Mechanical
Faults and remedies
Fault
Possible cause
Remedy
Rough running
When coupled, machine runs
unevenly or with strong vibration,
with no fault when uncoupled
Fault in power transmission
components or in driven equipment
Check power transmission, drive
components and alignment
Settling of foundation
Restore correct foundation level,
realign machine set
Transmission or driven equipment
badly balanced
Rebalance
Machine runs roughly when
uncoupled
Bearing damage
Holding-down bolts loose
Refer to bearing faults below
Tighten and lock
Post-mounted coupling adversely
affecting rotor balance
Rebalance rotor with coupling
Damage to rolling bearings
Overheating immediately after
starting or regreasing
Too much grease filled
Fill and press in only the prescribed
amount of grease (See rating plate).
Overheating automatically disappears
after some time
Overheating after long period of
operation
Bearing cover seals rubbing
Remachine bearing cover, replace
damaged seals
Scraping, rubbing or knocking
noises in bearing
Change bearing (cause to be
determined by specialists)
Whistling sounds in grease
lubricated bearings
Bearing is dry
Inject grease
Damage on bearing cage
Replace bearing
Formation of indentations when
machine stationary
Vibrations being transferred to
bearings from external source
Isolate motor from external vibration or
keep rotor turning continuously
Formation of indentations when
machine in operation
Electric current flowing through the
bearing
Consult ABB
