| 摘要 |
PURPOSE:To effectively prevent the overrun of a brushless motor without affecting the influence to the rotating of a motor in the normal state by stopping or decelerating the rotation of the motor when a DC voltage in response to the position detection output of the motor exceeds the set reference voltage. CONSTITUTION:When any malfunction occurs at a rotating speed detector 5, a constant speed control becomes impossible, and the motor starts rotating at a high speed. An output is frequently produced by this high speed rotation in response to the rotation of the rotor 2 from a position detector 3. This position detection output is converted into a DC voltage through an amplifier 6, a waveform shaper 7 and a F/V converter 8, and becomes larger than the compared voltage Vref. Accordingly, an output is presented at a voltage comparator 9, a thyristor 11 is interrupted, and a power source to a motor drive circuit 1 is interrupted. |
