Do initial screening tests have any effect on the reliability of relays during the use life?
Yes. Screening tests detect those failures, which would otherwise occur during the early life of a relay. This is why it is important to know what screening tests are performed by the manufacturer. • Is there more than one method used to calculate relay reliability failure rates? Yes. There are several methods used to calculate relay failure rates. The accepted method and three other methods that are sometimes used to enhance a particular failure rate are shown in Figure 1. Method Total Operations Failures *Failures Rate A C C E P T E D Terminate testing with a failure and one operation is one coil energized and de-energized cycle. 10,000,000 6 0.600 S O M E T I M E S U S E D Teminate testing without a failure and one operation is one coil energized and de-energized cycle 10,000,000 5 0.500 Teminate testing with a failure and one operation is a contact make/break per coil energize and de-energized cycle 80,000,000 6 0.075 Teminate testing with a failure and one operation is a contact m
