Forces and fields in a current-carrying conductor
(a) Field produced by a current-carrying conductor in a slot.
(b) Air-gap field due to stator excitation and no current;symmetrical slot field.
(c) Asymmetrical field due to combined action of conductor current and stator excitation. Force is mainly exerted on the rotor iron core and not on the conductor.
(d) Force on a current-carrying conductor of lenght l in a magnetic field.
(e) Voltage induced in a conductor due to its motion through an external magnetic field (flux-cutting rule).