Siemens Westinghouse Power Corporation

Westinghouse Electric Corporation

Abraham Nieves

Robert John Nelson

James Frederick Lau

Aleksandar Prole

Stephen W Cates

Charles L Senic

Robert W Ramsay

Methods and systems consistent with the present invention provide improved online detection of one or more shorts in rotor turns () of a field winding () of an electric generator. An initial reference inductance Lis determined by an impedance-measuring circuit (). A subsequent inductance L is determined by the impedance measuring circuit (). A data processing system () compares Lto L to determine whether they differ by a predetermined amount. If Land L differ by the predetermined amount, an alarm is provided to operators to indicate the presence of one or more shorted rotor turns.

Method and apparatus detecting shorted turns in an electric generator

The present invention monitors an electrical generator ( ) to provide an indication of a problem in the generator's bearing insulation ( ), such as insulation damage or insulation bridging, and sets an alarm to warn an operator of the problem, thereby avoiding damage to the electrical generator ( ). Methods and systems consistent with the present invention identify problems with bearing insulation ( ) by monitoring the naturally occurring shaft voltage on the generator rotor ( ) and by setting an alarm if the shaft voltage drops below a predetermined value.

Method and system for on-line monitoring of bearing insulation in an electrical generator

A half-coil for the stator winding of an electrodynamic system such as an electrical generator or motor includes an improved tube stack arrangement and a roebelling configuration which is designed to minimize power loss. The tube stack arrangement includes, in the disclosed embodiment, two central tube stacks and two roebel bars, one on each side of the tube stacks. By this arrangement, the individual strands in the roebel bars do not need to be transposed around the tube stacks, as was the case in prior art configurations utilizing more than one tube stack. The improved roebelling arrangement includes, in the disclosed embodiment, a total 720.degree. transposition, including a 90.degree. transposition in each of the two involute portions. To accomplish the 720.degree. transposition in a limited space, the individual strands are combined into groups of two for a portion of the transposition.

Half-coil configuration for stator

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Orlando, FL, United States of America

Abraham Nieves