Variable Reluctance Motors Animated

Appendix to Stepping Motors Types by Douglas W. Jones
Here is Figure 1.1 in animated form: 
Figure 1.1 

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In looking at this figure, note the following:
  1. The field appears to rotate counterclockwise while the rotor rotates clockwise. This arrangement is common with variable reluctance motors.

  2. The field rotates in steps of 60 degrees while the rotor moves in 30 degree steps (in the opposite direction). This is reminicent of the motion of the scale of a vernier caliper, and for this reason, variable reluctance motors are sometimes known as vernier motors.

  3. It takes four complete cycles of the control system to rotate the motor rotor through one cycle. This is because the rotor has 4 poles!