Question:-
A 220 V shunt motor has an armature resistance of 0.2 and field resistance of 110 ohm. The Motor draws 5A at 1500 r.p.m. at no load. What is the speed, if motor draws 52A at rated voltage.
Option (A)
1136 r.p.m
Option (B)
1236 r.p.m
Option(C)
1436 r.p.m
Option(D)
1500 r.p.m
Correct Option:
(C)
Question Solution:
Ish = (220/110) 2A
Ia1 = 5-2 = 3A
Ia2 = 52 -2 = 50A
Here Eb1 = 220 - 3 x 0.2 = 219.4 volt
Eb2 = 220 - 50 x 0.2 = 210.0 volt
So (N2/1500) = (210/219.4)
→ N2 1436 r.p.m
question-answer-faq-1634