| 摘要 |
PURPOSE:To decrease an unnecessary power loss by igniting a first bidirectional thyristor once during a semiperiod of a commercial power source, and thereafter, igniting a second bidirectional thyristor. CONSTITUTION:A main body contains a motor-driven air blower 3 connected in series to a commercial power source 2, a first bidirectional thyristor 4, a resistor 5, a second bidirectional thyristor 6 connected in parallel to the thyristor 4 and the resistor 5, and a control circuit block 7 for applying an ignition signal to gates of the thyristors 4, 6. In such a state, in the case of controlling an input and an output of the motor-driven air blower 3 by using a phase control system, a first bidirectional thyristor 4 is ignited once during a semiperiod of the commercial power source 2, and thereafter, a second bidirectional thyristor 6 is ignited. According to this constitution, before the motor-driven air blower 3 conducts by phase control, it becomes a conducting state once in a state passing through the resistor 5, therefore, a rush current is suppressed, and since a rise of a current waveform becomes dull, generation of a high frequency current can be decreased. |
