Stray flux analysis

This research line is aimed to investigate and develop new techniques based on the analysis of the stray flux that are valid for every operation regime of the motor. Over recent decades, it has been proven that the analysis of the external magnetic field in the surroundings of an electric motor can provide very useful information for the diagnosis of many faults. In this context, many authors proposed the study of the stray flux to diagnose several failures in electric motors. Nonetheless, most of the available methods relying on flux analysis are based on the analysis of this quantity under steady-state operation.

In this context, the research team opened a new research line consisting on the analysis of the stray flux under any operation regime of the motor (including transient regimes). The idea was to extrapolate the knowledge and experience that the team has in the transient current analysis area to the analysis of stray flux signals under transient operation.

In this line, the group has obtained very interesting results which have yielded different publications both in reputed journals and Conferences. It has been shown that the time-frequency analyses of the electromotive force (emf) signals induced by the stray flux in external sensors attached to the motor frame lead very reliable indicators for the diagnosis, even avoiding some drawbacks of classical methods. The team has successfully applied the methods to the detection of rotor damages, eccentricities and misalignments, among other faults.

The ongoing research in this area is oriented toward the following objectives:

- Determination of the best sensor position and characterization of the evolutions at each position.

- Optimization and improvement of techniques based on transient analysis of the stray flux.

- Integration of different flux measurements in a single sensor.

- Automation of the diagnosis process based on stray flux measurement.

- Extension to other faults.

- Extension to different machines (PM, synchronous motors…).

The interest of academia and industry in this investigation is increasing due to the advantages of this technique (non invasive nature, simplicity, available sensor features) and on the fact that many manufacturers are incorporating flux sensors embedded in their motors.

Representative team projects: DIAGFLU, SISTINMOT, MOTORTECH

Most relevant publications:

1. Juan A. Ramirez-Nunez ; Jose A. Antonino-Daviu ; Vicente Climente-Alarcón ; Alfredo Quijano-López ; Hubert Razik ; Roque A. Osornio-Rios; Rene de J. Romero-Troncoso (2018), "Evaluation of the Detectability of Electromechanical Faults in Induction Motors Via Transient Analysis of the Stray Flux," in IEEE Transactions on Industry Applications, vol. 54, no. 5, pp. 4324-4332, Sept.-Oct. 2018.

2. Israel Zamudio-Ramirez; Jose A. Antonino-Daviu; Roque A. Osornio-Rios; Rene J. Romero-Troncoso; Hubert Razik. (2020) Detection of Winding Asymmetries in Wound-Rotor Induction Motors via Transient Analysis of the External Magnetic Field. IEEE Transactions on Industrial Electronics, vol. 67, no. 6, pp. 5050-5059, June 2020.

3. Israel Zamudio-Ramírez, Juan Angel Ramirez-Núñez, Jose Antonino-Daviu, Roque A. Osornio-Rios, Alfredo Quijano-Lopez, Hubert Razik, Rene de Jesus Romero-Troncoso, (2020) "Automatic Diagnosis of Electromechanical Faults in Induction Motors Based on the Transient Analysis of the Stray Flux via MUSIC Methods," in IEEE Transactions on Industry Applications, vol. 56, no. 4, pp. 3604-3613, July-Aug. 2020.

4. M. Iglesias-Martinez, J. Antonino-Daviu, P. Fernández de Córdoba, J.A. Conejero (2019), “Rotor Fault Detection in Induction Motors Based on Time-Frequency Analysis Using the Bispectrum and the Autocovariance of Stray Flux Signals”, Energies (12)597-1 - 597-16. 2019.

5. Panagiotis A. Panagiotou; Ioannis Arvanitakis; Neophytos Lophitis; Jose A. Antonino-Daviu; Konstantinos N. Gyftakis. (2019) A New Approach for Broken Rotor Bar Detection in Induction Motors Using Frequency Extraction in Stray Flux Signals. IEEE Transactions on Industry Applications, 4 (55), 3501 - 3511.

6. Miguel E. Iglesias-Martínez; Pedro Fernández de Córdoba; Jose A. Antonino-Daviu; J. Alberto Conejero . (2019) Detection of Nonadjacent Rotor Faults in Induction Motors via Spectral Subtraction and Autocorrelation of Stray Flux Signals. IEEE Transactions on Industry Applications, 5 (55), 4585 - 4594.