| 摘要 |
PURPOSE:To reduce the Joule loss in a transistor by switching the transistor under the control of electric power supplied to a motor. CONSTITUTION:When the voltage of a condenser 4 is raised over an upside set value, a transistor 14 is turned ON, while a transistor 15 is turned OFF, and a transistor 2 is turned OFF, and magnetic energy stored in the coil 3 is discharged through a flywheel diode 5. When the voltage of the condenser 4 is lowered below the lowerside set value, the transistor 14 is set OFF, the transistor 15 is set ON, and the transistor 2 is set ON. On the other hand, when the rotating speed of a motor 6 is varied, the collector current of the transistor 10 is varied, thereby varying the upper and lower set values and controlling the rotating speed. In this manner, the Joule heat of the transistor can be reduced. |
