Question

If short pitch angle of a 3-$\phi$, 2 pole synchronous machine is \(30^\circ\), then pitch factor is

• A. \( \frac{\sqrt{2} - \sqrt{3}}{\sqrt{2}} \)
• B. \( \frac{\sqrt{2} + \sqrt{3}}{2} \)
• C. \( \frac{\sqrt{2} - \sqrt{3}}{2} \)
• D. \( \frac{\sqrt{2} + \sqrt{3}}{2} \)

Hint:

Pitch factor \( k_p = \cos(\alpha/2) \), improves harmonic performance.

Answer 1

The Correct Option is D

Pitch factor \( k_p = \cos(\alpha/2) \), where \( \alpha \) is short-pitch angle.
Here, \( \alpha = 30^\circ \Rightarrow k_p = \cos(15^\circ) = \frac{\sqrt{2} + \sqrt{3}}{2} \)