Patents by Inventor Stephen Paul McDonald

Stephen Paul McDonald 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).

  • Electric motor starting circuit
    Patent number: 5969497
    Abstract: An electric induction motor can be given a kick start without excessive current drain on the supply by first connecting a unidirectional supply to a winding of the motor to build up a stationary rotor flux and then applying a starting current to another winding of the motor to produce a stator flux at an appropriate angle (between 0.degree. and 180.degree.) with the stationary rotor flux. Once the motor has begun accelerating the normal running supply can be connected. This starting current may be derived from a capacitance which is charged up during the period of establishing the stationary rotor flux.
    Type: Grant
    Filed: November 25, 1998
    Date of Patent: October 19, 1999
    Assignee: EA Technology Limited
    Inventors: Stephen Paul McDonald, Geoffrey David Baines, John Talbot Boys