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Consider the following given statements about auto-transformers and choose the one which is/are correct. 1. Auto-transformers require less copper as compared to a conventional,2 winding transformer of the same capacity. 2. Auto-transformers provide isolation between the primary and secondary windings. 3. Auto- transformer has less leakage reactance as compared to the conventional, 2 winding transformer of the same capacity.

Consider the following given statements about auto-transformers and choose the one which is/are correct. 1. Auto-transformers require less copper as compared to a conventional,2 winding transformer of the same capacity. 2. Auto-transformers provide isolation between the primary and secondary windings. 3. Auto- transformer has less leakage reactance as compared to the conventional, 2 winding transformer of the same capacity. Correct Answer only 1 and 3

In autotransformer, one single winding is used as primary winding as well as the secondary winding

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Advantages of auto-transformer over a two-winding transformer:

  • More efficient for the same VA rating
  • Smaller in size
  • Require less copper in their construction
  • Cost is less compared to double wound transformers of the same VA rating
  • Core and copper losses are lower due to less resistance and leakage reactance giving a superior voltage regulation than the equivalent two winding transformer

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