Test and analysis of reliability for electromagnetic relay

As relays are widely used in automatic control systems and communication systems, the reliability of relays is very important. Electromagnetic relays, type 155, were tested for their reliability in this paper. The test load was DC 24 V/spl times/0.1 A. During the test, the contact voltage drop, closing time and opening time were monitored and measured. At the end of test, we estimated the reliability of the relay according to the test results and analyzed the failure mode. The failure mechanisms were analyzed by observing the surfaces of failing contacts. We proposed a method for reducing the relay failure rate.