Secondary Injection Test Set for Circuit Breaker Maintenance
Circuit breakers are devices that protect an electrical system from overload, over current, earth fault and power reversal. They have a magnetic coil that energizes at a predetermined level to pull the contacts and break the current flow. It can be reused several times by resetting the device. A circuit breaker can become faulty if the coils get damaged or the contacts weld itself together due to arcing. Routine maintenance is necessary to make sure they work properly.
There are several tests for circuit breakers. Primary injection is done by injecting the actual current required to energize the circuit breaker. This test makes the circuit breaker interrupt large currents thus shortening its life. A secondary injection test, on the other hand, is done by injecting a current with the contacts closed but with no current flowing on the poles. This is a better way of testing circuit breakers because it uses low voltage signals that are injected to the circuit breaker which prolongs the operating life.