Application Catalog
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| 159 - Influence Analysis of Dimensional Tolerance using Morphing <DP> |
Overview
Closeup |
The angle of the magnets in SPM motors use a fillet or chamfer. However,
the fillet and chamfer of each product that is manufactured varies because
to completely fabricate the same fillet or chamfer is difficult in the
manufacturing process. Therefore, the dimensional tolerance is set so the
motor performance is not affected by these variations.
This example presents the use of a magnetic field analysis to compare whether
the cogging torque of the SPM motor is influenced by changing geometry
in the tolerance range assuming the dimensional tolerance of the chamfer
is ±0.4 mm. |
Cogging torque
The cogging torque waveform is indicated in Fig. 1 and the frequency components
of the cogging torque are indicated in Fig. 2. The position of the peak
value shifts as the dimensions of the chamfer change, but the peak value
remains almost the same, as indicated in Fig. 1. The variations of the
fundamental frequency of 360 Hz are smaller than the harmonic components,
as indicated by the frequency components in Fig. 2.
Therefore, the variations of the geometry in the tolerance range of the
chamfer only affect the cogging torque minimally. |
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Back EMF
The back EMF waveform is indicated in Fig. 3 and the frequency components
of the back EMF are indicated in Fig. 4. The value of the back EMF is almost
the same even when the dimensions of the chamfer are changed, as indicated
in Fig. 3. The variations of the fundamental frequency of 60 Hz are smaller
than the harmonic components, as indicated by the frequency components
in Fig. 4.
Therefore, the influence of the chamfer tolerance is minimal. |
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Updated: 2011-02-28
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