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SarkariResultOutBMS · 2024

Previous Year Question

The main advantage of distributing the winding of a synchronous generator in slots is to
  1. Reduce the size of the machine
  2. Add mechanical strength to the winding
  3. Reduce the amount of copper required
  4. Reduce the harmonics in the generated EMF

Correct answer: D

Explanation

Distributing a phase winding among several slots makes the resultant air-gap mmf and generated emf more nearly sinusoidal and reduces selected harmonic components. This improves waveform quality, which is the principal advantage stated in option D.

Formula

Distribution factor kd<1 for harmonics; distribution helps suppress harmonic emf

Step-by-step solution

Harmonic Reduction and Waveform explanatory diagram

Correct Answer

D — Reduce the harmonics in the generated EMF

Concept and Reasoning

Distributing a phase winding among several slots makes the resultant air-gap mmf and generated emf more nearly sinusoidal and reduces selected harmonic components. This improves waveform quality, which is the principal advantage stated in option D.

Calculation / Key Relation

Distribution factor kd<1 for harmonics

distribution helps suppress harmonic emf

Exam Takeaway

Distributed winding → smoother, more sinusoidal mmf/emf.

Common Mistake

Do not view the reduction in fundamental winding factor as the desired advantage; harmonic reduction is the benefit.

Common mistake

Do not view the reduction in fundamental winding factor as the desired advantage; harmonic reduction is the benefit.

Exam tip

Distributed winding → smoother, more sinusoidal mmf/emf.

Quick method

Distributed winding → smoother, more sinusoidal mmf/emf.