Question

Which of the following is the effect of non-uniform armature current?

(a) Ratio of peak to average and rms to average armature current decreases

(b) Ratio of peak to average and rms to average armature current increases

(c) Ratio of peak to average increases and rms to average armature current decreases

(d) Ratio of peak to average decreases and rms to average armature current increases

This question was posed to me in semester exam.

Asked question is from DC Motor Control Through Converters in section Motor Control by Static Power Converters of DC Machines

Answer 1

The correct option is (b) Ratio of peak to average and rms to average armature current increases

To explain I would say: The armature current sometimes due to some reasons may become non-uniform. In this conditions motor performance deteriorates with discontinuous armature current. So, the ratio of peak current to average current increases. Also, rms to average armature current increases.