Strategy of Eliminating Contact Bounce Using TRIAC for AC Contactor

Abstract

In the operation of the contactor, contact bounce at closing period is an important factor affecting the performance and electrical life of the contactor. To improve the service life of the contactor by reducing the core impact and contact bounce when the AC contactor is closing, dynamic characteristics of the contactor have been analyzed and various excitation control methods have been invented to reduce the contact bounce. In this paper, a novel DC excitation circuit using TRIAC and a current control strategy based on the phase control to reduce the contact bounce for AC contactor are proposed. The dynamic characteristics of the proposed electromagnetic system are analyzed. Simulation of the proposed circuit and control scheme is implemented by MATLAB/SIMULINK and ADAMS for a 63A AC contactor. The simulation results show that the proposed DC excitation circuit and coil current control scheme can control the current through the contactor coil and the speed of the moving part of the contactor and can reduce the contact bounce during collision of the contactor by phase control to the TRIAC.