Siemens 1LA8 Series Operating Instructions Manual page 21

Mechanical faults
Fault table, mechanical causes
Mechanical fault characteristics
↓ rubbing/grinding noise
↓ high temperature rise
↓ radial vibrations
↓ axial vibrations
Possible causes of fault
x Rotating parts rubbing/grinding
x Reduced air supply, fan possible running
in the incorrect direction of rotation
x Rotor not balanced
x Rotor out of true, shaft bent
x x Poor alignment
x Coupled motor not balanced
x Shocks from coupled motor
x x Imbalance originating from gearing
x x Resonance of the overall system comprising
motor and foundation
x x Changes in foundation
(1) Apart from elimination the cause of the fault (as described under "Remedial measures"), you must also rectify any damage
the motor may have suffered.
(2) Take any possible changes due to a rise in temperature into account.
Overview - Mechanical faults
Remedial measures
Determine cause and adjust parts
Check airways, clean motor
Decouple rotor and rebalance
Consult Siemens
Align motor unit, check coupling
Rebalance motor coupled up
Check motor coupled up
Adjust/repair gearing
After consultation, reinforce foundation
Determine cause of changes and
eliminate; realign motor
1)
2)
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