Allen-bradley Company, LLC

Jinghan Tao

Peter J Unsworth

John C Merrison

A method and apparatus to be used with an inverter based motor controller for determining current phase angles for the current on a single phase of a three phase AC motor from an inverter generated high frequency phase voltage sequence. The invention detects turn on delay periods and compares phase voltages during consecutive turn on delay periods to determine phase current zero crossing times which can be used along with phase voltage zero crossing times to derive current phase angle information.

Method and apparatus for detecting current delay angle from motor

A method and/or apparatus used with a voltage/frequency driver for controlling a motor that maintains a motor driving magnetizing flux at low frequencies and maintains a constant desired motor speed despite relatively high slip at low frequencies. The voltage/frequency driver controls both magnetizing flux and motor speed without requiring sensing or calculating hardware in addition to hardware typically included with a voltage/frequency driver.

Auto boost for voltage/frequency motor controller

A method and apparatus used with a motor controller that detects load imbalance at a relatively low speed and, if the degree of load imbalance is greater than a predetermined acceptable maximum degree, produces an alarm signal that indicates an imbalanced load. If the degree of load imbalance is greater than the predetermined acceptable maximum value, the present invention may either attempt to rebalance the load or stops the motor until the balance can be manually adjusted.

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Shorewood, WI, United States of America

Jinghan Tao