nAutotransformer(Elec) A transformer in which part of the primary winding is used as a secondary winding, or vice versa; -- called also a compensator or balancing coil.
Century Dictionary and Cyclopedia
nautotransformerIn electricity, a transformer, in which a part of the primary coil is used as secondary coil, or inversely. Frequently this part of the coil may be variable and so permit a regulation of the voltage. The autotransformer has the advantage, compared with the transformer, of smaller size and higher efficiency, but the disadvantage of connecting the primary and the secondary circuit together electrically. See transformer. Also called compensator.