Patents by Inventor Laurence M. Wright

Laurence M. Wright has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5198733
    Abstract: A brushless DC motor is started by initially specifying an arbitrary rotor position and applying such drive currents to the three motor phase inputs that the rotor moves to the predetermined position and thereafter applying a current pulse to the appropriate winding to cause the rotor to move in the desired rotational direction. After the motor has begun to turn, the current supply to the motor phase inputs is interrupted. The current in the motor is allowed to decay to a level where the I and R voltage drops in the windings are substantially less than the back EMFs at the speed at which the motor is turning. The small back EMFs generated in the windings are sampled and monitored to detect whether the rotor has moved to a position requiring a change in commutation. Drive current is supplied to the three motor phase inputs in accordance with whether or not a need for a change in commutation was detected by the sample so that the rotor will continue to turn in the required direction.
    Type: Grant
    Filed: November 13, 1990
    Date of Patent: March 30, 1993
    Assignee: International Business Machines Corporation
    Inventor: Laurence M. Wright