Relay tester having a circuit to sense the voltage spihe caused by the armature movement

摘要

A computerized relay tester is provided which comprises a bar code reader, a test circuit for determining an actual value of an operational characteristic of the relay, and a memory for storing reference values for the operational characteristic for a plurality of relays. The test circuit is operative to automatically measure the actual voltage or current values at which "pickup" or "drop away" occurs in the relay under test, by sensing an inductive voltage "spike" caused by movement of the relay armature. Based on signals from the bar code reader, a reference value for the particular operational characteristic under test are retrieved from memory. The actual value is then compared with the reference value to determine whether the relay is functioning properly, and the relay tester outputs an indication of the operational state or condition of the relay.