a conventional fully rated two winding transformer.
However, this is only advantageous if relatively close voltage ratios are used. A separate delta connected tertiary winding may be provided for harmonic suppressionorfor the supply of local loads at lower voltages.
These auto-transformers are generally more complex than generator step-up transformers and their dielectric design more difficult. Their performance under short-circuit has also to be carefully analysed at the design stage, as they