Abstract: Grouped gating control logic allows for one or more inputs in a group to be active at any given time. Once an input signal in a group is active, all other pulse trains received in the same group can be locked out. Thus, by using a finite state machine to control gate pulses, the noise margin of the gating unit can be regulated and an extra level of protection is available should one of the input gating signals be defective.

Abstract: An apparatus and method for providing a supply of air to cool electrical devices is provided. The apparatus comprises a two fan housings, each containing a number of fans arranged to blow air in a parallel fashion. The exhaust of one housing is connected to the intake of the other housing by a balancing plenum. The apparatus provides a sufficient supply of cooling air when one or more of the fans is inoperable. The device being cooled may be the power bridge of an exciter for a power generation system. A method for providing a supply of air to electrical devices is also provided.

Abstract: A fluid filled transformer including a tank for containing at least primary and secondary windings, a radiator connected to the tank via top and bottom headers, a fluid disposed in the tank, a fluid circulation flow path including passages through the windings, radiator, headers, and at least a portion of the tank, and at least one diagnostic sensor disposed within the fluid circulation flow path for measuring properties of the fluid. By positioning the sensor within the circulation flow path, measured values are more reliable, accurate, and efficiently sensed.

Abstract: An apparatus and method for detecting short circuits in a power conversion circuit and a motor drive incorporating the same. The circuit is gated and subsequently a DC bus charger is activated. Charge on the DC bus is measured to indicate a short circuit. After a test iteration, a protective circuit is activated to discharge the DC bus to permit another test iteration to be accomplished quickly.

Abstract: A method and apparatus for transferring an AC machine between non volts per hertz drive and a power supply such as supply mains, or a generator. In a transfer procedure, the motor drive is placed in a quasi-voltage mode prior to transfer to permit the output of the motor drive to be synchronized to the output of the power supply. In capture procedure, the output of the drive is preconditioned based on detected states of the AC machine to synchronize the voltage at the terminals of the AC machine with the output of the drive. During the capture procedure, opening of a contactor is detected by comparing the frequency and/or voltage at the terminals of the AC machine with that of the power supply.