Features . High response, low inertia rugged A. C. servo motor. Critically damped response on all loadssupply conditionsli>. Energy savings due to high efficiency and superior transformer design. High quality raw materials used prime grade CRGO lamination and high purity electrolytic copper wiresstrips used. High speeds of correction up to 35Vsec for three phase and 20Vsec for single phase. Machine wound variacs with special carbon brushes for enhanced life. Simple, systematic construction for dependability and ease of maintenance. Solid state control circuitry