Patents by Inventor Thomas A. Lemak

Thomas A. Lemak 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: 7219673
    Abstract: The cascaded, multi-level inverter can be found in a variety of applications and in a variety of industries. The inverter is typically used as a motor drive to provide variable voltage and variable frequency to a propulsion motor or other loads requiring variable frequency and voltage. In the present invention, the transformer is eliminated and its function included in an existing generator by adding a plurality of secondary windings to supply the isolated voltages needed by the multi-level power converter. Two specific examples of the present invention include a cascaded, multi-level inverter, or a variant referred to as the multi-source, flying source inverter, whose ac input voltage is derived from an electromagnetic generatorator.
    Type: Grant
    Filed: August 25, 2004
    Date of Patent: May 22, 2007
    Assignee: Curtiss-Wright Electro-Mechanical Corporation
    Inventor: Thomas A. Lemak
  • Patent number: 7019421
    Abstract: A linear motor system including compartmentalized stator sections provides an interchangeable and serviceable alternative to other linear motors. The stator sections may be individually-energized so that power is only sent to stator sections adjacent to the thrust plate or rotor of the linear motor. A sufficiently long thrust plate is used to cover any gaps in the linear stator, and additional compensation stator sections are used to provide additional motor force to the thrust plate adjacent to these gap sections. If utilized onboard a ship, additional compensation stator sections may be incorporated into the face of deck hatches. The linear motor system can also be used to counteract gravitational effects in a large hanging door system implementation.
    Type: Grant
    Filed: February 20, 2004
    Date of Patent: March 28, 2006
    Assignee: Curtiss-Wright Electro-Mechanical Corporation
    Inventors: David J. Hall, Thomas A. Lemak, Regis J. Hillenbrand
  • Publication number: 20060044857
    Abstract: The cascaded, multi-level inverter can be found in a variety of applications and in a variety of industries. The inverter is typically used as a motor drive to provide variable voltage and variable frequency to a propulsion motor or other loads requiring variable frequency and voltage. In the present invention, the transformer is eliminated and its function included in an existing generator by adding a plurality of secondary windings to supply the isolated voltages needed by the multi-level power converter. Two specific examples of the present invention include a cascaded, multi-level inverter, or a variant referred to as the multi-source, flying source inverter, whose ac input voltage is derived from an electromagnetic generatorator.
    Type: Application
    Filed: August 25, 2004
    Publication date: March 2, 2006
    Inventor: Thomas Lemak
  • Patent number: 4851949
    Abstract: In an active shaft ground system for maintaining a rotating shaft (4) of a machine substantially at ground potential, which system includes a circuit coupled to the shaft (4) for monitoring the voltage on the shaft (4) relative to ground and a brush (6) coupled to the circuit and contacting the shaft (4) for conducting to the shaft (4) a compensating current having an amplitude and polarity adjusted for maintaining the shaft voltage substantially at ground potential, there is provided shaft condition detection circuitry (18,20,24,26,28,34,36) coupled to the circuit for monitoring the voltage on the shaft (4) relative to ground and the current flowing between the brush (6) and the shaft (4) and for producing a fault indication when the voltage on the shaft (4) relative to ground is outside of a selected range at the same time that the current flowing through the brush (6) is substantially equal to zero.
    Type: Grant
    Filed: June 13, 1988
    Date of Patent: July 25, 1989
    Assignee: Westinghouse Electric Corp.
    Inventors: Thomas A. Lemak, Robert L. Osborne, Michael Twerdochlib