Research On Test System Of Dynamic Electrical Performance Of AC Electromagnetic Relay

When the electromagnetic relay is making, the voltage and current of the coil and thecontact is the most direct information to reflect the electromagnetic system, the spring system,the contact system performance and even the reliability of relay. Therefore, based on the voltageand current waveforms of the coil and the contact, researching time characteristic and electricalcontact properties of electromagnetic relay have great significance of studying the reliabilityabout relay. This paper researches the real-time and high-speed measurement technique of thevoltage and current waveforms in the making process of electromagnetic relay, and researchesthe technology of getting dynamic electrical performance characteristics.The paper designs the hardware test system of the electromagnetic relay, which can test thedynamic electrical properties. Hardware system is composed of the control circuit and thehigh-speed data acquisition circuit. The control circuit includes the drive circuit of theelectromagnetic relay and the sampling strobe circuit. The high-speed data acquisition circuit isconsisted of the contact voltage and current acquisition circuit, the coil voltage and currentacquisition circuit. In the hardware system, advantech “IPC-610-L” type IPC is regarded as thehost of the control system, which controls the PCL-720+digital I/O card, outputting the drivingsignal of the test samples and the signal of channel strobe, and controls the data acquisition cardPCI-1742U to acquire analog signal of the voltage and current at real time.The paper designs the software test system of the electromagnetic relay, which can test thedynamic electrical properties. The software system uses Visual Basic language. The softwaresystem is consisted of a parameter setting program, a control program, an acquisition programand a display program etc. The parameter setting program is responsible for system parametersetting. The control procedures include the test sample’s driver subroutine and sampling strobesubroutine. The collection procedures include voltage and current collection subroutines of thecoil and contact. The display programs include waveforms display and adjustment subroutines.The paper uses multi-resolution analysis and wavelet denoising to analyze the acquiredvoltage and current waveforms. Then, according to the denoised waveforms of the contactvoltage and current, the paper calculates the dynamic resistance waveform of the contact duringthe making process of electromagnetic relay.