Faults And Mechanical - ABB DC Machines DMI Operating And Maintenance Instructions Manual

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