Abstract
A slight change in time phase shift between currents in
adjacent rotor end ring segments directly affects the
characteristics of the airgap torque in a squirrel cage induction
machine (SCIM). On the other hand the rotor slot geometrical
permeance has a strong impact on the rotor bar leakage
inductance. This paper deals with effect of different rotor bar
types (geometrical shapes) when a SCIM operates under healthy
and broken rotor bars condition. The three phase squirrel cage
induction machine is designed and modelled using two
dimension (2D) finite Element Model (FEM). Static and dynamic
analysis are performed in order to determine the target
performance indexes such as transient torque, steady state
torque, torque ripple, air-gap flux density, power factor and
efficiency. The Finite Element Analysis (FEA) results evidence
that the rotor bar shape can be optimized, such that the SCIM is
yet to produce good performance when the phase shift between
neighbouring bars e.m.f is changed due to rotor bar breakage.