Magnetek, Inc.

Phillip G Langhorst

An electrostatic shielding system is provided for an AC motor to eliminate generation of destructive motor bearing currents. Conductive end turn shields are layered over the stator coil end turns at each end of the stator. Conductive grounding clips mechanically and electrically engage the end turn shields at one end of the clip, and electrically and mechanically engage the slotted openings in the stator at the other end. Conductive strips extend longitudinally along the stator slotted openings.

Electrostatic shielding system for reduction of bearing currents in

A drive circuit for a switched reluctance motor has phase circuits connected to a common dump capacitor which receives residual magnetic energy from each phase coil when it is switched off. One or more recovering phase circuits are connected to the dump capacitor and comprise a controlled switch and diode whereby energy stored in the dump capacitor is returned to a recovering phase coil in sequence.

Drive circuit for a switched reluctance motor with improved energy

The present invention provides a sensorless circuit for detecting rotational speed of a rotor in an induction motor. The circuit includes a switch between the AC source driving the motor and a motor phase winding. When the switch is closed, there is developed across the phase winding a voltage waveform from the AC source. When the switch is subsequently opened, there is developed across the winding a residual voltage waveform induced by the rotor. The speed of the motor is determined by measuring a time interval between selected points on the voltage waveform.

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Crestwood, MO, United States of America

Phillip G Langhorst