a load. The semiconductor switching element is switched between ON and OFF for controlling power supply to the load. A short anomaly of the semiconductor switching element is determined if at least one of an input-to-output voltage of the semiconductor switching element being smaller than a first threshold and the semiconductor switching element being in an ON state is detected, when an OFF signal for instruction to turn OFF the semiconductor switching element is received.

Abstract: The present invention is directed to an electrical wiring device that includes an automatic self-test assembly coupled to the plurality of line terminals or the plurality of load terminals, the detection circuit, the fault detection circuit and the circuit interrupter assembly. The automatic self-test assembly is configured to cause the detection circuit to generate a simulated sensor fault signal during a predetermined half-cycle of an AC line cycle in accordance with a predetermined periodic testing schedule, monitor the fault detection signal corresponding to the simulated sensor fault signal, and generate a test result signal based on monitoring the fault detection signal. The automatic self-test assembly also includes a noise immunized decision circuit configured to evaluate a plurality of test results to thereby provide a noise immunized end-of-life signal.

Abstract: In a first aspect, a device is provided for use with an AC power system that includes a line conductor, a neutral conductor and a transformer, the line conductor and the neutral conductor are each coupled between a source and a load, the neutral conductor is coupled to ground at the source, and the transformer includes a first primary winding coupled in series with the line conductor, a second primary winding coupled in series with the neutral conductor, and a secondary winding. The device includes a first circuit coupled to the secondary winding, wherein the first circuit provides a first detection signal if a current from the line conductor to ground exceeds a first predetermined threshold. The device also includes a second circuit coupled to the secondary winding, wherein the second circuit includes an AC signal source that provides an AC signal at a specified amplitude and a specified frequency to the secondary winding.

Abstract: A ground fault detection device includes a sense coil including a primary winding and a secondary winding to detect current in a line conductor and a neutral conductor. It also includes a capacitor in parallel with the secondary winding and a virtual inductor to form a resonance circuit having a signal proportional to the current and being indicative of a ground fault condition.

Abstract: Methods to test the operation of the pick-up coil without having to de-energize the power line serving as the power line carrier in order to perform testing on the pick-up coil. A sweep wave is introduced and parameters of the pick-up coil can be measured to detect the presence or absence of resonant behavior indicative of the health of the pick-up coil. Testing capabilities may be incorporated into a power line carrier receiver and use the connections between the pick-up coils and the receiver to perform the pick-up coil test. Several methods for evaluating the pick-up coil response to a series of test inputs of different frequencies are presented. These methods could be incorporated in a pick-up coil testing device that is independent of a receiver.

Abstract: Methods to test the operation of the pick-up coil without having to de-energize the power line serving as the power line carrier in order to perform testing on the pick-up coil. A series of at least one test frequency is introduced and parameters of the pick-up coil can be measured to detect the presence or absence of resonant behavior indicative of the health of the pick-up coil. Testing capabilities may be incorporated into a power line carrier receiver and use the connections between the pick-up coils and the receiver to perform the pick-up coil test. Several methods for evaluating the pick-up coil response to a series of test inputs of different frequencies are presented. These methods could be incorporated in a pick-up coil testing device that is independent of a receiver.

Abstract: Systems, methods, and devices are disclosed, including a ground-fault sensor that has a plurality of conductors each disposed one inside of another except for an outer conductor and a field sensor configured to sense an electric field, a magnetic field, or both. In some embodiments, the field sensor is disposed adjacent the outer conductor.

Abstract: An integrated circuit device includes a chip having a power supply terminal, a ground terminal, an input terminal, and an internal circuit formed therein. The chip comprises: a unidirectional device disposed between the input terminal and the ground terminal and directed from the ground terminal to the input terminal; and a ground open detection circuit including a first transistor having the gate connected to the input terminal and the source and the drain connected between the power supply terminal and the ground terminal, a second transistor having the gate connected to the ground terminal and the source and the drain connected between the power supply terminal and the ground terminal, and a comparator for comparing potentials of nodes respectively between drains of the first and second transistors and the power supply terminal, and for outputting a ground open detection signal.

Abstract: Systems, methods, and devices are disclosed, including a ground-fault sensor that has a plurality of conductors each disposed one inside of another except for an outer conductor and a field sensor configured to sense an electric field, a magnetic field, or both. In some embodiments, the field sensor is disposed adjacent the outer conductor.

Abstract: A polyphase source detecting circuit configured for detecting a polyphase source having three sources includes three sampling circuits and an alarm circuit. Each sampling circuit has a control switch. A control terminal of the control switch of each sampling circuit is connected to one of the phase sources of the polyphase source respectively. The alarm circuit has a first transistor, a first LED, and a buzzer. The anode of the first LED is connected to a power supply. The cathode of the first LED is connected to the base of the first transistor and connected to ground via the control switches of the sampling circuits in turn. The collector of the first transistor is connected to the power supply via the buzzer. The emitter of the first transistor grounded.

Abstract: The present invention provides a remote alarm panel display for monitoring wrist-strap cords used by an operator to install components during the manufacturing of hard disk drives in order to provide grounding to the operator as the operator handles electrically sensitive components and also to provide mobility to the operator within the assembly floor. In one embodiment, the remote alarm panel display comprises a plurality of alarm indicators which are activated when a corresponding wrist strap is disconnected from a wrist strap monitoring device connected to the remote alarm panel display. In one embodiment the alarm indicators are light emitting diodes.

Abstract: An apparatus and method detects an open condition of a grounding path provided by a rotor grounding brush electrically connecting a rotor body of a rotor to electrical ground. The rotor includes an insulated field winding wrapped around the rotor body and is configured to generate a magnetic field upon receipt of an exciter voltage across lower and upper extremities of the insulated field winding. The method includes applying a square wave voltage signal to a second end of each of a first and a second buffer resistor, where a first end of each of the buffer resistors is operatively connected to respective upper and lower leads of the exciter voltage source, and calculating the total capacitance between the insulated field winding and electrical ground. The total capacitance when compared to a pre-selected capacitance value is determinative of the absence of the grounding path.

Abstract: A polyphase source detecting circuit configured for detecting a polyphase source having at least two phase sources includes at least two sampling circuit and an alarm circuit. Each sampling circuit has a control switch. A control terminal of the control switch of each sampling circuit is connected to one of the phase sources of the polyphase source respectively. The alarm circuit has a first transistor, a first LED, and a second LED. The anodes of the first and second LEDs are connected to a power supply. The cathode of the first LED is connected to the gate of the first transistor and connected to ground via the control switches of the sampling circuits in turn. The cathode of the second LED is connected to the drain of the first transistor. The source of the first transistor grounded.

Abstract: A method of testing live AC circuits for neutral-ground, neutral-isolated ground, and isolated ground-ground faults, involves measuring impedances of circuit portions, including hot-neutral, neutral-ground, neutral-ground and isolated ground loops. In general either a test current generating a driving voltage is used, or in the case of hot-neutral, a load current generating a load voltage, and the voltage without current are use to measure voltage drop. These voltages are proportionate to the impedances of the circuits, which are expressed as ratios indicating the presence of faults. The method is reliable, despite much variation in circuit characteristics, including oversized neutral, shared neutral same phase, shared neutral opposed phase, supply line impedance, and high impedance grounds, it is easily able to detect faults across conductors and shared neutral loads.

Abstract: Described is a ground loop locator. A readout on the ground loop locator indicates the presence of a ground loop when a ground loop exists in conductors linked by a current transformer of an exciter portion and a Rogowski coil of a detector portion. Also described are how to make and use the ground loop locator and methods of use for the ground loop locator.

Abstract: Methods for detecting wet arc faults are based on the direct current (DC) signature analysis and pattern matching pertaining to wet arc characteristics. While magnifying some wet arc fault signatures, it may be found that the wet arc current signal itself resembles a normal current signal in both time and frequency domains. The change in magnitude or high frequency behavior found may not be enough to distinguish a wet arc fault signature from a normal signature. Embodiments of the present invention may look at the magnitude change in the DC content per cycle of the wet arc current signal, which may be more positive in one cycle while, in the next cycle, it may be negative in a relative manner. A particular number of these changes may be determinative of a wet arc fault.

Abstract: A method, apparatus and computer program for detecting an AC chassis fault on one or more DC/AC converters having a load is disclosed, including receiving a chassis voltage VChassis signal from between DC link and a chassis ground from the DC/AC converter, capturing a side band harmonic of the chassis voltage VChassis signal, determining a peak magnitude value related to the side band harmonic, comparing the peak magnitude value to a predetermined threshold value, wherein if said peak magnitude value equals or exceeds the predetermined threshold value, an AC chassis fault condition is detected.

Abstract: A method of detecting a ground fault condition between a direct current power system and the chassis ground of an electric or hybrid-electric vehicle is provided. The method includes sequentially opening and closing a first switch connected between a positive node of the direct current power system and the chassis ground of the vehicle and a second switch connected between a negative node of direct current power system and the chassis ground. The sequential opening and closing of the first and second switches charges and discharges an inherent capacitance present between the metal components of the direct current power system and the chassis. First and second currents are created as the inherent capacitance is charged and discharged. Measurements of the created first and second currents are then used to determine whether a ground fault condition exists between the direct current power system and the vehicle chassis ground.

Abstract: Test methods and components are disclosed for testing the quality of the ground connection fabrication process for ESD shunt resistors in magnetic heads. A wafer is populated with one or more test components along with magnetic heads. The test components are fabricated with ESD shunt resistor ground connections created by the same or similar process used to fabricate the ESD shunt resistor ground connections in magnetic heads on the wafer. The resistance of the test component ground connections may then be measured in order to determine the quality of the ground connections formed by the fabrication process. The quality of the ground connection fabrication process may then be determined based on the measured resistance of the test components.

Abstract: A method of testing a cabling system is disclosed. The method may include discharging an input filter capacitor associated with an accessory component, charging an accessory bus capacitor to a desired voltage level, and connecting the accessory bus capacitor to the input filter capacitor. The method may also include continuously monitoring a voltage waveform associated with the accessory bus capacitor. The method may further include determining a difference between the voltage waveform and a nominal voltage profile, and detecting a fault if the difference is greater than a threshold value.

Abstract: The present invention is directed to a protective wiring device for use in an electrical distribution system. The device includes a plurality of line terminals and a plurality of load terminals configured to be coupled to the plurality of line terminals in a reset state. A detector circuit is coupled to the plurality of line terminals. The detector circuit is configured to generate a detection signal in response to detecting at least one predefined perturbation in the electrical distribution system. A circuit interrupter assembly is coupled between the plurality of line terminals and the plurality of load terminals. The circuit interrupter assembly is configured to decouple the plurality of line terminals from the plurality of load terminals in response to the detection signal. An end-of-life mechanism is coupled to the detector circuit. The end-of-life mechanism is configured to permanently decouple the plurality of line terminals from the plurality of load terminals in the absence of an intervening signal.

Abstract: Systems and methods for detecting ground fault at the common DC bus in a high impedance ground system. A fault detection component can detect characteristics of an electrical signal including phase number (n) and fundamental frequency (H). A fast Fourier transform is performed at (n×H) and (2n×H), and the two values are compared. A healthy system (no ground fault) can display a large difference between (n×H) and (2n×H), while in an unhealthy system the difference can be minimal. A system and method of detecting variable phase number and fundamental frequency can be used in the calculation to perform the ground fault detection when these characteristics are variable.

Abstract: An apparatus for monitoring a circuit breaker includes an electronics unit, the electronics unit being configured to generate a re-occurring signal, and a self-test trip unit in signal communication with the electronics unit and being configured to receive the re-occurring signal and effect tripping of the circuit breaker.

Abstract: Systems, methods, and devices are disclosed, including a ground-fault sensor that has a plurality of conductors each disposed one inside of another except for an outer conductor and a field sensor configured to sense an electric field, a magnetic field, or both. In some embodiments, the field sensor is disposed adjacent the outer conductor.

Abstract: There is provided a state detecting method adopted to an insulation resistance detector including the steps of: calculating a difference between the output of the filter when a pulse signal having a first pulse width is applied to the series circuit, and the output of the filter when a pulse signal having a second pulse width shorter than the first pulse width is applied to the series circuit; and detecting the state of the insulation resistance detector based on the calculated difference.

Abstract: A method for detecting a ground fault in an electrical supply system includes using a combination of components and their connections within the supply system to form virtual components, allowing presetting of fault indicators for incoming and outgoing supply lines to individual components. A fault index can be determined for each virtual component in conjunction with a respective association of a correlation coefficient with fault indicators and a subsequent normalization over all fault indicators using a correlation coefficient. Comparison of the indices of all virtual components of the supply system permits a determination of that virtual component in which the highest fault index occurs, and therefore in which there is the highest probability of a fault. The fault search in a supply system can therefore be determined quickly and easily independently of power supply system geometry and configuration. An apparatus performing the method and computer program product, are also provided.

Abstract: A method, system and apparatus for determining a distance of a phase-to-earth fault on a three-phase electric line (30), the apparatus (40) being configured to determine a first estimate value for a distance between the measuring point (40) and a point of fault (F) on the basis of a first equation based on a fault loop model of the electric line, in which model the load of the electric line is located between the measuring point and the point of fault; determine a second estimate value for the distance on the basis of a second equation based on a fault loop model of the electric line, in which model the point of fault is located between the measuring point and load of the electric line; and select, according to predetermined criteria, one of the determined two estimate values as the distance between the measuring point and the point of fault.

Abstract: The present invention relates to a ground fault detection arrangement for a synchronous three-phase electrical machine, and an electrical system comprising a ground fault detection arrangement and a synchronous three-phase electrical machine. The ground fault detection arrangement injects an off-nominal frequency voltage between a neutral point of the synchronous three-phase electrical machine and ground and measure resultant currents to detect a ground fault.

Abstract: Systems and methods are disclosed for detecting a faulty ground strap connection for a machine hosting a high voltage system. In one embodiment, a fault detection and compensation system includes a ground strap, a DC power supply electrically referenced to a machine frame, a leakage detection switch connected to the machine frame, a current source controlled by the leakage detection switch, and a voltage measuring device that measures an offset voltage. The fault detection and compensation system further includes a leakage detection and compensation controller that compensates for the unbalanced fault condition by controlling the leakage detection switch and the current source, and determines whether the ground strap is properly connected to the machine frame.

Abstract: The “Ground Resistance Test” provides a circuit and test setup for measuring the resistance of earth grounds. The ground resistance test uses the central office battery from a working telephone pair to source current into the “Tested Ground”. First the quiescent voltage (Vo) on the Tested Ground with respect to a removable ground rod is measured and recorded. Then the ring side of a working pair is connected to the Tested Ground and the office battery draws current (I) from the Tested Ground. The voltage (Vi) on the Tested Ground with respect to the removable ground rod is again measured with dc current flowing. Voltage fall Vf is computed as (Vi?Vo). The ohms (R) of the Tested Ground is then displayed as R=Vf/I. In the event that central office battery is unavailable, the Ground Resistance Tester will provide an optional current rod and internal battery source.

Abstract: A method and system to detect and evaluate improper grounding/grounded bonds in an electrical power system is disclosed. An example method is detecting improper grounding in an electrical power system having a plurality of monitoring devices coupled to a grounded conductor and a grounding conductor. Data of the voltage between the grounded conductor and the grounding conductor is received from the plurality of monitoring devices. The spatial orientation of the data from the plurality of monitoring devices is determined within a hierarchy of the electrical power system. The voltage data received from the plurality of monitoring devices is compared to determine a bond (or lack of a bond) between the grounded conductor and the grounding conductor.

Abstract: A controller having discrete driver circuitry for driving an electrical load and a method are provided. The controller includes a microprocessor having ports configurable to operate as inputs or outputs. The controller also includes discrete driver circuitry connected to ports of the microprocessor. The discrete driver circuitry is configured to apply electrical power to drive an electrical load. The controller further has logic for configuring the ports of the microprocessor as an output to enable on/off of the output signal that drives the electrical loads, and further for configuring the ports of the microprocessor as an input to receive feedback signals from the discrete driver circuitry. The feedback signals are processed to detect fault conditions.

Abstract: A circuit breaker having a series arc fault detector and method of operation is provided. The series arc fault detector measures the RMS current and monitors current stability in response to a change in current levels. The sensitivity of the series arc fault detection is changed in response to the current satisfying a stability criterion. The circuit breaker further enables and disables series arc fault detection based on an enable threshold. The enable threshold is set based on the level of sensitivity being used to detect a series arc fault.

Abstract: Apparatus includes an arc wave generator for testing an arc fault circuit interrupter (AFCI) for use in a test system for testing whether or not an arc fault circuit interrupter (AFCI) is operating normally, in which a false arc is generated for use in testing the arc fault circuit interrupter (AFCI). The arc wave generator includes a rectifier which receives a commercial power source as an input source and rectifies alternating-current voltage of the commercial power source to generate a rectified signal. A drop resistor drops the voltage of the rectified signal to generate a voltage-dropped signal. A mono-stable multivibrator adjusts a voltage level and a pulse width of the voltage-dropped signal and generates a pulse signal which is used to generate a false arc for testing the arc fault circuit interrupter (AFCI). Thus, a false arc is generated with a simple circuit to accurately test the actions of the arc fault circuit interrupter (AFCI).

Abstract: A self-test circuit is provided that includes a signal circuit adapted to periodically output a circuit inhibitor signal to inhibit a breaking signal from a ground fault detector. The signal circuit is also adapted to periodically output a test signal simulating a ground fault. The self-test circuit also includes an alarm circuit adapted to receive an output signal from the ground fault detector in response to detecting the ground fault, and adapted to output an alarm when the ground fault detector is not operative. The signal circuit may be further adapted to periodically output a second test signal simulating a grounded neutral condition. A ground fault circuit interrupter system and a method are also provided.

Abstract: Methods to test the operation of the pick-up coil without having to de-energize the power line serving as the power line carrier in order to perform testing on the pick-up coil. A series of test frequencies are introduced and parameters of the pick-up coil can be measured to detect the presence or absence of resonant behavior indicative of the health of the pick-up coil. Testing capabilities may be incorporated into a power line carrier receiver and use the connections between the pick-up coils and the receiver to perform the pick-up coil test. Various methods are disclosed for evaluating the pick-up coil response to a series of test inputs of different frequencies. These methods could be incorporated in a pick-up coil testing device that is independent of a receiver.

Abstract: The invention refers to a method and an apparatus (1) for protecting people against leakage currents while using appliances such as home appliances or the like. The apparatus (1) is provided with a differential switch (20) normally open and a differential current transformer (39) which generates a signal proportional to the leakage current, an elaboration unit (50) interfaced with the latter acquires said signal and keeps the switch (20) closed until a dangerous condition is met, corresponding to an acquired signal having a magnitude greater than a limit value.