Question

In a motor, a rotor is fitted with the armature that has current of 10 A. The rotor rotates with angular speed of 3 rad/s.Magnetic field of magnitude 2 T varies in direction is such a way that it is always perpendicular to the loop area. If the rotor coil has N number of turns and area of each loop is $0.45m^2$ then find the value N. Given that motor consumes 2106 W power and there are no losses.

Answer 1

Given that motor consume $2106$ W power.

Current value=$10A$

Voltage across motor armature=$\frac{2106}{10}=210.6V$

emf induced=$NBA\omega$

$N=\frac{210.6}{BA\omega }$

$N=\frac{210.6}{2\times 0.45\times 3}=\frac{210.6}{2.7}$

$N=78$