Inverter controlled air conditioner capable of effectively reducing a rush current at starting

An inverter controlled air conditioner comprising:

• an inverter including a rectifying circuit having AC input terminals and DC output terminals, a smoothing capacitor connected to said DC output terminals of said rectifying circuit, and a switching circuit, connected to two terminals of said smoothing capacitor, for outputting a signal having a predetermined frequency which is capable of being changed in accordance with a control signal;
• a compressor motor driven by the signal having the predetermined frequency which is output from said switching circuit;
• an electromagnetic contactor having normally-open contactor contacts connected between said AC input terminals of said rectifying circuit and an AC power supply, and an electromagnetic contactor body for energizing to close said contactor contacts in accordance with a drive signal;
• an air conditioner body having a compressor driven by said compressor motor, a refrigerating cycle for circulating a refrigerant between outdoor and indoor heat exchangers by said compressor, and an indoor unit control section for outputting an operation command of said refrigerating cycle;
• an outdoor unit control section having an auxiliary power supply circuit, connected to said AC power supply, for obtaining a plurality of DC operation voltages, first and second relay drive circuits to which said plurality of DC operation voltages are applied from said auxiliary power supply circuit, and an inverter control circuit, said inverter control circuit having control means for supplying the control signal to said inverter in response to an operation command from said indoor unit control section and controlling said first and second relay drive circuits to operate at predetermined timings, and said first relay drive circuit being connected to said electromagnetic contactor body to provide the drive signal when said air conditioner is started;
• and
• rush current preventing relay means having at least one normally-open contact connected between said two terminals of said smoothing capacitor of said inverter and a predetermined output terminal of said auxiliary power supply circuit, and a relay body for energizing to close said normally-open contact in accordance with a drive signal from said second relay drive circuit, wherein
• said control means of said inverter control circuit enables said second relay drive circuit upon reception of a start command from said indoor unit control section and thereafter enables said first relay drive circuit, so that said smoothing capacitor of said inverter is charged in advance by an operation voltage from said auxiliary power supply circuit and thereafter an AC power supply voltage from said AC power supply is applied to said inverter, thereby preventing a rush current from flowing to said smoothing capacitor when said inverter controlled air conditioner is started.