Overview
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Spindle motors with permanent magnets can be small-sized and produce high
torque. To improve the general performance of the spindle motor, the effects
of the 3D geometry and magnetic saturation should be included in the analysis.
This note shows the Speed-Torque curve and Torque-Current curve of a spindle
motor obtained from an analysis. |
Speed-Torque Curve and Torque-Current Curve
Figure 1 shows the Speed-Torque curve, and Figure 2 shows the Torque-Current
curve.
The results show that the torque decreases as the speed increases, and
it increases as the current increases. The torque is almost proportional
to the speed, meaning that the effect of the coil inductance is very little. |
Closeup |
Closeup |
Magnetic Flux Distribution
Closeup |
Figure 3 shows the magnetic flux density distribution in the rotor core
at 7200 rpm.
It is seen that the magnetic flux is not uniformly distributed in the axial
direction. The magnetic flux density is high in the rotor core because
the rotor core is thin in the magnetic flux direction of the coil. High
magnetic flux density causes magnetic saturation, which can lead to a decrease
in torque. |
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