| dc.description.abstract | The induction machine in the motor operation is one of the most used electrical machines in
the petroleum, mining and steel industries. For this reason, the necessity of maintaining a
continuous operation is indispensable to avoid enormous economic losses. Therefore, online
and off-line diagnostic techniques have been developed in order to detect incipient
faults in an early stage.
A common fault which is presented in this type of rotating machines is the eccentricity, and
it is mainly caused by wear and failure of bearings, unbalance of the rotor or misalignment.
Besides, if eccentricity is not diagnosed properly it can cause several failures such as
friction between stator and rotor, and as a consequence the destruction of the machine.
In this work, an analysis considering the effect of eccentricity in the machine inductances is
done as well as the impact on its dynamic behavior under no-load starting performance and
during a 3-phase fault at the machine terminals.
Mathematical models in different reference frames are presented. The induction machine
abc reference frame model is used since it takes into account the inductances rotor position
dependence. Also, the modified machine technique is proposed to include the external
impedance in the induction motor model and the Winding Function Method is employed to
calculate these inductances.
In order to consider the effects of different sorts of eccentricity, an expression for the air
gap distribution is used, which can include static, dynamic and the combination of both
eccentricities. A program in Fortran 90 is developed to simulate the dynamic of the
machine taking into account the different conditions mentioned above. | |
