Radiotone Double Layer Roller Contact Vertical Variable Autotransformers (colloquially known as Variac) is also a 3 phase transformer, however, with each limb having one winding inside. The top winding is connected in series with inside winding. The Carbon brushes are on the outer load winding.
Radiotone Double Layer Roller Contact Vertical Variable Autotransformers (colloquially known as Variac) has special application in Servo controlled Voltage Stabilizer with balanced loads & balanced input conditions. It can also be used for unbalanced load conditions up to a certain extent. This eliminates the requirement of 3 phase buck boost transformer, thus making the Tank Size very compact.
Further models are under development.
