ABB MT Serie Manual De Instalación, Operación Y Mantenimiento página 13

TROUBLE
Motor overheats while
running underloaded
Motor vibrates
Scraping noise
Noisy operation
Hot bearings ball
ABB / Low Voltage Motors / Manual 12-2004
CAUSE
Overload
Frame or bracket vents may be
clogged with dirt and prevent proper
ventilation of motor
Motor may have one phase open
Grounded coil
Unbalanced terminal voltage
Motor misaligned
Weak support
Coupling out of balance
Driven equipment unbalanced
Defective bearings
Bearings not in line
Balancing weights shifted
Contradiction between balancing of
rotor and coupling (half key - full key)
Polyphase motor running single
phase
Excessive end play
Fan rubbing fan cover
Fan striking insulation
Motor loose on bedplate
Airgap not uniform
Rotor unbalance
Bent or sprung shaft
Excessive belt pull
Pulleys too far away
Pulley diameter too small
Misalignment
Insuffi cient grease
Deterioration of grease or lubricant
contaminated
Excess lubricant
Overloaded bearing
Broken ball or rough races
WHAT TO DO
Reduce load.
Open vent holes and check for a continuous
stream of air from the motor.
Check to make sure that all leads are well
connected.
Locate and repair.
Check for faulty leads, connections and
transformers.
Realign.
Strengthen base.
Balance coupling.
Rebalance driven equipment.
Replace bearings.
Line up properly.
Rebalance motor.
Rebalance coupling or motor.
Check for open circuit.
Adjust bearing or add shim.
Remove interference.
Clear fan.
Tighten holding bolts.
Check and correct bracket fi ts or bearing.
Rebalance.
Straighten or replace shaft.
Decrease belt tension.
Move pulley closer to motor bearing.
Use larger pulleys.
Correct by realignment of drive.
Maintain proper quality of grease in bearing.
Remove old grease, wash bearings thoroughly
in kerosene and replace with new grease.
Reduce quantity of grease, bearing should not
be more than 1/2 fi lled.
Check alignment, side and end thrust.
Replace bearing, fi rst clean housing thoroughly.
13 – GB