Auto Transformer
Auto transformer is also voltage transformer. The auto transformer is based on the characteristicks of the tapped windings. This device is really more in the nature of a circuit arrangement than a distinct breed of component aspect. In some special cases, electrically it is almost identical with the supply in the normalway. But the secondary is connected in series with the supply so that its voltage adds to the supply voltage when the output is taken across the both windings. Auto transformer generally is used to obtain small increments of voltage above the input voltage.

Specification:
Product Ranges: 1 MVA to 5 MVA
Voltage Class: 230V-25%, 50%, 75%,100% taps
415V-25%, 50%, 75%,100% taps
3300V-25%,50%,75%,100% taps
6600V-25%, 50%, 75%, 100% taps and also with special type customerm requirement.
Cooling: Oil Cooled/Air Cooled
Type: OFF-LOAD type

YYn 11 Vector Group:
Y: The winding primary is connected in Star
Y: The winding secondary is connected is Star
n: Neutral brought out in 11 'O' Clock
11: Position is called n(120 Deg. Phase angle)