Condition Monitoring Of Motors And Rectification

Condition Monitoring of Electric Motors:There are many reasons for bearing failure as well as winding failures. If we monitor bearings and windings take timely corrective actions, we can make sure flawless service from the motor. Among the motor failures, 60% of the failures are because of bearing failures30% are because of winding problems and remaining 10% are because of some other problems. The on-line NDT methods like vibration and ultrasound analysis eliminate the reasons causing bearing failure. Many times a simple bearing failure turns into a catastrophic failure of the motor. In that case, the stator gets rubbed with the rotor and hence it damages the stator core, rotor core, rotor winding and stator winding. Hence we can secure motor from catastrophic failure if we take care of the bearing. Windings can be monitored through off-line inspections and if we add preventive measures (overhauling of the windings) in it, we can secure the motors from anomalies and can get flawless performance of the motor. Types of Condition Monitoring of Motors:We can carry Condition Monitoring of Electric Motors both in on-line as well as off-line mode. The on-line methods are Vibration Analysis, Ultrasound Analysis and Thermography. The off-line methods are Winding Resistance Test, Inductance Test, Surge Comparison Test, Polarization Index Test, Insulation Resistance Test, High Voltage Test (for HT Motors), Tan Delta and Capacitance Test (for HT Motors only). The off-line test can be carried out only when the plant is taken under shutdown.