Patents by Inventor Thomas Keister

Thomas Keister 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).

  • Publication number: 20100328848
    Abstract: In one embodiment, a medium voltage drive system includes at least one transformer and multiple power cell chambers each coupled to a transformer. The power cell chambers each may include a rectifier, a DC-link, and an inverter. Each power cell chamber can be separated into fixed and moveable portions, where the moveable portion includes the rectifier and the inverter and the fixed portion includes the DC-link. A power service bus can couple the fixed and moveable portions of each power cell chamber and couple in series groups of the plurality of power cell chambers.
    Type: Application
    Filed: June 30, 2009
    Publication date: December 30, 2010
    Inventors: Enrique Ledezma, Thomas Keister, Mehdi Abolhassani, Ryan Edwards, Alex Skorcz, Randall Pipho, Srinivas Satumahanti
  • Patent number: 7830681
    Abstract: In one embodiment, the present invention includes a system having multiple modular transformers each including a phase-shifted primary winding coupled to an input power source and phase-shifted secondary windings each coupled to a power cell. The system further includes different phase output lines coupled to a load. These lines may include first, second and third phase output lines.
    Type: Grant
    Filed: September 24, 2008
    Date of Patent: November 9, 2010
    Assignee: TECO-Westinghouse Motor Company
    Inventors: Mehdi Abolhassani, Ryan Edwards, Thomas Keister, Alex Skorcz, Enrique Ledezma, Chao Hsu Liao
  • Publication number: 20100213921
    Abstract: A transformer module includes a main primary winding coupled to a first input power source to receive a medium voltage signal, multiple main secondary windings each to couple to a power cell of a drive system, and an auxiliary primary winding coupled to a second input power source to receive a low voltage signal. The auxiliary primary winding can be spatially separated from the main windings to increase leakage inductance. The auxiliary primary winding can be active during a pre-charge operation to pre-charge the power cells.
    Type: Application
    Filed: February 26, 2009
    Publication date: August 26, 2010
    Inventors: Mehdi Abolhassani, Thomas Keister, Alex Skorcz, Ryan Edwards, Enrique Ledezma
  • Publication number: 20100142234
    Abstract: In one embodiment, the present invention includes a medium voltage drive system having multiple power cells each to couple between a transformer and a load. A first subset of the power cells are configured to provide power to the load and to perform partial regeneration from the load, and a second subset of the power cells are configured to provide power to the load but not perform partial regeneration. A controller may be included in the system to simultaneously control a DC bus voltage of at least one of the first subset of the power cells, correct a power factor of the system, and provide harmonic current compensation for the system.
    Type: Application
    Filed: December 31, 2008
    Publication date: June 10, 2010
    Inventors: Mehdi Abolhassani, Thomas Keister, Alex Skorcz, Enrique Ledezma, Ryan Edwards
  • Publication number: 20100133816
    Abstract: In one embodiment, the present invention includes a turbine to generate mechanical energy from kinetic energy, a generator coupled to the turbine to receive the mechanical energy and to output multiple isolated supply powers, and multiple power stages each coupled to the generator. Each of the power stages may receive at least one of the isolated supply powers.
    Type: Application
    Filed: June 30, 2009
    Publication date: June 3, 2010
    Inventors: Mehdi Abolhassani, Thomas Keister, Haran Karmaker, Ryan Edwards, Enrique Ledezma, Alex Skorcz
  • Publication number: 20100072824
    Abstract: In one embodiment, the present invention includes a system having multiple modular transformers each including a phase-shifted primary winding coupled to an input power source and phase-shifted secondary windings each coupled to a power cell. The system further includes different phase output lines coupled to a load. These lines may include first, second and third phase output lines.
    Type: Application
    Filed: September 24, 2008
    Publication date: March 25, 2010
    Inventors: Mehdi Abolhassani, Ryan Edwards, Thomas Keister, Alex Skorcz, Enrique Ledezma, Chao Hsu Liao
  • Publication number: 20100073970
    Abstract: In one embodiment, a system may include multiple transformers each to provide an output to one or more power cells, where the power cells provide AC power to a load. Each transformer may have at least one primary winding and multiple secondary windings, where the primary winding of each transformer is phase shifted with respect to its neighboring transformers and the secondary windings are also phase shifted. The phase shift of the primary winding can be based on the phase shift of the secondary windings and a number of the plurality of transformers.
    Type: Application
    Filed: September 24, 2008
    Publication date: March 25, 2010
    Inventors: Mehdi Abolhassani, Ryan Edwards, Thomas Keister, Alex Skorcz, Enrique Ledezma, Chao Hsu Liao
  • Patent number: 7191074
    Abstract: An electric power monitoring and response system using electromagnetic field sensors located remotely beside the phase conductors. The system determines unknown system variables for one or more three-phase power lines based on measured values obtained form the field sensors and, in some cases, known power system values. For a given physical configuration, the field sensors may include a magnetic or electric field sensors, and the known system values as well as the unknown system variables may include phase currents, phase voltages and distances defining the physical configuration of the system. The response equipment may be a display, a circuit interrupting device, a voltage regulator, a voltage sag supporter, a capacitor bank, communication equipment, and reporting system.
    Type: Grant
    Filed: May 18, 2005
    Date of Patent: March 13, 2007
    Assignee: SSI Power, LLC
    Inventors: Joseph R. Rostron, Raj Anand, Lyle Thomas Keister
  • Patent number: 6041850
    Abstract: A system for temperature control of an electronic component includes a heat plate supporting the component; a heat plate temperature sensor; a fan capable of providing air for cooling the heat plate; and a fan control for using the heat plate temperature to control the operation of the fan to provide a substantially constant heat plate temperature. The system can further include a heat pipe assembly having fins and coupled to the heat plate with the fan capable of providing air to the fins. The heat pipe assembly can include at least two heat pipes each having first ends coupled to the heat plate and second ends situated in a condensation section where at least one of the heat pipes has a different working fluid than an other.
    Type: Grant
    Filed: November 12, 1996
    Date of Patent: March 28, 2000
    Assignee: General Electric Company
    Inventors: Albert Andreas Maria Esser, James Patrick Lyons, Lyle Thomas Keister, Steven Wade Sutherland, Melvin La Vern Hughes, Howard Ross Edmunds, Stephen Daniel Nash, Paul Stephen Pate, Patrick Henry McGinn, Conrad Angelo Pecile
  • Patent number: 5892643
    Abstract: A power device control system includes a power device having an input gate and first and second output terminals, a controller, and a gate driver for supplying current to the input gate of the power device, comparing a voltage difference between the first and second output terminals, and providing a comparator signal to the controller if the voltage difference is greater than or equal to a predetermined maximum voltage difference. The controller is capable of providing a command signal to the gate driver and pulse width modulating the command signal upon receiving a comparator signal from the gate driver to gradually switch off the power device. The control system can further include a current sensor coupled between one of the first and second output terminals and the controller for supplying a current signal and an integrated current signal to the controller.
    Type: Grant
    Filed: July 7, 1997
    Date of Patent: April 6, 1999
    Assignee: General Electric Company
    Inventors: Albert Andreas Maria Esser, Lee Burton Silverthorn, Lyle Thomas Keister
  • Patent number: 5689394
    Abstract: A power device control system includes a power device having an input gate and first and second output terminals, a controller, and a gate driver for supplying current to the input gate of the power device, comparing a voltage difference between the first and second output terminals, and providing a comparator signal to the controller if the voltage difference is greater than or equal to a predetermined maximum voltage difference. The controller is capable of providing a command signal to the gate driver and pulse width modulating the command signal upon receiving a comparator signal from the gate driver to gradually switch off the power device. The control system can further include a current sensor coupled between one of the first and second output terminals and the controller for supplying a current signal and an integrated current signal to the controller.
    Type: Grant
    Filed: December 4, 1995
    Date of Patent: November 18, 1997
    Assignee: General Electric Company
    Inventors: Albert Andreas Maria Esser, Lee Burton Silverthorn, Lyle Thomas Keister