Question

the armature of a generator of resistance 1 ohm is rotated at its rated speed and produces 125 V without load and 115 V with full load. the current in armature coil is?

Answer 1

Answer: 10 A

Explanation:

Given data:

The resistance of the armature of a generator, R = 1 ohm

The armature is rotating at its rated speed and produces, E = 125 V without load

Now, with full load the rate of rotation of the armature reduces and thereby the back emf becomes, Eback = 115V

To find: the current “i” in the armature coil

Now, By applying the KVL in the loop given in the figure attached below,  

-E + Eback + (i * R) = 0

Rearranging the eq.,

⇒ i = [E - Eback] / R

Substituting the given values ,

⇒ i = [125 – 115] / 1

⇒ i  = 10 A

Thus, the current in the armature coil is 10 A.