Dec 14

Skew Angle for Zero Cogging Torque

A new feature in MotorSolve version 6.0 automatically calculates the skew on the stator lamination which is necessary to achieve zero cogging torque.

Given a machine such as shown below :

24 slot, 20 pole Brushless IPM Machine
Figure 1 : 24 slot, 20 pole Brushless IPM Machine

MotorSolve uses the Duane Hanselman relationship to predict the skew which will produce zero Cogging Torque.

The predicted skew value
Figure 2 : The predicted skew value


The Stator input editor then allows one to enter the predicted skew as shown in Figure 3.

Setting the corresponding skew for the Stator Lamination
Figure 3 : Setting the corresponding skew for the Stator Lamination


Figure 4 below shows the original Cogging Torque which was computed by MotorSolve without skew. The peak of the Cogging Torque is nearly 2 ft-lbs.

The Cogging Torque without skew
Figure 4 : The Cogging Torque without skew


Figure 5 below shows the Cogging Torque which was computed by MotorSolve with the predicted skew in place. The Torque is effectively zero.

The Cogging Torque with skew
Figure 5 : The Cogging Torque with skew


Figure 6 below shows the Cogging Torque which was computed by MotorSolve with the predicted skew in place.  The scale on the Torque axis has been adjusted by 5 orders of magnitude to show that indeed the resulting Cogging Torque is zero.

The Cogging Torque with skew [zoomed in scale]
Figure 6 : The Cogging Torque with skew [zoomed in scale]


Pricing and Availability

MotorSolve v6 is now available for Microsoft Windows 7, 8 or 10. For information about the full list of improvements, request a demo, quote or full feature evaluation, please contact an Infolytica Corporation representative nearest you.