The influence of cooling ducts on the leakage inductances of induction machines

In this paper the influence of the cooling ducts on the leakage inductances, and therefore on the breakdown torque, in induction machines is discussed. This effect is typically a three-dimensional one, and one has to analyse numerous geometrical variants. A simplified 3D finite element model of the induction machine is hence used, whose equivalent inductances are calculated. Due to the transversal orientation of cooling ducts, with respect to the main flow paths, the simplified model is able to deliver accurate qualitative results concerning the real machine.