Effect of radial rotor ventilation ducts on cage motor equivalent circuit parameters

Abstract

A three-dimensional finite-element model is used to investigate the effect that radial ventilation ducts have on the equivalent-circuit parameters of cage motors. It is shown that ducts change rotor resistance at starting, and an approximate method is proposed to allow for this effect. Detailed flux calculations are also used to verify some of the duct factors that are currently used for reactance calculations.