Question 18.5: Step Angle Determination of VR Step Motor Determine an expre...
Step Angle Determination of VR Step Motor
Determine an expression for the step angle of a VR step motor based on the number of teeth on the rotor and stator and on the number of phases.
Known Quantities: Number of rotor and stator teeth; number of phases.
Find: Step angle.
Schematics, Diagrams, Circuits, and Given Data: t= number of teeth =4;m= number of phases =3.
Analysis: The number of steps in a revolution, N, is given by the product of the number of teeth and the number of phases (e.g., in the preceding example it is equal to 2 teeth \times 4 phases =8 steps). Thus, N=t m.
The step angle increment, or resolution, is equal to \Delta \theta=360^{\circ} N . For the motor described in this example,
\Delta \theta=\frac{360^{\circ}}{N}=\frac{360^{\circ}}{t m}=\frac{360^{\circ}}{12 \times 3}=10^{\circ}