Flux distributions in three-phase induction motor with disconnection problem

The characteristics of a three-phase induction motor with a disconnection problem are measured by using a practical 0.5-kW three-phase, four-pole model in which the stator connection can be selected arbitrarily. The change of the load characteristics and of the flux distribution for differences in the stator connection is clarified quantitatively to obtain the necessary information in the diagnosis of the disconnection problem. Under the normal condition of three kinds of star connection, the distortion factors of the flux waveforms are under 2.5%. In the case of disconnection, these values are increased in almost all search coils. When the connection is series-circuit construction, the malfunctioning point can be related to the change of the maximum flux density of the distortion factor