Induction Motor

             
  Gramme Dynamo                           Tesla's Induction Motor
  nationalmaglab.org                         teslasociety.com

While studying at the Austrian Polytechnic School for mechanical and electrical engineering, Tesla was introduced to a new Gramme dynamo that used direct current to function as both a motor and generator. Tesla believed that there was a better way to build the motor; that the sparking connections, called commutators, were not necessary. Tesla's professor, on the other hand, was of the belief that Tesla's idea was equivalent to building a perpetual motion machine. However, Tesla never gave up on on the idea.

While working in Budapest, at the age of 24, for the Central Telephone Exchange, inspiration struck Tesla. Two pairs of electromagnetic coils, energized with alternating current, create a magnetic field that induces an electric current in the rotor. This current creates its own magnetic field that tires to oppose the magnetic field created by the outer coils. As the result, the rotor turns.