Teledyne Industries, Inc.

Deltec Electronics Corporation

Cambridge Continuous Power

Suresh C Gupta

Robert H Lee

A power supply typology in which the pulse width modulated invertor switches serve two functions; conversion of the a.c. input to a d.c. rail voltage in addition to inversion of the d.c. rail voltage to a regulated a.c. output. An a.c. input ground terminal is connected to a node between two of the invertor switches and this node is also connected to the a.c. output to provide a common ground between the a.c. input and the a.c. output. A silicon control rectifier switch and one of the invertor switches connected to the ground node connect the back-up battery to the a.c. source during positive half cycles of the a.c. input in order to maintain a charge on the back-up battery.

Uninterruptible power supply with a back-up battery coupled across the

A circulating load apparatus for loading a power supply. The power supply has a power input terminal, a power output terminal and a power return terminal. The power supply provides an output voltage at the power output terminal with respect to the power return terminal. The output voltage of the power supply is controlled to be substantially identical in amplitude to the network voltage of a network source, provided at a network source terminal with respect to a source return terminal. The power supply, power return terminal is coupled to the network source, source return terminal. The power supply power input terminal is coupled to the network source terminal to be powered by voltage and current from the network source terminal. The circulating load apparatus has a voltage source for supplying a voltage between a first and second terminal. The voltage source is connected in series between the network source terminal and the power supply power output terminal. The output voltage of the power supply and the voltage source add to provide output power to the network source. An adjusting circuit adjusts the voltage of the voltage source to position the output current of the power supply within a predetermined range to deliver power from the power supply to the network source.

Circulating load apparatus

Methods and apparatus are disclosed for synchronizing multiple AC motor driven synchronous generators to the voltage on a common output bus. In one method, the rotating motor is disconnected from its AC power source, the generator voltage is phase synchronized to the output bus voltage, and then the generator rotor is caused to slip one generator pole at a time until the motor generated voltage is phase synchronized to the AC power source voltage. At that point, the motor is reconnected to the AC power source. Other methods are disclosed in which magnetic position sensors are employed to provide an indication of when the rotors on multiple motor driven generators are mechanically phase synchronized.

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Los Alamitos, CA, United States of America

Suresh C Gupta