| 摘要 |
PURPOSE:To detect securely the breaking of wire of a tachometer generator by outputting a wire breaking detection signal on the basis of the results of detection for detecting a voltage higher than a specific value being applied to a DC motor, and detection for the output voltage of the tachometer generator being smaller than a specific value. CONSTITUTION:When the DC motor 2 rotates, the tachometer generator 3 outputs a voltage proportional to its rotation, and the output of an operational amplifier 12 goes down to a low level when the output voltage exceeds the voltage division value of resistances R4 and R5. On the other hand, when the output volt age of the generator 3 exceeds the negative voltage division value of resistances R6 and R7, the output of an operational amplifier 13 goes down to a low level; when the voltage proportional to the driving voltage applied to an operational amplifier 11 exceeds the voltage division voltage of resistances R3 and R4, the output of the operational amplifier 11 goes up to a high level. Therefore, when the driving voltage is applied to rotate the motor 2 and the output of the generator 3 within a specific range goes down almost to 0V, a tri-input AND element 14 outputs the wire breaking high-level signal of the generator 3, and the breaking of wire of the tachometer generator is detected securely without recognizing erroneously that the low-speed rotation of the motor 2 is the breaking of wire. |
