| 摘要 |
PURPOSE:To permit the avoidance of the loss of the whole of a system by a simple constitution by a method wherein a load is driven by a commercial power source circuit while bypassing an inverter when an external control signal is a high load signal while the circuit of the side of a load is intercepted when the external control signal is a low load signal. CONSTITUTION:The required load of a load 2 is selected to divide it into a high load area, higher than 80%, a medium load area, lower than 80%, and a low load area, lower than 30%. When the external control signal of a medium load area is inputted, operation is effected through an inverter circuit and when the external control signal of the high load area is inputted, the operation is effected through a commercial power source circuit. The attenuating time t2 of a remaining voltage is secured upon switching from the inverter circuit operation into the commercial power source circuit operation while a time t3, requested until the rotating speed of a motor is synchronism with a speed proportional to the requested signal of the inverter circuit, is secured upon switching from the commercial power source circuit operation into the inverter circuit operation. |
