ABB ACS800 Serie Manuel D'installation page 20

TROUBLE CAUSE
Wrong rotation Wrong sequence of phases
direction
Motor overheats Overload
while running
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 vibrates 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
Scraping noise Fan rubbing end shield or fan
cover
Loose on bedplate
Noisy operation Air gap not uniform
Rotor unbalance
Hot bearings Bent or sprung shaft
Excessive belt pull
Pulleys too far away from shaft
shoulder
Pulley diameter too small
Misalignment
Insuffi cient grease
Deterioration of grease or
lubricant contaminated
Excess lubricant
Overloaded bearing
Broken ball or rough races
EN – 20
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 fi ts or bearing fi ts.
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 fi rst.
ABB/Low Voltage Motors/ Ex manual 01-2007