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LV Motors / Ex-motors instructions 99-09
TROUBLE
CAUSE
WHAT TO DO
Motor overheats while
Overload
Reduce load.
running underloaded
Frame or bracket vents may be
Open vent holes and check for a continuous
clogged with dirt and prevent proper stream of air from the motor.
ventilation of motor
Motor may have one phase open
Check to make sure that all leads are well
connected.
Grounded coil
Locate and repair.
Unbalanced terminal voltage
Check for faulty leads, connections and
transformers.
Motor vibrates
Motor misaligned
Realign.
Weak support
Strengthen base.
Coupling out of balance
Balance coupling.
Driven equipment unbalanced
Rebalance driven equipment.
Defective bearings
Replace bearings.
Bearings not in line
Line up properly.
Balancing weights shifted
Rebalance motor.
Contradiction between balancing of
Rebalance coupling or motor
rotor and coupling (half key - full key)
Polyphase motor running single
Check for open circuit.
phase
Excessive end play
Adjust bearing or add shim.
Scraping noise
Fan rubbing air shield
Remove interference.
Fan striking insulation
Clear fan.
Loose on bedplate
Tighten holding bolts.
Noisy operation
Airgap not uniform
Check and correct bracket fits or bearing.
Rotor unbalance
Rebalance.
Hot bearings general
Bent or sprung shaft
Straighten or replace shaft.
Excessive belt pull
Decrease belt tension.
Pulleys too far away from shaft
Move pulley closer to motor bearing.
shoulder
Pulley diameter too small
Use larger pulleys.
Misalignment
Correct by realignment of drive.
Hot bearings ball
Insufficient grease
Maintain proper quality of grease in bearing.
Deterioration of grease or lubricant
Remove old grease, wash bearings thoroughly in
contaminated
kerosene and replace with new grease.
Excess lubricant
Reduce quantity of grease, bearing should not be
more than 1/2 filled.
Overloaded bearing
Check alignment, side and end thrust.
Broken ball or rough races
Replace bearing, first clean housing thoroughly.
