| 摘要 |
<p>A differential tripping circuit (11) comprises a summing transformer (30) associated with a tripping relay (36), a test circuit (38) having a test interruptor (50) with test button (52), and a remote- control opening circuit (60, 58) attached to terminals (54, 56) accesible from outside. The core (32) of the transformer (30) is equipped with two auxiliary windings (66, 68) connected in series in the test circuit (38) so as to magnetise the core (32) in the event of a defect of isolation of the remote-control circuit relative to earth. The isolation protection threshold of the remote-control circuit (60, 58) is at least equal to the sensitivity of the apparatus (10). Application: interruptors or differential circuit breakers. <IMAGE></p> |
