| 摘要 |
PURPOSE:To embody the rotary speed control of a motor with a simple circuit, by entering an output voltage of an amplification circuit and a zero cross point of commercial power source into a charging voltage of a CR timer which starts charge at the time of starting and a comparison circuit and triggering the power control elements of a thyristor or the like from said output signals. CONSTITUTION:A rotary speed of a motor in current use is incorporated as a pulse signal by a rotary speed sensor. The rotary speed is converted into a voltage signal equivalent to the rotary speed by an F/V conversion circuit 3. The voltage is compared with a preset constant voltage value. The differential voltage is amplified by an amplification circuit 10. On the other hand, a CR timer circuit 5, which starts charge with a zero cross point of commercial power source at a starting point, generates charging voltage which is subject to change with time, responding to its phase within the half wave of the commercial power source. When the charging voltage and the output voltage of the amplification circuit are entered into a comparison circuit 15, the circuit outputs the voltage converted into lag time from the zero cross point from the voltage of the amplification circuit. Therefore, a thyristor TRIAC 18, which drives the motor is triggered from this signal, the rotary speed of the motor can be feedback controlled. |
