Influence of rotor currents on end-winding forces in cage motor

The authors propose a simple model that enables the influence of rotor currents to be included in the calculation of the electromagnetic forces acting on the end windings of cage induction motors, using the Biot-Savart method. The inclusion of the rotor currents is shown to have greatest influence close to core, where the end-region fields are also highest. The validity of the model is established using experimental measurements of flux density made on a two pole machine. Calculated force distributions show the effect of the rotor currents to be significant enough to merit their inclusion in the model