| 摘要 |
<p>A first trip unit (5) for interconnection with a second trip unit (4,10) includes current transformers (16A,16B,16C,16G,16N) and potential transformers (26A,26B,26C) for sensing current, voltage and frequency conditions of a circuit breaker's separable contacts (44A,44B,44C). A microprocessor-based trip mechanism (28,30) provides a trip signal (40,49), which is employed by the circuit breaker's operating mechanism (42) to open the separable contacts (44A,44B,44C) as a function of the sensed electrical conditions and related predetermined operating values. The microcomputer's transceiver (36) communicates with the second trip unit (4,10) over a passive two-wire communication cable (3) to acquire the predetermined settings of the second trip unit (4,10). The microcomputer (28,30) includes a firmware routine (130) which employs the acquired predetermined settings as its predetermined values. <IMAGE></p> |
