field 0 rpmrotor 0 rpmturns the field has gained on the rotor 0.00
Field pointing out of a tooth, or bar current one wayThe other wayThe shaftThree-phase current in the stator makes a magnetic field that sweeps around the motor: watch the red and blue band circle the teeth. On a 50 Hz supply this 2-pole motor's field turns at 3,000 rpm. Nothing is connected to the rotor. Its aluminium bars only carry current because the field slips past them, so the rotor always runs a little slower than the field, here 6% slower at full load. The curve below shows torque against speed: more load means more slip, up to the breakdown peak.