| 摘要 |
<p>A trip circuit supervision circuit is disclosed for use in combination with a trip circuit comprising a circuit breaker trip coil (102) connected in series in a supply line from a supply voltage and a trip relay contact (101) connected in series with the circuit breaker trip coil (102) in the supply line, the trip circuit supervision circuit being connected across the relay trip contact (101) and including a current sensing device (107), characterised in that during normal operation the supervision circuit is adapted to draw a substantially constant current from the supply line independent of supply voltage fluctuations when the relay trip contact (101) is open, and in which the current sensing device (107) produces an output signal dependent upon the current drawn by the supervision circuit. <IMAGE></p> |
