Single phase asynchronous machine - has auxiliary phase capacitor connected to resonant circuit blocking current flow when machine is stationary

摘要

The auxiliary phase for starting and operation is in series with a capacitor. It is connected as a variable voltage source to an oscillating circuit. Its voltage is min. when the machine is stationary, and max. when running without load. Its inductive and capacitive reactances have a blocking effect at min. voltage, when a certain saturation of the inductor iron core is produced. It is due to the adjustment of the reactances causing the current from the auxiliary phase capacitor being nearly zero. At high speed, when iron core saturation is high and the resonance effect abruptly disappears, no more blocking effect is produced. The capacitor (4) can now discharge through the oscillating circuit (5, 6) or through its inductance, so that control of its charge permits the capacitor to retain its capacitive properties. It behaves like a capacitor during starting and normal operation.