An on-board system to diagnose faults in squirrel cage induction motors​

Principal Investigator: Dr. Aurobinda Routray

Co-researchers: Anik Samanta, Dr. Arunava Naha

• to develop a device to detect the presence and level of faults in a squirrel cage induction motor

• Identification of faults using a fault monitoring device can be beneficial to a lot of industries

There are different kinds of faults which can occur in an induction motor. They are

• stator fault

• rotor fault

• bearing fault

• eccentricity fault

Stator Faults

Stator faults mainly comprise the Inter-turn Short Circuit (ITSC) faults. (ITSC) occurs when a few turns from the same coil in the stator slot get short-circuited because of insulation degradation.

Rotor Faults

Single or multiple rotor bars or the end ring may break because of the uneven magnetic pull. The most likely locations of the breakage are the joints between the end ring and the rotor bars.

Bearing Faults

Bearing consists of three major parts: inner ring, outer ring and rolling elements. Due to fatigue, corrosion, improper lubrication installation defects, etc., small parts of the bearings may break loose.

Eccentricity Faults

In the presence of eccentricity faults, the air gap between the stator and the rotor of the induction motor does not remain uniform along the inner periphery of the stator. Eccentricity faults can be of three types

• static eccentricity: In the case of static eccentricity fault, the axis of rotation and the rotor axis coincide with each other, but they are different from the stator axis.

• dynamic eccentricity: In the case of dynamic eccentricity, the stator axis and the axis of rotation coincide with each other, but they are different from the rotor axis.

• mixed eccentricity: In the case of mixed eccentricity, all the three axes, stator axis, rotor axis and the axis of rotation are different from each other.