Question

A 4 pole, lap wound dc generator has a useful flux of 0.07 webers per pole. Calculate the generate emf when it is rotataed at a speed of 900 RPM with the help of prime mover. Armature consists of 440 no of conductors. Also calculate the generated emf if lap wound armature is replaced by wave woumd armature.

Answer 1

Answer:

Very Easy - Lol -

P = 4 Z = 440 Φ = 0.07 Wb and N = 900 r.p.m. is the Answer.

Answer 2

Answer:

• In-lap wound generator  $E = 420V$
• In wave wound generator $E = 840V$

Explanation:

• Given,

Number of poles of a lap wound D.C generator $P =4poles$

Useful flux Ф $= 0.07Webers/pole$

Speed of rotator $Z = 900 RPM$

Number of conductors $N = 400 conductors$

For lap winding, the number of parallel paths $A = P$

we know that,

• $E =$ Ф $(\frac{ZNP}{60A})$

where,

$E =$ emf generated

Ф = useful flux

$Z =$ speed of rotator

$P =$ number of poles

$N=$ number of conductors

$A =$ number of parallel paths

Substituting the known values in the  above formula,

$E =$ Ф $(\frac{ZNP}{60A})$

$E = \frac{0.07*900*440 }{60}$

$E = \frac{25200}{60}\\ \\E = 420V$

In the case of lap winding emf generated is  $E = 420V$.

• In wave wound armature,

Number of parallel paths $A = 2$

• $E =$ Ф $(\frac{ZNP}{60A})$

       $E = \frac{4*0.07*900*440 }{60*2}$

$E = 840V$

Therefore, in the case of wave wound armature generated emf $E = 840V$.

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