The starting current in the auxiliary and main windings of a single-phase induction motor are 8- -30- A and 8- -60- A- If a voltage 400- 0- V is applied- then ratio of effective resistance of the main winding to effective resistance of auxiliary winding will beupto 3 decimal place

With a voltage nbsp; nbsp;400∠ 0^∘ V, the main winding draws a current of 8∠ 60^∘ A. Effective resistance of main winding =Re [ 400∠ 0^∘8∠60^∘ ] =25Ω n ...

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Standard X

Physics

Electric Motor

The starting ...

Question

The starting current in the auxiliary and main windings of a single-phase induction motor are $8 ∠ - 30^{\circ}$ A and $8 ∠ - 60^{\circ}$ A. If a voltage $400 ∠ 0^{\circ}$ V is applied, then ratio of effective resistance of the main winding to effective resistance of auxiliary winding will be_____(upto 3 decimal place)
0.577

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Solution

The correct option is A 0.577
With a voltage $400 ∠ 0^{\circ}$ V, the main winding draws a current of $8 ∠ - 60^{\circ}$ A.

Effective resistance of main winding $= R e [\frac{400 ∠ 0^{\circ}}{8 ∠ 60^{\circ}}] = 25 Ω$

Effective resistance of auxiliary winding $= R e [\frac{400 ∠ 0^{\circ}}{8 ∠ - 30^{\circ}}] = 43.30 Ω$

$\frac{The effective resistance of main winding}{The effective resistance of auxiliary winding} = \frac{25}{43.30} = 0.577$

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