A device for detecting stray electrical currents in fluid mediums comprises at least two probes for partially disposing in a fluid medium and a control unit. The control unit comprises at least one analog-to-digital signal converter in electrical communication with at least one of the probes, at least one audio-visual alarm, and a processor operably coupled to the at least one converter and to the at least one audio-visual alarm. The processor is operable to measure an electrical potential difference between the two probes, to analyze a plurality of the measurements to determine whether a predetermined frequency is present, and to transmit an alert signal to the audio-visual alarm if the predetermined frequency is present. Advantageously, by monitoring for the frequency, the device more consistently and more reliably detects the presence of stray alternating currents.

The invention relates to a measurement system for detection of conduction faults of a device or equipment, comprising an evaluation unit and at least one sensor unit, wherein the measurement system is furthermore adapted to determine, in regard to a fault, whether the fault is higher or lower in frequency with respect to a predetermined limit frequency, and the measurement system is furthermore adapted to provide data in regard to one fault or multiple faults.

A current control device brings, after a target current has been changed to an upper side, a solenoid into a full-on state at a first timing that arrives in a predetermined control transition cycle shorter than an on-off cycle, determines whether an excitation current has become equal to or larger than a full-on threshold larger than the target current, brings the solenoid into a full-off state at a first timing that arrives in a predetermined energization switching cycle shorter than the on-off cycle after the excitation current has become equal to or larger than the full-on threshold, determines whether the excitation current has become equal to or smaller than a full-off threshold smaller than the target current, and causes a transition to a steady control at a first timing that arrives in the control transition cycle after the excitation current has become equal to or smaller than the full-off threshold.

A lock-in amplifier includes a clock signal generator configured to generate a first demodulation clock signal and a second demodulation clock signal having a phase difference of 90 degrees and a same demodulation frequency; and a detector configured to, based on an input signal, the first demodulation clock signal, and the second demodulation clock signal, provide an offset voltage corresponding to an offset of the lock-in amplifier in a first operation mode, and provide a first output voltage and a second output voltage, each of which correspond to a demodulation frequency component of the input signal in a second operation mode.

Example embodiments of the invention include a powdered core bead body configured to become an inductive impedance to current signals in a power wire with high frequencies. The signals are detectable by a high frequency voltage sensor, which is configured to output an arc fault tripping indication to an arc fault tripping circuit. The bead body includes a magnetic flux-density sensing device embedded in an air cavity of the bead body, having a magnetic field sensing surface oriented substantially perpendicular to the circumferential periphery of the bead body. The bead body is configured to provide measurable magnetic flux through the magnetic flux-density sensing device, for currents in the power wire having low frequencies. The measurable magnetic flux is detectable by a low frequency magnetic flux-density sensing device, to output a low frequency current measurement for power metering devices or to determine power consumption within a protected branch.

Example embodiments of the invention include a powdered core bead body configured to become an inductive impedance to current signals with high frequencies in a power wire threaded through the powdered core bead body. The signals are detectable by a high frequency voltage sensor that is configured to output an arc fault tripping indication to an arc fault tripping circuit in response to an occurrence of high frequency current signals in the power wire.

A vehicle includes: a plurality of electric loads that consume the dark current during parking of the vehicle and modulate the dark current; a battery sensor that senses the dark current output from a battery, demodulates the dark current modulated by the plurality of electric loads, identifies the dark current consumed by each of the plurality of electric loads based on the demodulated dark current, and identifies an electric load, which consumes excess dark current, based on the dark current consumed by each of the plurality of electric loads; and an integrated control device to alert a driver of consumption of the excess dark current of the identified electric load.

In some embodiments, a circuit may include an input configured to receive a signal and a radix-r fast Fourier transform (FFT) processing element coupled to the input. The radix-r FFT processing element may be configured to subdivide data of size N into r equal sub-domains of size N/r1 to determine specific frequencies.

A current detector and a detection unit are provided. The current detector is connected to at least one of drive current lines of a rotary machine. The detection unit performs an orthogonal detection on a main frequency detected by the current detector, and extracts a magnitude of a sideband wave. Then, a state of the rotary machine is diagnosed from the magnitude of the extracted sideband wave.

A current estimation device according to an embodiment of the present disclosure is a device for estimating a charging/discharging current of a battery pack and includes: a shunt resistor connected between a first node and a second node on a charging/discharging path of the battery pack; a shunt capacitor connected between the first node and the second node; a voltage measuring unit connected between the first node and the second node to measure a voltage applied to the shunt resistor; and a current estimating unit configured to estimate the charging/discharging current of the battery pack by using the voltage measured by the voltage measuring unit.