Analysis of electromagnetic and thermal fields in an induction motor with broken-bars fault

In this paper, the time-stepping coupled finite element models of a squirrel-cage induction motor in healthy and faulty states are developed. The stator current, rotor bar current and the end-ring current are calculated using the model respectively when the motor works at healthy state, one-broken-bar fault and adjacent two-broken-bar fault states. Aiming at the difficulty of determining the forced boundary condition, when traditionally solving the electrical machine stator or rotor temperature field, a two-dimensional model and a finite element model of a stator-rotor coupled temperature field over the whole cross section of a squirrel-cage induction motor are developed. The steady stator-rotor coupled temperature fields of the motor under rated load at the above three conditions are calculated respectively. The temperature rises of the motor operating at three conditions are compared and the influence of the number of broken bars on the motor temperature field is analyzed. The temperature field model can be applied to the temperature field analysis of other induction motors without axial cooling whether they are with healthy rotors or broken bars. The validity of models and the correctness of the calculated values are verified by experimental results derived from a prototype motor. From the variations of the motor electromagnetic field and temperature field, some valuable idea can be proposed to the broken bars fault diagnosis.

[1]  F. Filippetti,et al.  Quantitative evaluation of induction motor broken bars by means of electrical signature analysis , 2000, Conference Record of the 2000 IEEE Industry Applications Conference. Thirty-Fifth IAS Annual Meeting and World Conference on Industrial Applications of Electrical Energy (Cat. No.00CH37129).

[2]  Andrea Cavagnino,et al.  Solving the more difficult aspects of electric motor thermal analysis in small and medium size industrial induction motors , 2005 .

[3]  Li Weili,et al.  Finite Element Analysis of Field Distribution and Characteristic Performance of Squirrel Cage Induction Motor with Broken Bars , 2006, 2006 12th Biennial IEEE Conference on Electromagnetic Field Computation.

[4]  V. Hatziathanassiou,et al.  Thermal analysis of an electrical machine taking into account the iron losses and the deep-bar effect , 1999 .

[5]  D. Rodger,et al.  Coupled electromagnetic-thermal modeling of electrical machines , 2003 .

[6]  Chang-Eob Kim,et al.  The fault diagnosis of rotor bars in squirrel cage induction motors by time-stepping finite element method , 1997 .

[7]  G. Barakat,et al.  Comparison of modelling methods and of diagnostic of asynchronous motor in case of defects , 2004, 9th IEEE International Power Electronics Congress, 2004. CIEP 2004.

[8]  D. Trichet,et al.  A statistical approach of temperature calculation in electrical machines , 2000 .

[9]  A. Boglietti,et al.  Solving the more difficult aspects of electric motor thermal analysis in small and medium size industrial induction motors , 2005, IEEE Transactions on Energy Conversion.

[10]  A. Benchaib,et al.  Detection of broken bars in induction motors using an extended Kalman filter for rotor resistance sensorless estimation , 2000 .

[11]  J. Lang,et al.  Detection of broken rotor bars in induction motors using state and parameter estimation , 1989, Conference Record of the IEEE Industry Applications Society Annual Meeting,.

[12]  V. Hatziathanassiou,et al.  Electrical-thermal coupled calculation of an asynchronous machine , 1994 .

[13]  Nelson Sadowski,et al.  A thermal analysis of induction motors using a weak coupled modeling , 1997 .

[14]  B. Mirafzal,et al.  Induction machine broken-bar fault diagnosis using the rotor magnetic field space-vector orientation , 2004, IEEE Transactions on Industry Applications.

[15]  W. T. Thomson,et al.  Current signature analysis to detect induction motor faults , 2001 .

[16]  S. L. Ho,et al.  Analysis of Indirect Temperature-Rise Tests of Induction Machines Using Time-Stepping Finite Element Method , 2001, IEEE Power Engineering Review.

[17]  Behrooz Mirafzal,et al.  Induction machine broken-bar fault diagnosis using the rotor magnetic field space-vector orientation , 2004 .