In 1888, Tesla presented his paper " A New System for Alternating Current Motors and Transformers " to the AIEE that described three patented two-phase four-stator-pole motor types : one with a four-pole rotor forming a non-self-starting reluctance motor, another with a wound rotor forming a self-starting induction motor, and the third a true synchronous motor with separately excited DC supply to rotor winding.
