| 摘要 |
PURPOSE:To always generate a suitably driving torque irrespective of change of environmental temperature by providing a resistance element varying according to the ambient temperature between a power source of a motor and a coil, and providing a variable resistance element in series with a diode for feeding back a current generated by a counterelectromotive force generated at the coil. CONSTITUTION:When a current limiting resistor is replaced with posistors P1-P5, if the ambient temperature is high, the resistance value of the posistor P5 becomes high, currents iF1-iF4 are reduced, and heat generation is suppressed. Since the resistance values of the posistors P1-P4 also become high, the values of circulating currents iR1-iR4 are suppressed. If the ambient temperature is low, the resistance value of the posistor P5 becomes low, the currents iF1-iF4 are increased to increase its torque. Since the resistance values of the posistors P1-P4 also become low, the values of circulating currents iR1-iR4 are also increased. |
