| 摘要 |
PURPOSE:To simplify the structure of the speed controller for DC motor by a method wherein current conducting phase of a semiconductor means is controlled according to the comparison result between the deviation of counter-electromotive force of the motor from a speed setting voltage and a sawtooth voltage. CONSTITUTION:Rectifying diodes 20, 37 take out counter-electromotive force of the motor 4 to apply to a counter-electromotive force detecting resistor 40. A linear amplifier 50 outpus a speed instruction voltage Va according to counter- electromotive force detected by the detecting resistor 40 and the speed setting voltage Vs set by a variable resistor 46. When the sawtooth voltage synchronized with an AC electric power source 2 inputted from a terminal 70 reaches a voltage obtained by adding the speed instruction voltage Va and a correction voltage Vo, a comparator 66 outputs a square wave signal. The square wave signal is applied to the gates of the motor current conducting phase controlling thyristors 10, 12 through a pulse transformer 82. |
