A 4 pole DC generator rotates at 1500 rpm.
How many times in a second, will the emf induced in each armature conductor changes its direction?
A. 750.
B. 100.
C. 500.
D. 200.
Answer: B
Share your understanding of this question with the correct explanation.
The number of times the emf induced in each armature conductor changes its direction in a DC generator is determined by the number of pairs of poles and the rotational speed.
In a 4-pole generator, each pair of poles consists of a North pole and a South pole. As the armature rotates, the magnetic field alternates between these poles, causing the emf induced in each armature conductor to change its direction.
Since the generator rotates at 1500 rpm (revolutions per minute), it completes 1500/60 = 25 revolutions per second. In each revolution, the armature passes through one complete cycle of changing magnetic field (from North to South and back to North).
Therefore, the emf induced in each armature conductor changes its direction 25 times per second.
The correct answer is option B: 100.