Effects of external yoke and clamping-plates on AC motor external field

This study focuses on the external flux in the vicinity of AC electrical rotating machines. The influence of the external housing, constituted of the external yoke and the clamping-plates, is studied with a finite-element modelling, an analytical model and experimental measurements. Two induction machines are analysed; the first is equipped of an external yoke made of cast iron, whereas the second is made of aluminium. Those machines have been instrumented with magnetic flux sensors placed each side of the flanges and each side of the external yoke border. The conclusions of this study have a double interest. On the one hand, they can be used to understand what the influence of the external housing in the flux transmission is. That allows using the external magnetic flux as information to diagnose the rotating machines. On the other hand, the study can help machine designers to define motors with a discreet magnetic signature.

[1]  Fabrice Morganti,et al.  Use of the External Magnetic Field for Induction Machine Leakage Inductance Distinction , 2010, IEEE Transactions on Magnetics.

[2]  H. Henao,et al.  A frequency-domain detection of stator winding faults in induction machines using an external flux sensor , 2002, Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344).

[3]  Mario Chiampi,et al.  Role of magnetic materials in power frequency shielding: numerical analysis and experiments , 2001 .

[4]  Daniel Roger,et al.  Attenuation of magnetic field components through an AC machine stator , 2008 .

[5]  Colin D. Simpson,et al.  Industrial Electronics , 1936, Nature.

[6]  H. Henao,et al.  Diagnosis of Broken Bar Fault in Induction Machines Using Discrete Wavelet Transform without Slip Estimation , 2007, 2007 IEEE Industry Applications Annual Meeting.

[7]  Gérard Meunier,et al.  Calculation of electrical machine magnetic stray fields , 2002 .

[8]  K. Komeza,et al.  EMI of large power systems: magnetic field calculation by substituting surface quantities for complex sources , 2007 .

[9]  Aldo Canova,et al.  Evaluation of different analytical and semi-analytical methods for the design of ELF magnetic field shields , 2002 .

[10]  Hubert Razik,et al.  On the Use of Slot Harmonics as a Potential Indicator of Rotor Bar Breakage in the Induction Machine , 2009, IEEE Transactions on Industrial Electronics.

[11]  Fabrice Morganti,et al.  Non Invasive Sensors for Monitoring the Efficiency of AC Electrical Rotating Machines , 2010, Sensors.

[12]  Shahin Hedayati Kia,et al.  A High-Resolution Frequency Estimation Method for Three-Phase Induction Machine Fault Detection , 2007, IEEE Transactions on Industrial Electronics.