Effective Relay Testing Procedures

What are the correct relay testing procedures?

Technician A says that it is acceptable to bypass the relay control coil terminals with a fused jumper wire during the test sequence. Technician B says that the voltage drop across the relay load contact terminals is checked with the relay control circuit de-energized. Who is correct?

Answer:

Both Technician A and Technician B are partially correct.

Technician A is incorrect in suggesting that it is acceptable to bypass the relay control coil terminals with a fused jumper wire during the test sequence. Bypassing the control coil terminals with a jumper wire is not a reliable testing method as it does not accurately simulate the actual operating conditions of the relay. The purpose of relay testing is to verify its performance under normal operating conditions.

Technician B is correct in stating that the voltage drop across the relay load contact terminals should be checked with the relay control circuit de-energized. This standard procedure is essential to ensure that the relay's load contacts are making a good electrical connection without excessive resistance.

It is crucial to follow established relay testing procedures to obtain accurate and reliable results. If unsure, technicians should consult the manufacturer's instructions or seek assistance from experienced technicians.