Electric Motor for Alternating Current

An electric motor was one of the critical components needed to make an electrical power system based on alternating current. Electrical inventor Nikola Tesla developed a revolutionary motor based on electromagnetic induction that featured rotating magnetic fields to drive the central armature. Engineers working for George Westinghouse refined Tesla’s concept and introduced this model A two-phase motor in 1888. The armature core is of the Siemens drum-type, a design intended to minimize the number of wire windings.

Westinghouse 2-phase induction motor marked "M-68". Metal plate reads: " The Westinghouse Electric Co. Pittsburgh, 271". Case has radial fins for heat dissipation. Connection is made through two binding posts on the base. An electrodynamic rotation motor designed by Nikola Tesla, without commutator or contact brushes. A series of field magnets are built of laminated sheet iron and wound with two sets of coils. Two alternating currents are sent through the field at the same time, one a 1/4 phase behind the other. References: Electrical World, vol. 12, 27 October 1888, pages 221-223. Westinghouse Engineer, January 1950, page 72.