| 摘要 |
Blanking interval circuitry (106, 108, 110, 104) is disclosed for preventing immediate connection of the start capacitor (5) of an AC motor to the AC source (4) upon energization of the motor, to protect the motor against an overcurrent condition if the motor is de-energized while in the running mode and then re-energized while still coasting above a given speed, and to particularly prevent burn out of the start capacitor (5) and/or start switch (10) upon reapplication of electrical power after a momentary power outage. The start capacitor (5) is disconnected from the AC source (4) during a time delay blanking interval regardless of whether auxiliary winding voltage is above or below a given cut-in value relative to main winding voltage as a function of motor speed corresponding to a given cut-in speed. After the time delay blanking interval, a cut-in comparator (86) actuates start switch circuitry (54, 10) to connect the start capacitor (5) through the auxiliary winding (2) to the AC source (4) only if auxiliary winding voltage has dropped to or below the cut-in value.
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