| 摘要 |
PURPOSE:To improve the energy conversion efficiency in accordance with a high load by feeding power to a compressor driving moor through a frequency converter which is a variable frequency power source and generates a frequency which is higher than that of a commercial power source, when the load of the freezer is large. CONSTITUTION:During the space heating operation wherein the load of the freezer is large, changeover switches 14 and 15 are switched and a compressor driving motor 19 is inverter-driven. At the same time, a switch 16 for a four-way valve is turned ON and power is supplied to a four-way valve 18. Thus, an inverter starting switch 17 is turned ON and a power source voltage is applied to a power source frequency detection circuit 13. This detection circuit 13 detects the frequency detection circuit 13. This detection circuit 13 detects the frequency of the power source voltage and pulsates the same, and transmits a signal to a control signal circuit 12. This signal circuit sets the transmission and the frequency of the inverter to values in accordance with the magnitude of the freezing load in every 50Hz area and 60Hz area to start the compressor driving motor 19.
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