Prevention of Rotor-Winding Deformation on Turbogenerators

During recent years there have occurred several cases of failures on turbogenerators which were found to be due to a singular type of deformation of the rotor windings. It is recognized that the deformation of rotor windings is due to forces set up in the windings by the interaction of centrifugal force and temperature change.¹ The purpose of this paper is to discuss briefly the phenomena responsible for this type of deformation, and to show that by means of preheating of the rotor windings to a definite predeterminable winding temperature, the resulting mechanical stresses can be very materially reduced so that winding deformation is held to a minimum.