Question

What is the formula for the rms value of the end ring current?

(a) rms value of end ring current = (bars per pole * current per bar) / (3.14*no of poles)

(b) rms value of end ring current = (bars per pole * current per bar) * (3.14*no of poles)

(c) rms value of end ring current = (bars per pole * current per bar) / (no of poles)

(d) rms value of end ring current = (bars per pole * current per bar) / (3.14+no of poles)

I have been asked this question in quiz.

My query is from Design of End Rings topic in section Three Phase Induction Motor of Design of Electrical Machines

Answer 1

Right option is (a) rms value of end ring current = (bars per pole * current per bar) / (3.14*no of poles)

The explanation is: First the bars per pole is obtained. Then the current per bar is calculated and the no of poles is calculated. Substituting in the above formula, the rms value of the end ring current is obtained.