| 摘要 |
PURPOSE:To heat the compressor itself from the inside thereof so that the inside temperature of the compressor is prevented from lowering less than a predetermined value, by generating a high voltage having a frequency higher than the ordinary operation frequency by power converting means at the low- temperature time. CONSTITUTION:An operation instructing device 23 outputs a target operation rotational speed signal, and an inverter drive signal generator 21 outputs a base drive signal to transistors 2-7 via driver circuits 15-20, and a three-phase AC voltage is applied to between respective terminals of a stator winding 14 to operate the compressor at a predetermined rotational speed. While the compressor is in stop, when the atmospheric temperature is lowered, it is detected by a temperature detector 23, a stand-by operation instruction is outputted from the operation instructing device 22, and an inverter drive signal device 21 outputs a base drive signal to transistors 2-7 via driver circuits 15-20, and an AC voltage is applied between respective terminals of the stator winding 14. As the frequency upon this occasion is used a single-phase AC wave of a frequency of approximately 25 kHz which is higher than the ordinary operation frequency. |
