Study On Test System Of Electro-Dynamic Of AC Contactor

Contact is the weakest link of contactor，s reliability. Especially, the main contacts of ACcontactor are carrying large current when they switch on AC load circuit and break AC loadcircuit. The waveform of voltage and current of on-off process of contactor，s main contactscontain information that can reflect contactor，s performance, which can extract the electrical contactparameters and the time characteristic parameters from them. so we need to study test technology ofdynamic performance of AC contactor and measure dynamic voltage wave of contact. It isimportant to study the electric contact performance and reliability of contactor，s contact.This topic studies the test system of dynamic performance of AC contactor which is mainlybased on an industrial control computer. This test system can complete automatic measurementof voltage and current wave of AC contactor，s action course with corresponding test system. Thehardware system mainly includes the drive circuit of coil, the circuit of data acquisition andcontrol, voltage-current regulate circuit of coil, voltage-current regulate circuit of contacts andanalog load circuit. The drive circuit of coil and control circuit of data acquisition both adoptsSSR as control switch device. The data acquisition circuit chooses high-speed daq card. Theregulate circuit of contact，s voltage adopts double sensor parallel test program to realize theaccurate measurement of voltage value. The software system adopts LabVIEW graphicalprogramming language to modularize design. The main program mainly includes the drivecontrol subroutine of coil and the control subroutine of data acquisition, which realizecoordination control of coil drive and data acquisition of contactor.In addition, this topic studies the high-speed and real-time judgment algorithm of on-offstate of AC contactor under the condition of AC load.