Original Tesla induction motor, 1887-1888.
© Science Museum / Science & Society Picture Library
Nikola Tesla (1856-1943), naturalised American physicist and electrical engineer, was born in Croatia to Serbian parents. Tesla made the first practical induction motors. He made this working model to illustrate the claims of his patents. The induction motor has since become the most widely used form of electric motor because it is simple and robust. It has no electrical contacts to the rotor. Instead, it is what is known as a 'two-phase machine'; that is, it uses two alternating currents to produce the rotating magnetic field which makes the rotor turn. The induction motor was a major factor in the adoption of alternating current (ac) electricity supplies.