| 摘要 |
PURPOSE:To detect exact voltage by arranging a plurality of switch circuits, a first detecting means for detecting voltage, a second detecting means for detecting both the end voltage of a resistor, and the like, and by detecting voltage to be applied to exciting windings, directly. CONSTITUTION:Switch circuits with a plurality of switching elements 10-12, a first detecting means 13 for detecting driving voltage to be applied to respective exciting windings, via the respective switch circuits, a resistor 5 for current flowing to the respective windings, a second detecting means 14 for detecting a voltage across the resistor 5, and the like are arranged. Each input of detected results duet to the first and second detecting means 13, 14 is provided, and the output of the voltage E of an equation is generated, and the output of the voltage E is contrived to be generated as the detected output of the rotational speed of a rotor. In the equation, by V, the driving voltage detected by the detecting means 13 is shown, and by VR, voltage-across-resistor detected by the second detecting means 14 is shown, and by Ro, the resistance value of the internal resistance of the respective windings is shonw, and by Rf, the resistance value of the resistor 5 is shown. As a result, voltage to be applied to the exciting windings of a motor can exactly be detected. |
