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Device and method for load control to control the speed of an AC motor to be directed to a supply voltage AC from a power source and method for changing the speed of an AC motor control device in a load
Device and method for load control to control the speed of an AC motor to be directed to a supply voltage AC from a power source and method for changing the speed of an AC motor control device in a load
Device and method for load control to control the speed of an AC motor to be directed to a supply voltage AC from a power source and method for changing the speed of an AC motor in a device for load control.The controller of speed of an AC motor including a plurality of capacitors that may be selectively connected through switches conductive controlled in electrical connection in serial with an AC motor and a source of AC voltage to control the speed of the engine.To change the speed of the motor, a control circuit has a first switch conductive, in response to a first intercept of zero voltage AC detected, to load a first capacitor to a predetermined voltage.The control circuit then provides a second switch conductive, in response to a second subsequ00faente intercept of zero AC voltage detected, to load a second capacitor to a predetermined voltage.The control circuit then presents both switches simultaneously conductive to a predetermined time after a third subsequent third intercept of zero AC voltage detected. The capacitors that are charged to the same voltage before being connected in serial with the engine, thereby resulting in reduced acoustic noise when the engine speed is changed.
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