| 摘要 |
PURPOSE:To detect a malfunction such as an increase in resistance value of a driving coil, a disconnection of the coil, or burning of a transistor by switching a current value supplied to the coil and detecting the voltage generated at this time. CONSTITUTION:A current controller 1 controls a transistor TR1 so that a current corresponding to a reference voltage supplied from a reference voltage switching circuit 3 flows to a resistor R1. and the circuit 3 supplies a voltage lower than a different reference voltage corresponding to a switching signal such as rated voltage to the controller 1. Malfunction detecting means 2 detects whether the voltage generated between a resistor R1 connected with the base of the transistor TR1 and a resistor R2 is abnormal or not, thereby discriminating whether a driving coil M4 is increased in its resistance value on heating, is disconnected, or the transistor TR1 is burnt. |
