| 摘要 |
PURPOSE:To eliminate the application of a shock to a load when shifting to full voltage by gradually increasing to the full voltage after holding at the reduced voltage adapted for slowly starting the voltage of a motor for the prescribed period. CONSTITUTION:A relay X is operated first, and contacts X1, X2 then open. Thus, the voltage of the output terminal A of an operational amplifier OP3 is applied as a start signal to a firing circuit 3, and a motor M is slowly started in a suitable firing phase. Simultaneously, the first condenser C1 which forms a timer circuit T starts charging at the time constant set by a variable resistor VR2. The voltage of the output terminal B of an operational amplifier OP4 decreases when becoming e1>e2, and the voltage of the output terminal C of an operational amplifier OP5 similarly varies. In this manner, the voltage at C operates to gradually accelerate the firing phase instead of the voltage at A to raise the motor voltage, thereby gradually accelerating the motor M. |
