Experience with Large Hydro-Generators at Grand Coulee

The design and construction of the three 826 MV-A hydro- generators for The Grand Coulee Third Power Plant represents a significant achievement. A number of factors conspired to create a situation wherein local contact occurred between the stator and rotor of one unit. This paper outlines the events leading up to this incident, describes investigative work and remedial measures taken to re-establish the intended design parameters.