| 摘要 |
<p>PURPOSE:To obtain a counter electromotive force detection means of a simple constitution at low cost, by a method wherein a rectifying element is made to lie between a voltage phase control means of a power source and a DC motor and, in case the voltage signal on the side of the power source side is zero, the voltage signal on the DC motor is detected as a counter electromtive force. CONSTITUTION:A rectifying element D is made to lie between a voltage phase control means 3 and a DC motor 2 to detect the voltage between both ends a and b of said rectifying element D through a detection means 11. And in case there is a differenct between the electric signal at the point a and that at the point b, the voltage at the point a as an induction electromotive force signal d is compared with the output signal of a speed setter 8 to feed the deviation signal thereof in a phase control circuit 10 through an amplifier 9.</p> |
