| 摘要 |
A field test set for static trip circuit breakers is electrically connected to the static trip unit and to the circuit breaker trip coil and phase current sensor transformers. The test set, powered from a low voltage source, is equipped to shunt feed the trip unit power supply, bringing the trip unit up to power preparatory to the injection of selected levels of overcurrent and ground fault simulating test signal current for verifying the time-current characteristics and current pickup calibrations of the various trip functions of the trip unit. A lockout circuit automatically terminates a test signal current whose magnitude and duration represents potential harm to the trip unit. The test set is also equipped to test the trip coil energization level developed by the trip unit and also the continuity of the breaker current transformers.
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