Varivolt auto transformer is a continuously variable voltage auto transformer, having a movable carbon tip, fixed to brush arm sliding on a silver plated commutator. Rotation of the brush arm by either manual or motor drive, delivers an output voltage from zero to or above line voltage. Manufactured by Voltamp Controls (India), Varivolt conforms to IS 5142. Features: rugged construction, excellent regulation, high efficiency, no wave form distortion, silver plated commutator, over-load capacity, low operating torque, smooth and linear output, low magnetizing current, negligible maintenance and trouble free long life. Varivolt is now available in high current ranges from 225 A up to 2000 A, in single, two and three phase models. Special paralleling techniques designed by the company has made it possible to surpass the previous current limit of 200 A for toroidal auto transformers.