| 摘要 |
In the event of faults, a fail safe circuit FS is operative to energise a battery charge warning lamp LK and to switch connection of the generator field winding from a main regulator Re1 to a standby regulator Re2. A conductively defective main regulator state is detected when circuits 3 and 4 simultaneously give a high output to AND gate 5. Circuit 3 senses continuous field winding excitation by detecting a low average voltage on a terminal DF1, and the circuit 4 responds to the voltage at a terminal D+ being above a maximum value. Lamp LK is also energised and regulator Re2 brought into use if a circuit 6 senses interruption in field winding excitation. If the D+ terminal voltage drops below a first reference level, circuit 6 causes a load to be connected to that terminal for a preset period. If the D+ terminal voltage then drops below a second reference, lower than the first, then circuit 6 outputs a high signal to OR gate 2 to effect the change over to the standby regulator Re2. Gate 2 latches in the standby regulation state in response to a high output from gate 5 or from circuit 6. The fail safe circuit FS can be used with a generator having zener diodes Z in at least one of its rectifier bridges G1. When the ignition switch ZS is first switched on, a circuit 1 acts to switch the regulator changeover relay 8 back and forth once to effect cleaning of the relay contacts. <IMAGE>
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