| 摘要 |
PURPOSE:To improve the reliability and the safety by operating a switching circuit by a power interruption signal generated from a no voltage detector due to a power interruption, and interrupting a driver and a control signal line. CONSTITUTION:A main circuit DC power source 1 and a controller DC power source 2 are provided individually at commercial AC power source, and a DC power is converted by a transistor module (inverter) 3 into an AC power source. The power transistors of the module 3 are driven to be oscillated by the frequency corresponding to a control signal by a driver 4 to stepwisely control the capacity of a compressor 8 of an air conditioner. In this case, a no voltage detector 6 for detecting the no voltage of the input terminal of the power source 1 and a switching circuit 7 for interrupting the control signal line when a power interruption signal is output. Thus, the communication of the control signal line to the driver 4 is rapidly interrupted by the circuit 7 at power interruption time to fully protect the module 3. |
