| 摘要 |
PURPOSE:To prevent a compressor from being locked at the time when operation frequency of a capability-varying control type air conditioner is being lowered. CONSTITUTION:An AC power source of a power supply 1 is converted to a DC power supply in a rectifying/smoothing circuit 4 and is converted into an AC power supply of a predetermined frequency in an inverter circuit 5 to drive a compressor 6. A microcomputer 8 outputs a frequency control signal to the inverter circuit 5 on the basis of a control signal, etc., inputted from an input machine 2 through a communication circuit 9. Upon the operation frequency of the compressor 6 being lowered, an input current to the rectifying/smoothing circuit 4 is detected by an input current detection circuit. When a detected value increases beyond a predetermined value and the state continues for a predetermined time, the microcomputer 8 increases the operation frequency of the compressor 6 to avoid the locking of the compressor 6 and thereafter the operation frequency is again lowered. |
