| 摘要 |
PURPOSE:To enable a motor to reach a constant speed state in changing its speed and in reversing its direction within the shortest time, by changing the time constant or amplification degree of a smoothing circuit both in the reverse rotation and in the constant speed rotation of the motor. CONSTITUTION:When the number of revolutions of a motor 1 is lower than the set number of revolutions due to a variable resistor 11 by a specified number of revolutions, an operational amplifier 21 becomes low-level while the output of an inverter 24 becomes high-level. An analogue switch 22 is thereby conducted while an analogue switch 23 is non-conducted. The amplification degree of an operational amplifier 13 is determined by resistances 14 and 15. When the speed of the motor 1 is increasing to approach the preset value, the output of the operational amplifier 21 gets high-level while the analogue switch 22 becomes non-conductive and the analogue switch 23 conductive. Under this circumstances, a negative feedback path by a resistance 16 and a capacitor 17 is formed. |
