| 摘要 |
PURPOSE:To ensure a protecting operation by determining that a short-circuit failure occurs in a main rectifier, when an output voltage of the main rectifier becomes a prescribed value or below and a current of a main motor becomes also a prescribed value or below. CONSTITUTION:When both of a voltage relay 13 and a current relay 11 are off for a prescribed time or longer, the current of the current relay 11 becomes small and also the output voltage of a main rectifier 2 becomes small. It is regarded, therefore, that a continuity failure occurs in some of diodes 2A to 2F, and an auxiliary relay 16 is turned on through an on-delay timer 17. When the auxiliary relay 16 turns on, a relay contact 16A turns on while a relay contact 16B turns off, and breaker coils 3 and 6 are demagnetized. Breaker relay contacts 3A and 6A are turned off, an input to a main generator 1 is thereby interrupted and an input to a main motor 4 is also interrupted. Accordingly, a false operation of a short-circuit failure is eliminated and a protecting operation can be ensured. |
