Solution Electrical Numerical 18

Numerical 18: A 4-pole machine running at 1500 r.p.m. has an armature with 80 slots and 6 conductors per pole. The flux per pole is 6 x $\displaystyle \mathrm{10^6}$  lines. Determine the terminal e.m.f. of d.c. generator if the coils are lap connected. If the current per conductor is 100 A, determine the electrical power.

Solution: P = 4

N = 1500

Z = 80 x 6 = 480

ф = 6 x $\displaystyle \mathrm{10^6}$ Lines

1- weber = $\displaystyle \mathrm{10^8}$ Lines 

thus, ф = 0.06 wb

Current per conductor = 100 A

thus, I = 100 x 4 = 400 A

for lap connection A=P

Back emf;

$\displaystyle \mathrm{E_b =\frac{\phi ZN}{60}\times \frac{P}{A}}$ 

$\displaystyle \mathrm{E_b =\frac{0.06\times 480\times 1500}{60}\times 1}$ 

Power = $\displaystyle \mathrm{P\ =\ E_b\times I = 720\times 400\ =\ 288000W = 288kW}$