Unico Corp.

James J Sewell

William S Hammel

Harry W Schulz

Michael O Lucas

Rick L Tennessen

A method of operating an electric induction motor with a variable-speed drive includes determining a voltage level on a DC bus for the drive, and measuring a first magnitude of magnetic flux from a stator of the normally-operating electric motor, determining a normal flux level. The method includes disabling a first output to the drive when the DC bus voltage is less than a first threshold level. The method includes measuring a magnetic flux feedback signal having a phase and second magnitude, estimating a speed of the electric motor, and configuring a second output signal for the drive when the DC bus voltage is greater than a second threshold level. The second output signal matches a signal from the second magnitude and a phase of magnetic flux. The method includes enabling the drive output to restart the electric motor when the magnetic flux is greater than a third threshold value.

Power-loss ridethrough system and method

An apparatus is provided for controlling operation of an electric motor through use of an additional power storage arrangement connected across the DC busses of a motor drive and controlling the speed of the motor. The additional power storage arrangement includes an additional capacitor arrangement and a rate limiting arrangement in a series circuit relationship with one another.

Growing community of inventors

Racine, WI, United States of America

James J Sewell