Abridgment of transformers with load ratio control

In the last eight years voltage regulation on transformers under sustained load has made rapid strides and found very wide application in extended power systems and on industrial loads. Originally it was found economical to equip for load ratio control only very large transformers using apparatus designed for high currents. This paper describes and compares with earlier developments a novel equipment of low-current rating that has been devised especially to control small blocks of power, thereby greatly widening the economic field of application of load ratio control. Particularly are the electromechanical features of this equipment stressed.