Induction motors use shorted wire loops on a rotating armature and obtain theirtorque from currents induced in these loops by the changing magnetic fieldproduced in the stator (stationary) coils.
 | At the moment illustrated, the current in the stator coil is in the direction shown and increasing. The induced voltage in the coil shown drives current and results in a clockwise torque. Note that this simplified motor will turn once it is started in motion, but has no starting torque. Various techniques are used to produce some asymmetry in the fields to give the motor a starting torque.  |
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