Gary Randall Barnes

Wind generators as compared to large heavy duty power generators

Wind turbine generators are different than conventional thermal turbine-generators both in the types of machines used as well as the type of application and environment in which the machines operate. The wind generator and its converter have several common configurations, rotor types, and operational duties that are not commonly encountered in large power plants. Those differences are discussed in regard to machine design aspects, such as winding insulation, as well as environmental factors and maintenance factors.

Fretting Fatigue Modeling and Repair Evaluation for Generator Rotors

Generator Rotor Tooth Cracks have been recently observed on some long service generator rotors. The purpose of this paper is to document the root cause analysis as well as a repair methodology that was developed in support of one of these cracked units. The paper discusses the development of a finite element model to understand the operating modes and failure mechanisms that caused the initiation of these cracks. The results of the analysis agreed very well with field observations on cracked units and with some limited repair options that have been successfully used in the past. An experimental fretting fatigue testing program is currently underway to substantiate and extend the results reported in this paper.Copyright