Analytical modeling of eddy current loss in retaining sleeve of surface-mounted PM machines accounting for influence of slot opening

This paper presents an analytical model for predicting the open-circuit, armature reaction, and load eddy current loss in the conductive retaining sleeve of surface-mounted permanent magnet machines accounting for slot opening and tooth-tips. The finite element results confirm the high accuracy of the developed model and the necessity of accounting for the slot opening. The load sleeve loss is equal to the sum of the open-circuit and armature reaction sleeve losses when the q-axis current is applied only, but less than their sum in the flux weakening operation. When the slot opening increases, the open-circuit sleeve loss significantly increases, but the armature reaction sleeve loss slightly reduces. Hence, the overall load sleeve loss increases with the slot opening.