the interactions of the magnetic field and current as expressed by the given: Ibid where: =force =torque =radius of rotor rings =rotor bar Induction motor slip A stator magnetic field rotates at synchronous speed, Ibid where: = frequency = number of poles If = rotor speed, the slip, S for an induction motor is expressed as: mechanical speed of rotor, in terms of slip and synchronous speed: Relative speed of slip: Frequency of induced voltages and currents See also Armature (electrical engineering) - any "rotor" that carries some form of alternating current Balancing machine Commutator (electric) Electric motor Field coil Rotordynamics Stator References Electric motors