| 摘要 |
PURPOSE:To enable a motor to be effectively cooled, by finding the field current and the field voltage of the cooled motor to compute field winding resistance and to find the present temperature of the motor, and by grasping the change of temperature to control the air quantity of a cooling fan. CONSTITUTION:The current If and the voltage Vf of the field windings of a cooled motor 8 are detected by detectors 1, 2, and the temperature of the cooled motor 8 is performed arithmetic 3, and the input to a subtracter 5 is provided. By the subtracter 5, detected present temperature and temperature set at a temperature setting device 4 are subtracted 5, and deviation is found, and the input to a cooling motor speed reference correction device 6 is provided, and the deviation content is differentiation-detected, and when the differential coefficient is constant or more, then during the period, the output of a constant correction quantity against the speed reference applied to the cooled motor 8 is directed to a cooled-motor driving gear 7. As the result, a temperature sensor is not needed, and the device copes with sudden temperature rise effectively, and a set temperature is always kept, and energy-saving effect is obtained.
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