Thor Technology Corporation

Square D Company

A.o. Smith Corporation

Jerome J Reichard

Joseph R Pottebaum

Karl M Hink

John G Reichard

Douglas B Weber

Theodore O Wiesendanger

Bruce C Wagner

Jeffrey J Cybela

In a plural phase electric motor, a control method senses regeneration current from a non-energized phase and commutates to the next state. In the next state, the unenergized phase of the present state is energized in a polarity opposing the regeneration current of the present state, such that during the next state, energization current is directed in the last noted phase in a direction opposite to the regeneration current of the present state. In the state prior to the present state, the unenergized phase of the present state is energized in a polarity aiding the regeneration current of the present state, such that during the prior state, energization current is directed in the last noted phase in the same direction as the regeneration current of the present state. In the preferred embodiment, all of the commutation switches are periodically simultaneously turned off for a given blanking interval, and the regeneration current is sensed on a common DC bus during such interval.

Electric motor with regeneration current commutation

In a plural phase electric motor, a control system provides a variable commutation delay interval between commutations from state to state, during which delay interval all phases are unenergized, to minimize current spikes upon commutation. The duration of the delay interval is varied according to a given motor operating parameter during operation of the motor to optimize the delay interval for different operating conditions, to provide maximum delay when needed to eliminate current spikes, and to provide minimum delay when unneeded, to in turn provide maximum energization current to the phases. In one embodiment, motor speed is sensed, and the duration of the delay interval is varied in response thereto by shortening the delay interval with increasing motor speed. In another embodiment, DC bus current is sensed, and the duration of the delay interval is varied in response thereto by preventing termination of the delay interval until the level of DC bus current drops below a given value.

Electric motor with variable commutation delay

A variable speed eddy current electric motor includes a zero-torque regulating circuit that senses and responds to the current flowing through an eddy current motor field coil. As the magnitude of the field coil's current is changed by the eddy current motor's speed control circuit, the operating method of the zero-torque regulating circuit supplies varying amounts of current to flow through the field coil in a direction opposite to that of the current applied thereto by the speed control circuit. Thus, when the eddy current motor's speed control circuit no longer causes any current to flow through the field coil, the current supplied to the field coil by the zero-torque regulating circuit produces a magnetic filed that removes all torque from the eddy current motor's output shaft.

Zero-torque eddy current motor system and method for controlling same

A switching network on a volatile memory circuit card assembly includes a back-up battery power supply to supply power to the volatile memory components upon failure of a line source of electrical power. A high capacitance capacitor acts as a power source to supply power to the memory components upon failure of the line source of power and before tha back-up battery power supply acts. This substantially increases the life of the battery. The switching network also provides a switch normally conducting the line source electrical power to the memory components and that isolates the memory components from the line source electrical power supply upon a failure. Switches also isolate a WRITE signal form the memory components and produce a PROTECT signal with a hysteresis effect. A second battery located off the card assembly can act to supply power before the first battery on the card assembly.

Growing community of inventors

Menomonee Falls, WI, United States of America

Jerome J Reichard