| 摘要 |
PURPOSE:To prevent a motor against finer rotational unevenness, by effecting minute changes to the frequency and phase of supply voltage (or input signal) which energizes electrostrictive elements of a vibrating substance in alternate current. CONSTITUTION:A speed control circuit of an oscillating wage motor equipped with electrostrictive elements 1a-1c is composed of a control arithmetic unit 8, a frequency detector 9, a rotating speed detector 10, a variable voltage generator 11, a variable frequency generator 12 and a phase difference generator 13 and energizes in AC above-mentioned driving electrostrictive elements 1a and 1b through power amplifier 14-15. The control arithmetic unit 8 thereby finds the difference between the signal detected by the rotating speed detector 9 and the target rotating speed. On the basis of its signal a voltage command signal 8a is given to a variable voltage signal generator 11 to change the supply voltage. The command signal 8a is caused to change minutely in accordance with the speed deviation. The feedback control is thereby performed and the rotating speed is controlled as constant. |
