Some common faults in MRL PM Motors and the associated effects on the application.
The launch in 2010 of NDC's ServoLab, a dedicated facility undertaking the repair, service, re-building and function testing of permanent magnet motors has seen an influx of faulty motors from MRL lift applications. A member of our Motor Services Team discusses some of the more common issues we have encountered and their likely impact on the lift application.
Worn and faulty bearings can be a major hindrance in the smooth running of a permanent magnet motor as they can hamper the movement of the lift. Faulty bearings can cause a large amount of current to flow through the motor windings due to the restricted movement of the rotor which in due course damages the windings.
Damp and Dirty windings:
Over a period of time the motor windings tend to become dirty or even damp. This results in the reduction of the torque produced by the motor which effects the working of the lift under full load. Damp windings at times are a major cause of short circuit in the wiring circuit which causes damage to the drive system.
Faulty Feedback Device:
A faulty feedback device is considered to be one of the major faults in the permanent magnet motor which could result in loss of motor control and which could mean a loss of control over the lift movement.
Worn Bearing Housings:
A motor with worn bearing housings causes its rotation to be uneven and unbalanced which exerts a lot more pressure on the motor windings and causes the lift drive to trip very often. An unbalanced rotation of the motor can also damage the feedback unit of the motor.
A motor that has a worn or damaged shaft can affect its ability to effectively work in the lift application due to the fact that the worn shaft would not hold the lift pulley as well as it should and could cause the lift to have uneven movement which could result in various drive and sensor errors.