Measurer of Three Phase Synchronous Time for Vacuum Contactor

In order to solve the problems of difficulty in adapting vacuum contactor’s 3 phase contact acting synchronousness,and unableness to detect when contact touches resistor,a portable digital measurer is developed,which may be used to measure the synchronous time of 3 phase contacts closing or breaking,as well as to measure the micro resistance after contacts close.In the paper,the author details the performance and working principle of the instrument.