Question

A 3 phase,50hz, 2 pole, star connected alternator pitch factor 0.9932 & distribution factor of 0.9554. The generated Emf line value is 3300v. Find the useful flus per pole? ​

Answer 1

Answer:

Pitch factor:

Pitch factor is defined as the ratio of the induced emf per coil when the winding is short-pitched to the induced emf per coil when the winding is full pitched.

It is given by Kp = cos (α/2)

Where α is the short pitch or chording angle

Explanation:

Calculation:

Given that,

Slots S = 72

Slots/pole/ph = m = 72/ (8×3) = 3

Pole pitch = S/P = 72 / 8 = 9

Pole pitch = 180° = 9 slots

⇒ Each slot = 20°

The coils are short pitched by 3 slots.

⇒ Chording angle α = 3 × 20 = 60°

⇒ Pitch factor is given by Kp = cos (60°/2) = cos 30° = √3 / 2