Correct Answer - Option 3 :
0.707
Concept:
The pitch factor for nth harmonic is given by,
\({k_c} = \cos \frac{{nα }}{2}\)
where α is the slot angle
Calculation:
The first coil lies in slots 1 and 16
Coil span is 16 – 1 = 15 slots
Number of empty slots = 18 – 15 = 3 slots
\(\therefore \alpha = 180^\circ \times \frac{3}{{18}} = 30^\circ\)
Pitch factor for 3rd harmonic, \({k_{{c_3}}} = \cos \left( {\frac{{3 \times 30^\circ }}{2}} \right)\)
= 0.707
