Fault Detection in Magnetic Wedges of Induction Motor

G. R. BOSSIO; P. M. DE LA BARRERA; J. M. BOSSIO; C. VERUCCHI; R. LEIDHOLD

Buzios

Simposio; The 24th IEEE International Symposium on Industrial Electronics (ISIE 2015); 2015

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

In high power electric motors it is common to use open slots to facilitate the assembly of the coils. Open slots introduce harmonics in the magnetomotive force distribution over the air gap, resulting in additional losses and parasitic torques. In order to reduce these effects, wedges of magnetic material are used. These wedges are prone to apartial or total detachment, which in turn may result in other failures. In this paper a strategy to detect faults in magnetic wedges is presented. This strategy consists of the injection of a zero sequence voltage signal of high frequency. The resulting currents are highly dependent on the magnetic irregularities both the rotor and stator and thus sensitive to asymmetries produced by faults in the wedges. In this way, it is possible to detect and quantify wedges faults without the need to disassemble or remove the IM from the production line. The proposed strategy is applicable offline and required only disconnect the motor of the power supply. Laboratory experimental results are presented to validate the proposal.