| 摘要 |
PURPOSE:To take out a signal for determining the number of revolution, by connecting the rotor of a commutator-type motor via an impedance or a reactance element to a power source and detecting the variation in a current flowing through the rotor thereby. CONSTITUTION:A rotor of a DC super-mini-motor is connected in series with an impedance or a reactance element 8 across power source 7, and the variation in a current flowing through the impedance or reactance element 8 is detected for taking out a variation-signal 9. Since the variation in the impedance viewed from the power source 7 caused by the switching of brush contacting with the commutator as the rotor 6 retates produces a variation in the current to be taken out, a signal indicative of the number of revolution of the motor can be obtained without providing a particular detecting device. |
