A tester for a relay comprises an enclosure, a testing circuit that includes a controller, electronic switch components, a power source, indicator LEDs, a test start switch, a relay selector switch, and five electric leads each connected with one terminal of the relay. With the relay selector switch toggled to indicate the type of relay being tested, with power supplied to each lead, and with the test start switch actuated, the controller sets each lead to ground, in turn, and then count the number of other leads that are grounded as a result. The controller then illuminates the at least one indicator to indicate either the passing relay test or the failed relay test based on the counts measured. Once the leads connected to the relay coil are identified, cyclic testing of the relay can be performed.

The application provides an electrical system with online sampling and check function and its check method for high-voltage and medium-voltage electrical equipment, including electrical equipment, gas density relay, gas density sensor, valve, pressure regulating mechanism, online check contact signal sampling unit and intelligent control unit. The pressure is increased or decreased by the pressure regulating mechanism to enable the contact action of the gas density relay of electrical equipment. The contact action is transmitted to the intelligent control unit through the online check contact signal sampling unit. The intelligent control unit detects the alarm and/or blocking contact signal operating value and/or return value according to the density value of the contact action; the check of the gas density relay can be completed without maintenance personnel on site, which greatly improves the reliability of the power grid and the work efficiency, and reduces the O&M cost. At the same time, it also realizes the mutual self-inspection between gas density relay and gas density sensor, and further realizes the maintenance-free.

A vehicle includes a battery, a motor supplied with an input voltage, an inverter configured to boost the input voltage supplied to the motor to output to the battery, a voltage measuring device configured to measure the input voltage, a switching device connected to a neutral point of the motor, and a controller that determines whether fusion of the switching device occurs, repeats on/off of the switching device based on the determination result, measures a first voltage applied to the voltage measuring device, measures a second voltage applied to the voltage measuring device after discharging the voltage measuring device, compares the first voltage with the second voltage, and charges the battery when the fusion of the switching device is released based on the comparison result.

The relay safety system provided by the present invention includes a relay, an emergency stop device, a trigger detection circuit, a sticking detection circuit, and a power-off circuit. The emergency stop device is used to generate an emergency stop signal. The trigger detection circuit connects the relay and the emergency stop device, and is used to convert the emergency stop signal into a trigger signal. The sticking detection circuit is connected to the trigger detection circuit and the relay, and is used to detect the sticking signal generated by the relay, and generate a power-off signal according to the trigger signal and the sticking signal. The power-off circuit is connected to the emergency stop device, the relay and the sticking detection circuit, and receives the power-off signal, and disconnects the power of the relay according to the power-off signal.

The present disclosure relates to a device and a method for diagnosing a failure of an inverter initial charging circuit. The device for diagnosing a failure of an initial charging circuit according to the present invention is advantageous as follows: it is possible to detect whether a relay of the initial charging circuit is malfunctioning or not by using a photocoupler connected in parallel with an initial charging resistor of the initial charging circuit, on the basis that, if a current flows through the initial charging resistor in a relay-on state, the photocoupler is turned on; and it is possible to prevent component failure or burnout from occurring due to a high current flowing through the initial charging resistor in the case of a relay failure.

The invention discloses a field detection device and system for achieving no maintenance of a gas density relay. The field detection device comprises a temperature adjusting mechanism and an intelligent control unit, wherein rise and fall of the temperature of the temperature adjusting mechanism are controlled by the intelligent control unit, thereby making the temperature of a temperature compensation component of the density relay rise and fall to complete the field detection of the gas density relay, and no maintainer is needed to operate on site, which achieves no maintenance of the gas density relay, and greatly improves the efficiency and reliable and safe running of power grids. The invention further provides a field detection method for supporting normal running of the field detection device above.

The present application provides a gas density relay check device and a check method thereof, comprising a temperature adjusting mechanism, at least one pressure sensor, at least one temperature sensor, a computer data processing system and a contact signal sampling unit. In check, the temperature adjusting mechanism and the gas density relay are relatively set, temperature rise and fall of the temperature compensation element of the gas density relay is adjusted through the temperature adjusting mechanism, then the gas density relay is enabled to have a contact signal action, the gas density value is obtained according to the pressure value and the temperature value in the contact action, the contact signal operating value of the gas density relay is detected, and check on the contact signal operating value of the gas density relay is completed. The gas density relay check device of the present application is capable of accurately checking gas density relays of various measuring principles in various situations, and is particularly applicable to a gas density relay without a three-way valve, and check can be achieved without disassembling the gas density relay.

Testable sealed and/or self-diagnosing electromagnetic or solid-state relays simplify troubleshooting of electrical circuits. The testable relay comprises a relay housing with terminals adapted to connect to a circuit and an opposing top wall with testable terminals formed as projections being flush with or extending from the top wall and being exposed for testing the relay by applying a multimeter device. A self-diagnosing relay comprises a relay housing with terminals adapted to connect to a circuit, and at least two light-emitting diodes (LEDs). One of the LED indicates the relay is energized, and another LED light is a diagnostic LED and indicates if the relay is damaged.

The smart circuit breaker tester is a portable system for testing medium voltage circuit breakers. The system includes a programmable logic controller (PLC), a human machine interface (HMI), transducers for measuring current and voltage, an impedance tester, a smart power supply for supplying voltages required for testing circuit breakers with related power and safety components, and plug and play and OEM cables for connecting the system to the circuit breaker under test. The PLC is programmed with custom software that reports such testing criteria as closing time and closing drain current, opening time and opening drain current, contact resistance, etc. within about two minutes, and permits testing automatically in sequence or manually one at a time. The system permits testing in situ while the circuit breaker is still connected to the circuit(s) being protected, or when drawn out.

A relay abnormality diagnosis system and method capable of diagnosing an abnormality of a relay by directly connecting a diagnosis resistor to a current measurement unit and by using a current input to the current measurement unit from the diagnosis resistor and a current flowing on an electric circuit measured by the current measurement unit, in the relay abnormality diagnosis system that diagnoses the abnormality of the relay using the diagnosis resistor.