| 摘要 |
PURPOSE:To prevent a power circuit from increasing its size in an air conditioner which increases or decreases the number of compressors to be operated by providing an inverter circuit carrying out power supply to a plurality of compressors further providing control means for decreasing the output frequency and voltage of the inverter circuit upon starting respective compressors, and suppressing the starting currents of respective compressors. CONSTITUTION:When an operation starting instruction signal enters a control part 20, the control part 20 operates a relay 3, and a compressor motor 11 starts its operation to start a first compressor. In this case, since the output of the inverter circuit 2 assumes a low frequency and a low voltage, the starting current becomes forcibly small. When the starting of the first compressor is completed, the control part 20 increases the output frequency and voltage (V/F) of the mode operation due to the first compressor, the temperature within the compartments of the train is not lowered contrary to expectation, the control part 20 further operates a relay 4 and decreases the output frequency and voltage of the inverter circuit 2 to suppress the starting current to a sufficiently small value. When the starting of a second compressor is completed, the control part 20 increases the output frequency and voltage (V/F) of the inverter circuit 2. Thus, the first and second compressors enter a steady operation, and the cooling operation of the maximum capacity is performed. |
