Patents by Inventor Michael H. Lafferty

Michael H. Lafferty 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).

  • Thermal protection for AC traction motors using temperature estimations to calculate torque limits and blower speed requirements
    Patent number: 5446362
    Abstract: A thermal protection apparatus for an AC traction motor including a stator, a rotor, a blower fan, and an inverter includes measuring apparatus for measuring ambient air temperature of the motor and atmospheric air pressure of the motor. A computer is provided for using the measured ambient air temperature and atmospheric air pressure values for estimating a plurality of temperatures in the AC traction motor and for calculating a plurality of motor torque limits imposed by the plurality of estimated temperatures. A control system is provided for controlling the inverter by providing a signal comprising the lowest of the calculated plurality of motor torque limits to an inverter controller. The control system can also be used to calculate a plurality of blower speed requirements imposed by the plurality of estimated temperatures and set the blower speed of the motor to the highest of the calculated plurality of blower speed requirements.
    Type: Grant
    Filed: June 21, 1994
    Date of Patent: August 29, 1995
    Assignee: General Electric Company
    Inventors: Laurence D. Vanek, Robert G. McGrath, Michael H. Lafferty