Question

Determine the flux per pole for 6-pole dc machine having 240 wave connected conductors, which generates an open circuit voltage of 500 volt, which is running at 1000 rpm.
1. 0.129 Wb
2. 0.021 Wb
3. 0.042 Wb
4. 7 mWb

Answer 1

Correct Answer - Option 3 : 0.042 Wb

Given that, number of poles (P) = 6

Speed (N) = 1000

Number of conductors (Z) = 240

Number of parallel paths (A) = 2

Induced emf (E) = 500 V

Now \(E = \frac{{\phi ZNP}}{{60A}}\)

\( \Rightarrow \varphi = \frac{{500\; \times \;600\; \times \;2}}{{6\; \times \;1000\; \times \;240}}\) 

\(\Rightarrow \varphi = \frac{1}{{24}} = 0.042Wb\)