Question

In 4-point starters the resistance is added in series with NVC because __________________

(a) To increase field current

(b) To increase armature current

(c) To limit the NVC current

(d) To limit armature current

I have been asked this question by my college director while I was bunking the class.

Question is from Starting of DC Motors in chapter DC Motors of DC Machines

Answer 1

The correct answer is (c) To limit the NVC current

Explanation: To overcome the problem caused when the field current is low, NVC is connected across the two lines, one line connected to F terminal through the starter and other directly to the second line from another L terminal of the starter. To limit the NVC current a protective resistance R is connected in series with it.