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1. AUTO - TRANSFORMERS Made By : Shaikh Zulkar, Shaikh Uvesh, Khan Asif , Abdullah Vohra. Submitted To: M s.Krupul Dhimmar Bhagwan Mahavir University

2. Transformers “ A transformer is a static device which is use to convert high alternatic voltage to a low alternatic voltage and vice versa, keeping the frequency same. "

3. Principle Of Operation “ Transformer works on the principle of mutual induction of two coils. When current in the primary coil is changed the flux linked to the secondary coil also changes. Consequently an EMF is induced in the secondary coil. "

4. Types Of Transformers Auto-transformer Poly- phase transformer Leakage transformer Resonant transformer Instrument transformers

5. Autotransformers “ An autotransformer (som etimes called auto step down transformer ) is an electrical transformer with only one winding. In an autotransformer, portions of the same winding act as both the primary and secondary si des of the transformer. "

6. Theory of Autotransformer 🠶 N1=primary turn(1- 3) 🠶 N2=secondary turn(2 - 3) 🠶 I1=primary current 🠶 I2=secondary current 🠶 V1=primary voltage 🠶 V2=secondary voltage From Figure i we get:

7. Cont.…. (I/P=O/P) OUTPUT The primary and secondary windings of an autotransformer are Connected magnetically as well as electrically. So the power transferred primary to secondary inductively as well as conductively.

8. Types Of Autotransformers Step Up Auto-Transformer Step Down Auto-Transformer

9. Step Up Auto- Transformer “ An autotransformer in which Ns>Np is called a step up autotransformer. A step up autotransformer is a transformer which converts low alternatic voltage to high alternatic voltage. "

10. Step Down Auto- Transformer “ An autotransformer in which Np>Ns is called a step down autotransformer. A step down autotransformer is a transformer which converts high alternating voltage to low alternating voltage. "

11. Advantages Of Autotransformers An autotransformer requires less Cu than a two- winding transformer of similar rating. An autotransformer operates at a higher efficiency than a two-winding transformer of similar rating. An autotransformer has better voltage regulation than a two-winding transformer of the same rating. An autotransformer has smaller size than a two- winding transformer of the same rating. An autotransformer requires smaller exciting current than a two-winding transformer of the same rating.

12. THANK YOU