| 摘要 |
PURPOSE:To perform a quick and sure electric discharge of a smoothing capacitor adapted for stopping of a compressor by open-phase operating a motor at the time of stopping the operation of said compessor. CONSTITUTION:At the time of stopping the operation of a compressor 1, an opening command is always given to one of switching elements S1, S2, S3 to switch a one-phase power line to an open-phase one and a make and break command is also given continuously to a switching element for another power line for open-phase operation of a motor 4. Consequently, the charged electricity of a smoothing capacitor C can disappear via a discharge circuit formed between not open-phasic power lines. Moreover, a rotating magnetic field can also be prevented from generating in said motor 4 so that a sudden rotation of the motor 4 is eliminated. |
