ABB M2A Manual De Instalación E Usuario página 20

TROUBLE
Wrong rotation
direction
Motor overheats
while running
Motor vibrates
Scraping noise
Noisy operation
Hot bearings
20 – EN ABB Motors and Generators | Low voltage Ex motor manual 01-2007
CAUSE
Wrong sequence of phases
Overload
Frame or ventilation openings may
be full of 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 end shield or fan cover
Loose on bedplate
Air gap not uniform
Rotor unbalance
Bent or sprung shaft
Excessive belt pull
Pulleys too far away from shaft
shoulder
Pulley diameter too small
Misalignment
Insufficient grease
Deterioration of grease or lubricant
contaminated
Excess lubricant
Overloaded bearing
Broken ball or rough races
WHAT TO DO
Reverse connections at motor or at switchboard.
Reduce load.
Open vent holes and check for a continuous stream of
air from the motor.
Check to make sure that all leads and cables are well
connected.
Motor must be rewound.
Check for faulty leads, connections and transformers.
Realign.
Strengthen base.
Balance coupling.
Rebalance driven equipment.
Replace bearings.
Repair motor.
Rebalance rotor.
Rebalance coupling or rotor.
Check for open circuit.
Adjust bearing or add shim.
Correct fan mounting.
Tighten holding bolts.
Check and correct end shield fits or bearing fits.
Rebalance rotor.
Straighten or replace shaft.
Decrease belt tension.
Move pulley closer to motor bearing.
Use larger pulleys.
Correct by realignment of the drive.
Maintain proper quality and amount 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 half full.
Check alignment, side and end thrust.
Replace bearing, clean housing thoroughly first.