The effect of strong parasitic synchronous and asynchronous torques in induction machine with rotor eccentricity

Parasitic torque harmonics and stator current harmonics to rotational speed of the asynchronous motor are presented in this paper. To calculate these relationships a 2.5D finite element model has been used. The rotor bar skew has been simulated with the division of the electric machine into so called elementary machines having straight, but shifted against each other, rotor bars. The obtained results on both 2D and 3D graphs are presented to the rotational speed of the electric motor. Parameters for each particular harmonics have been found with these graphs. These graphs help to identify the origins of these harmonics as the co-action of the MMF of the stator current and the magnetic induction from the rotor in the airgap. Particular attention has been payed to how iron saturation influences these harmonics. The harmonics under study (in quantity of 18) has been taken under consideration, because they exhibited their presence in the above mentioned graphs as the functions of speed. Their origin has been also indicated on the graphs made as an extension of the Kluszczynski analytic/graphic diagrams.