Curtiss-wright Electro-mechanical Corporation

Westinghouse Electric Corporation

Thomas Andrew Lemak

David Jonathan Hall

Michael Twerdochlib

Robert L Osborne

James P Kapinski

Dennis Pavlik

Regis J Hillenbrand

Systems and methods for improving the current pulse from multiple pairs of pulsed alternators used for driving large loads such as an electromagnetic launcher (i.e., 'rail gun') load. Conventional current pulse ripples are reduced by interleaving pulses from multiple pairs of contra-rotating pulsed alternators. Current pulses supplied by different pairs of pulsed alternators are timed so that they are interspersed between one another to provide more pulses for a given launch time. The interleaved current pulses increase the frequency and reduce the magnitude of the ripple on the average load current.

Ripple reduction in electromagnetic launcher current from pulsed alternators

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.

Transformerless multi-level power converter

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.

Modular linear electric motor with limited stator excitation zone and stator gap compensation

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. The detection circuitry permits reliable monitoring of brush bounce and distinguishes between that condition and brush rub.

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McKeesport, PA, United States of America

Thomas Andrew Lemak