A circuit breaker is a manually or automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition and interrupt current flow. In addition to providing a means to open and close its contacts manually, a circuit breaker must automatically open its contacts when an overcurrent condition is sensed.
The trip unit is the part of the circuit breaker that determines when the contacts will open automatically.
In a thermal-magnetic circuit breaker, the trip unit includes elements designed to sense the heat resulting from an overload condition and the high current resulting from a short circuit.
The Eaton Cutler Hammer 140D481G03 Secondary Injection Test Set is used to test and verify the pickup levels and time delay settings of a breaker’s trip unit. The 140D481G03 is also used to test Amptector, Digitrip, RMS or Optim trip units.
The Eaton Cutler Hammer 140D481G03 Secondary Injection Test Set passes enough current to check any desired calibration point, allowing the solid-state trip unit operation to be checked without using primary current. The breaker must be de-energized before checking the operation of the solid-state trip units. If the 140D481G03 shows that the solid-state trip unit is not functioning properly, the trip unit should be replaced.
Each Protec office stocks a full complement of electrical test and measurement equipment. Offering equipment from all of the premiere manufacturers for rent, lease or purchase, Protec has the electrical testing equipment you need to get the job done.