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| Example of the Week |
2012-05-14
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* Iron Loss Analysis of an IPM Motor Including the Effects of the Press Fitting Stress
The laminated structure of a core can be sustained using press-fitting or shrink fitting.
The press-fitting stress needs to be accounted for in the iron loss analysis because the stress caused by press-fitting is known to increase the iron losses when a magnetic steel sheet is used for the core of the motor.
This example presents the use of a structural analysis and magnetic field analysis to obtain the iron loss density of an IPM motor with and without the stress by simulating the stress caused by the press fit core and frame with the press fit condition.
· Minimum Principal Stress Distribution
The minimum principal stress distribution is indicated in Fig. 1. Tensile stress occurs in the frame and teeth, but compressive stress that especially effects the iron losses is produced largely in the yoke. The compressive stress is especially large in the area of the model within the square in Fig. 1, but this is because of the slots' geometry.
· Iron Loss Density Distribution
The iron loss density distribution is indicated in Fig. 2. The iron loss density distribution varies depending on whether or not the stress is applied. The iron losses are increased by 1.5 % due to the stress. An analysis that accounts for the compressive stress caused by the press-fitting needs to be performed to evaluate the iron losses more accurately because the iron losses increase when the compressive stress is applied.
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