The present disclosure relates to an electronic circuit for detecting the current winding temperature of phase windings and/or other characteristics of an electronically commutated electric motor, which is connected, or can be connected, to a frequency converter, comprising one or more capacitive two-terminal networks with a temperature-dependent impedance, each network being arranged parallel to two winding terminals (u, v, w) of the phase windings, as well as a detector for detecting the current responses in the motor feeds on the basis of steep-flanked voltage changes at the output of the frequency converter.

An arrangement for injection-based ground fault protection handling including a number of stator windings of an electric machine that are connected to a neutral point, a first transformer including at least one primary winding connected to at least one measurement point of the stator windings and at least one secondary winding for measuring an electrical quantity of the machine at the measurement point. There is also a second transformer having a primary winding connected between the neutral point and a ground potential and a secondary winding for connection to a signal generation and detection unit in order to inject a signal into the neutral point and receive a response. The impedance of the second transformer is in the range of the impedance of the machine.

Polarizing signals for electric power system directional overcurrent and distance protection are disclosed herein. The polarizing signal may be determined using a power system tracking signal, generated using a synchronous reference frame to track to a pre-fault voltage, and maintained using a phase-locked loop. The power system tracking signal may be used for a time after a voltage signal is lost, after which a self-polarizing signal may be used. Where voltage signals are not available, a current may be used to generate the polarizing signal.

An electrical fault detector is shown for installation in electrical network (101) of the type comprising a first voltage source (104) and a second voltage source (107), each of which have a respective positive rail (105,108) connected by a positive concentrator (110) and a respective negative rail (106,109) connected by a negative concentrator (111). The detector comprises an inductor (112) for location in one of: the positive concentrator between the connections of the positive rails thereto, and the negative concentrator between the connections of the negative rails to thereto. The detector also comprises a fault identification device (113) configured to monitor the voltage across the inductor, and generate a fault signal in response to the voltage across the inductor exceeding a threshold.

Systems and methods for testing a lightning protection circuit are provided. Aspects include providing an alternating current (AC) test signal source coupled to a circuit under test, the circuit under test comprising a lightning protection circuit having a threshold voltage, a first filter, and a second filter, providing a direct current (DC) voltage supply in series with a filtering device, the filtering device coupled to the AC test signal source, providing a first capacitor coupled between the AC test signal source and the circuit under test, operating the DC voltage supply and the AC test signal source to provide a first test signal to the circuit under test, wherein the first test signal comprise a first voltage that exceeds the threshold voltage, measuring a first impedance of the circuit under test responsive to providing the first test signal, wherein the first impedance corresponds to the first filter.

In one embodiment, an aircraft electronics system includes a hardware processor, a charge collection circuit to collect charge; a switching circuit controlled by the hardware processor to discharge the charge collected on the charge collection circuit through a bonding circuit formed from a chassis and a bonding surface; and a voltage measurement circuit to measure a voltage difference between measurement terminals across the chassis and the bonding surface.

A current leakage detector for detecting current leakage between a power source and a load including a first sensing coil and a second sensing coil positioned opposite the first sensing coil. The current leakage detector further includes a magnetic field sensor proximate the first sensing coil and the second sensing coil and the magnetic field sensor has a response range. The current leakage detector also includes a bias circuit configured to adjust the response range of the magnetic field sensor. A method for detecting current leakage includes providing a first sending coil and a second sensing coil. The method continues with the steps of providing a magnetic field sensor in proximity to the first and second sensing coils and providing a bias circuit. The method continues with the step of utilizing the bias circuit to place the response of the magnetic field sensor within a preferred response range.

A current leakage detector for detecting current leakage between a power source and a load including a first sensing coil and a second sensing coil positioned opposite the first sensing coil. The current leakage detector further includes a magnetic field sensor proximate the first sensing coil and the second sensing coil and the magnetic field sensor has a response range. The current leakage detector also includes a bias circuit configured to adjust the response range of the magnetic field sensor. A method for detecting current leakage includes providing a first sensing coil and a second sensing coil. The method continues with the steps of providing a magnetic field sensor in proximity to the first and second sensing coils and providing a bias circuit. The method continues with the step of utilizing the bias circuit to place the response of the magnetic field sensor within a preferred response range.

A circuit for alternating current and direct current leakage detection. The circuit can achieve multiple functions such as direct current leakage detection, alternating current leakage detection, and leakage sampling link self-check. The circuit mainly comprises: an LDO module for converting an externally input power supply voltage into a voltage required for leakage detection; a frequency divider module for performing frequency division on a high-frequency clock signal; a logic control module for driving an MOS transistor and controlling the switching of different working modes; an MOS transistor driving module for driving an external leakage detection coil; a leakage detection coil for inducing alternating current and direct current leakage signals and a leakage self-check signal; a sampling resistor for converting the current signal flowing through the leakage detection coil into a voltage signal; a PGA module for amplifying a sampling signal; a gain control module for controlling a PGA amplification factor; an ADC module for performing digital-to-analog conversion of the signals; a DSP module for processing the alternating current and direct current leakage signals and the leakage self-check signal; and a current limiting module for limiting a loop current.

A system for monitoring the state of a cable, includes a plurality of transferometry devices capable of injecting a test signal into the cable and measuring a signal being propagated in the cable, the transferometry devices being positioned along the cable so as to break down the cable into successive sections, the system comprising a control member capable of communicating with the transferometry devices and configured so as to perform at least one transferometry test consisting in injecting a test signal into the cable by means of a first transferometry device and measuring the test signal after its propagation in the cable by means of a second transferometry device different from the first device, the system comprising a post-processing member capable of communicating with the transferometry devices and configured to compare the measured signal to a reference signal to deduce therefrom an indicator of degradation of the section of cable disposed between the first transferometry device and the second transferometry device.