| 摘要 |
PURPOSE:To reduce a current at the switching time by driving an inverter in response to the phase of a power source voltage when switching from a commercial power source to a drive inverter. CONSTITUTION:A commercial power source 8 is switched to a motor drive inverter 2 by inputting a switching signal 10 to a controller, first turning OFF a triac 5, and switching a switching relay 4 to an inverter side. Then, a signal is applied to an inverter power transistor 3 at the timing synchronized with the power source voltage phase detected by a power source voltage detector 7 to drive a single-phase induction motor 1 for a compressor. When the inverter drive is executed at the timing synchronized with the power source voltage phase, the inverter is driven at the position where the apparent slip of the motor is small, thereby reducing the current flowed in the power transistor. |
