Abstract: A method for shorting rotor windings in a wound rotor induction machine is disclosed. The method includes the steps of monitoring rotor current for a frequency indicative of a desired steady-state operating condition and electronically shorting the rotor windings when the monitored rotor current frequency reaches a defined threshold indicative of the desired steady-state operating condition.

Abstract: A method for shorting rotor windings in a wound rotor induction machine is disclosed. The method includes the steps of monitoring rotor current for a frequency indicative of a desired steady-state operating condition and electronically shorting the rotor windings when the monitored rotor current frequency reaches a defined threshold indicative of the desired steady-state operating condition.

Abstract: It is possible to monitor the performance of a lubrication system performance of a Dynamoelectric Machine (DEM) by observing the electric current flowing in the DEM shaft. Suitable Rogowski coils are mounted around the shaft of the rotor of a DEM just inboard the bearings. The Rogowski coil may be mounted on the shaft to rotate with the shaft, or it may be mounted on said DEM so as to surround the shaft and remain stationary. Shaft current magnitudes may be established for start-up and steady state operating conditions. Any deviation from the steady state shaft current magnitude may be taken as a warning that the DEM bearing lubrication system is malfunctioning.

Abstract: Some dynamoelectric machines develop shaft E.M.F.'s during operation which lead to circulation currents in the shaft of the machine. The shaft current will attempt to flow through the bearings of the machine, unless some action is taken to prevent or limit said current flow. This invention minimizes the circulation of rotor shaft currents by providing a return path for the shaft current through an insulated conductor located in the center of the shaft of the machine. The insulated conductor is electrically attached to the shaft at the ends of the conductor. The conductor may extend the length of the shaft.

Abstract: A dynamoelectric machine has a stator with a stator core and a plurality of spaced apart radially extending ventilation ducts. A rotor mounted for rotation within the stator has a shaft with a plurality of salient poles. Each salient pole has a winding on it and each pole with its winding constitutes a pole member. Adjacent pole members define between them an interpolar space. Cooling air enters each interpolar space from each end when the machine is operating, moves generally axially as portions of the air change direction to move radially outwards through the air gap separating the rotor and stator and then through the ventilation ducts. The air flow, in a radial outward direction, tends to be less at the ends of the rotor and through the ventilation ducts adjacent the ends of the stator. The invention places a baffle at each end of each interpolar space.