Question

A hybrid VR stepping motor has 8 main poles which have been castellated to have 5 teeth each. If the rotor has 50 teeth, calculate the stepping angle.
1. 18°
2. 36°
3. 1.8°
4. 3.6°

Answer 1

Correct Answer - Option 3 : 1.8°

Concept:

A hybrid stepper motor is a combination of variable reluctance and permanent magnet-type motors. The rotor of a hybrid stepper motor is axially magnetized like a permanent magnet stepper motor, and the stator is electromagnetically energized like a variable reluctance stepper motor

The step angle of the stepper motor is defined as the angle traversed by the motor in one step.

Step angle of the hybrid stepper motor is given by
\(\beta =\frac{{N_r -N_s}}{{N_s\times N_r}}\times 360^\circ \)

Where N_s = Number of stator teeth 

N_r = Number of rotor teeth

Calculation:

Given that, N_r = 50

N_s =  8 x 5 = 40

∴ stepping angle can be calculated as 

\(\beta =\frac{{50 -40}}{{50\times 40}}\times 360^\circ \)

β = 1.8°