This paper presents a method for calculating the iron loss of the stator core of an electric motor owing to the
stress generated by shrink fit tolerance in the production process. Shrink fit is used to fix the frame and stator
core, shaft, and rotor core in a motor, and the corresponding condition varies depending on the material. Three
finite element analysis steps were performed to reduce the iron loss owing to stress during shrinking of a frame
and stator core. In step 1, the shrink fit process was applied to a frame and stator core, considering the manufacturing
tolerances through three-dimensional modeling. Thermal-structure finite element analysis was performed
to apply the same conditions as those in the shrink fit process. The shrink fit was expanded by applying
heat to the frame, followed by natural cooling to calculate the contact stress between the frame and the stator
core. In step 2, the same contact stress as that in step 1 was derived using structural analysis through twodimensional
modeling of the frame and stator core without tolerances. The contact stress was calculated by
applying the equivalent thermal expansion coefficient of the frame, and it was confirmed that the manufacturing
tolerance and maximum stress intensity are linearly related. In step 3, electromagnetic analysis was performed
at the rated operating point of the 2.2-kW induction motor using the model obtained in step 2. The
magnetic flux density distribution of the stator core was derived via electromagnetic analysis and the iron loss,
including the stress distribution, realized in step 2. The iron losses obtained under different conditions, including
the stress of the stator core owing to the shrink fit tolerance, were compared, and the effectiveness of the
shrink fit tolerance required to achieve a motor with high efficiency was evaluated.