Effects of the Slot Harmonics on the Unbalanced Magnetic Pull in an Induction Motor With an Eccentric Rotor

The slotting of electrical rotating machines creates slot harmonics of the air-gap magnetic flux density. These slot harmonics are the source of a nonnegligible part of the unbalanced magnetic pull (UMP). This paper presents analytical justifications for the use of a numerical impulse method to calculate the effects of the slot harmonics on the UMP. It uses the method to show that the force components due to the slot harmonics cannot be reduced easily.