Question

An ac generator has a coil with 2500 turns and area 4.2x10-3 m^2 the coil rotates in magnetic field of .1T and generates an emf of 240Vrms what is the max magnetic flux through coil ? What is the frequency of generator ?

Answer 1

Given : N = 2500 , A = 4.2×10^-3 m² , B = 0.1 T , = 240 V

Solution :

Step:1

We know that magnetic flux is maximum when = 0.

So maximum magnetic flux is given by :

_B = B.A cos , = 0

_B = B×A

= (0.1T) × (4.2×10^-3 m²)

= 4.2×10^-4 Wb

Step:2

Induced emf is given by :

= NBAsint

Maximum induced emf ,

_o = NBA

= _o / NBA

= (240 V)/(2500*0.1*4.2×10^-3)

= 228.57 rad/s

We know that , = 2f

Where f is the frequency

2f = 228.57

f = 228.57/2

By solving we get ,

f = 36.4 Hz