Zur Speisung einer elektrolytischen Arbeitsvorrichtung dienender regelbarer Konstantspannungs-Generator

摘要

1353232 Protective arrangements ROBERT BOSCH GmbH 18 Aug 1971 [19 Aug 1970] 38650/71 Heading H2K [Also in Division G3] A supply system for an electrolytic machining apparatus includes an amplifier 23 which receives as inputs a first signal proportional to output current by way of an amplifier 32, and a second signal dependent on the derivative of output voltage formed by a differentiating circuit 25. In the event of gradual increase in current beyond a value determined by a potentiometer 24, or an external short circuit, the amplifier 23 causes a circuit breaker unit 22 to actuate a thyristor short 21 connected across the secondary of an isolating transformer 20. At the same time, a series transistor unit 27 is blocked through a voltage regulator 36, and a switch 38 is actuated to divert base current from the unit 27. A diode 29 short circuits voltage peaks due to external inductance. The circuit breaker 22 may reclose the circuit after a delay, but if short circuit conditions are again detected, the supply is shutdown finally.