AUTO TRANSFORMER
An autotransformer (sometimes 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 sides of the transformer. The winding has at least three taps where electrical connections are made. Since part of the winding does “double duty”, autotransformers have the advantages of often being smaller, lighter, and cheaper than typi-cal dual-winding transformers, but the disad-vantage of not providing electrical isolation. Other advantages of autotransformers include lower leak-age reactance, lower losses, lower excitation current, and increased KVA rating for a given size and mass.
Operations:
Autotransformer is a transformer in which the primary and secondary coils have part or all of their turns in common. The primary voltage is applied across two of the terminals, and the secondary voltage taken from two terminals, almost always having one terminal in common with the primary voltage. The primary and secondary circuits have a number of windings turns in common.
Applications:
- In Power transmission and distribution.
- In industry is to adapt machinery built.
- Provide conversions between the two common domestic mains voltage bands in the world.
- On long rural power distribution lines
- A special form of autotransformer called a zig-zag is used to provide grounding on three-phase systems that otherwise have no connection to ground.
- In Audio systems.
- In Railways.
This type of transformer is used in applications where the transformer is to be installed in harsh climatic conditions (smoke, pollution, dusty environment,etc.) or if the transformer is KNAN cooling type.
Auto Transformer
An autotransformer (sometimes 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 sides of the transformer.
lightening transformers
Electrically isolating of the lighting load from main load. Better control on protection systems due to separation of neutral of lighting load & main load