| 摘要 |
PURPOSE:To eliminate the need for Zener diodes for the prevention of cost increase and miniaturize equipment by judging that an abnormal voltage is applied to a load by a generation set, operating a semiconductor switch, and controlling switching in connection between a direct current power supply and the load. CONSTITUTION:A load (direct current motor) 2 and a direct current power supply (battery) 1 are connected/disconnected by a semiconductor switch 3. A voltage detecting means 8 and 9 detects the voltage VB0 applied to the load 2. A voltage comparing means 10 compares the detected voltage VB1 from the voltage detecting means 8 and 9 with a specified reference voltage. If the detected voltage VB1 exceeds the reference voltage, it is judged that an abnormal voltage is applied to the load 2 by a generation set 5. Then a switching control means 6a operates the semiconductor switch 3 to connect the direct current power supply 1 and the load, and absorbs energy from the abnormal voltage within the range of semiconductor switch 3 safety operation. |
