| 摘要 |
PURPOSE:To make it possible to prevent unnecessary repetition of connection and disconnection load by setting respectively disconnection voltage of load and connection voltage of load according to whether an external power supply is connected or not. CONSTITUTION:When battery voltage drops to -42V after the elapse of specific time since the service interruption occurs, a voltage monitoring circuit 11 detects the lowering of battery voltage to turn a transistor 12 OFF, and relay contacts 4a and 4b are opened to disconnect load 6. After that, at a point when battery voltage rises from -42V, the voltage monitoring circuit 11 is operated again to turn the transistor 12 ON, a relay 4 is not excited because a transistor 9 maintains its OFF state, and load is not connected. When the service interruption is repaired, a power monitoring relay 13 is excited, a contact, 13a is closed to detect immediately voltage rising by a voltage monitoring circuit 8, the relay 4 is excited to connect load and, at the same time, detection voltage of the voltage monitoring circuit 11 reaches -21V, and the transistor 12 also maintains its ON state. |
