General
An auto transformer is a specific type of transformer in which the secondary voltage is directly tapped of the
primary winding. By tapping of the primary winding the secondary output will be realized according the ratio
of the position of this tapping.

Adjustable (variable) transformer
An adjustable transformer (also sometimes referred to as Variac) is a different kind of auto transformer.
By making the primary tapping for the secondary voltage adjustable an adjustable output voltage is realized.

Galvanic isolation
The main difference between auto transformers and isolating transformers is the not-separated windings of
the primary and secondary side. This makes the secondary side of the auto transformer vulnerable to voltage
peaks and disturbance on the primary side.
The advantages of an auto transformer are:
- less winding material needed for the construction
- smaller building size
- cheaper construction
The advantages of an auto transformer increase when the difference between primary and secondary
side are less.

Make: Wesemann Transformatoren
- customized design
- industrial application
- available at 1 piece or more
- rated power up to 150kVA

The Wesemann auto transformers series comply with the standard NEN61558 and are labeled on the
identification tag with the international logo for auto transformers.