Method of diagnosing a broken bar fault in an induction motor

摘要

A method for diagnosing induction motor broken bar faults using the resultant magnetic field pendulous oscillation phenomenon is disclosed. Broken bar faults cause the resultant magnetic field of an induction motor to possess a pendulous oscillation modulating its inherent rotation at synchronous speed, and the range of this angular pendulous oscillation, referred to as the swing angle, increases with an increase in the number of broken bars. The angular pendulous oscillation is determined by calculating the space vectors derived from motor terminal voltages and currents. The variation in the angular difference between these two space vectors versus time is used to observe the resultant magnetic field's pendulous oscillation, and thus provide on-line rotor fault diagnostics.