| 摘要 |
PURPOSE:To reduce abnormal noise, by applying phase control onto every other Hertz of voltage to be applied onto a motor, thereby halving electromagnetic higher hermonic. CONSTITUTION:A triac 5 is connected between a power source 1 and a high speed strong tap 3 of a motor, while a triac 6 is connected between the power source 1 and a weak tap 4. A generator 9 is connected to the gate 7 of the triac 5 and to the gate 8 of the triac 6. The generator 9 outputs conduction, non-conduction and phase control in combination. Consequently, the voltage to be applied onto the motor is subjected to phase control for every other Hertz, and thereby the level of higher hermonic of source is halved, resulting in reduction of abnormal noise. |
