Overview
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Shrink fitting is a fastening method that uses heat to fasten two metal
parts together.
The internal stress produced by the clearance causes the magnetic properties
to weaken and the iron losses to increase.
Therefore, evaluating iron losses that include the stress produced by the
clearance is important during the design stage.
This example presents the use of a magnetic field analysis to obtain the
iron loss density of an IPM motor with and without the stress. |
Compressive Stress Distribution
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The compressive stress distribution is indicated in Fig. 1. The compressive
stress caused by the frame shrinking in the radial direction increases
around the slots. This is because the stress decreases towards the tips
of the teeth while the stress is concentrated around the slots. |
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 60 % due to the stress. An analysis that
accounts for the thermal stress caused by shrink fitting needs to be performed
to evaluate the iron losses more accurately because the iron losses increase
when the stress is applied. |
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