Power Control For Induction Motors Using Variable Frequency AC Power
AssigneeThe Boeing Company
InventorsRobert E. Fisher, John T. Paterson
Life of this patent
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Abstract
An autonomous controller allows an AC induction motor to operate over a broad range of AC power supply frequencies by reducing the amount of current supplied to the motor at lower frequencies. The controller detects the frequency of the power supply and switches the supply current on and off during each AC cycle to limit the RMS current to a value that is related to the detected frequency. Alternatively, the controller switches capacitive reactance into the power supply circuit which reduces the current supplied to the motor at lower AC frequencies.
Claims13
1-7. (canceled)
(canceled)
9-12. (canceled)
(canceled)
A method of controlling power supplied by an AC power source to an induction motor over a range of frequencies, comprising the steps of:
- (A) detecting the frequency of the AC power being supplied to the motor;
- and,
- (B) reducing the current supplied by the AC power source to the motor based on the frequency detected in step (A).
A method of controlling power supplied by an AC power source to an induction motor over a range of frequencies, comprising the step of
- (A) introducing reactive capacitance between the AC power source and the motor to limit the current supplied to the motor from the AC power source at lower frequencies in the range of frequencies
Dependencies are inferred from the claim text.