| 摘要 |
<p>A method for controlling turn-on/off of a motor preheating device, wherein a motor (4) is preheated with a high electric power efficiency by generating heat by hysteresis loss and by resistance loss by periodically reversing the direction of the electric current flowing through the stator coils (6a, 6b, and 6c) of the motor (4). The method comprises turning on/off a first transistor (10) in a prescribed cycle for a prescribed time T1, keeping on fifth and sixth transistors (14, 15) during the prescribed time T1, stopping the driving of the transistors (14, 15) for a prescribed time T2, thereafter, for a prescribed time T3, turning on/off a fourth transistor (13) in a prescribed cycle and keeping on second and third transistors (11, 12) then, stopping the driving of the transistors (11, 12) for a prescribed time T4, and repeating the steps.</p> |
