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10. Faults, causes, remedy
10.1 General fault indications
The Sections 5 "Safety notes" and 11 "Service and Maintenance" must be observed.
Faults occurring during the warranty period which require repair of the gear unit may only be repaired
by employees of the Nidec Graessner service department.
If, after the warranty period, faults occur whose causes cannot be clearly identified,
the Nidec Graessner service department must be contacted.
10.2 Possible faults
Faults
Causes
Remedy
Changed operating noise
Damage to gearings
Bearing play is increased.
Bearing is defective
Check geared components; if necessary,
replace any damaged components, adjust
bearing play, contact service department
Replace defective bearing, contact service
department
Increased temperature at
the bearing points
Oil level in the housing is too low or too
high
Oil is too old
Bearing is defective
Check oil level at room temperature,
if necessary replenish or drain oil.
Check when the last oil change has been
carried out. If necessary, change the oil
Check bearing condition; replace,
if necessary; contact service department
Gear unit is oily on the out-
side
Insufficient sealing of the bearing flanges
and gear unit covers
Seal bearing flanges and gear unit covers
Oil leak at the ventilation
filter
Oil foams
Oil level in the gear unit is too high
Incorrect execution of the ventilation
See fault "Oil foams in gear unit"
Decrease oil level in gear unit to the
pre-specified level
Prevent any direct oil injection by attaching
suitable extensions or angle pieces
Oil leaks from gear unit
Insufficient sealing of the bearing flanges
and gear unit covers
Radial shaft seal rings are defective
Check seals, replace if necessary
Check radial shaft seal rings, replace
if necessary.
Oil foams in gear unit
Water in oil
Oil too old (De-foaming agent used up).
Unsuitable oils mixed up
Examine oil condition for water ingress by
means of a test tube sample.
Have the oil sample analysed, change oil.
Examine oil, change oil
Examine oil, change oil
Water in oil
Water condensates in the gear unit by
external climatic conditions, sun, wind,
cold: Ambient temperatures change a
great deal.
Protect gear unit against temperature
influences
Increased operating tem-
perature
Oil level in the gear unit is too high.
Oil is too old
Oil is highly contaminated
Check oil level Correct if necessary.
Check when the most recent oil change was
carried out, change oil
Have the oil sample analysed, change oil.
