| 摘要 |
PROBLEM TO BE SOLVED: To reduce the volume of an inverter in a freezer which controls the revolution speed of a compressor using the inverter while sufficiently maintaining the starting torque of the compressor. SOLUTION: In a method of starting a compressor in a freezer, commercial electric power is directly supplied to an induction motor 10, without passing through an inverter 8 during the starting period of the compressor 1, and a desired electric power is supplied to the induction motor 10 via the inverter 8 except at the start period. First, the commercial electric power is supplied directly to the induction motor 10 to start the compressor, and thereafter the commercial power supply is switched to the inverter power supply, on the condition that the suction pressure of the compressor 1 become lower than a prescribed pressure and the motor current becomes less than a prescribed value.
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