50 | Flameproof motors
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FORCED
LUBRICATION
(EXTERNAL)
BEARINGS
The change of the oil in the bearings should be
made every
20,000 working hours
, or whenever
the
lubricant
present
alterations
in
its
characteristics. The viscosity and pH of the oil
should be periodically verified.
NOTE
Oil level must be checked daily which
must be kept approximately at the
center of the oil level sight glass.
The bearing must be filled with the prescribed type
of oil through the oil port after removing the pipe
plug.
All holes and threads not used must be closed by
pipe plugs. Also check all connections for oil leaks.
Filling the bearing with lubricant beyond the middle
of the oil sight glass (II) does not impair the function
of the bearing, but there is a possibility that excess
oil may leak out through the shaft seals.
ATTENTION
The
cares
taken
with
bearing
lubrication will determine the life for
such bearings as well as the
assurance of motor operation.
For this reason, it is essential to follow
these recommendations:
- The oil selected must have a
viscosity suitable for the bearing
operating temperature. This must
be checked during eventual oil
change
or
during
periodical
maintenances.
- If the bearing is filled with oil bellow
the required oil level, or if the oil
level is not checked periodically,
insufficient lubrication may lead to
damage to the bearing liner. The
minimum oil level is reached when
the oil can just be seen in the oil
sight glass when the machine is not
in operation.
8.2.10.8 SHAFT SEALS
The two halves of the floating labyrinth seal are
held together by a garter spring. They must be
inserted into the groove of the carrier ring in such a
way that the stop pin is always in the corresponding
recess in the upper half of the housing or carrier
ring. Incorrect installation destroys the seal.
The seal is to be carefully cleaned and coated with
a non-hardening sealing compound on the faces in
contact with the grooves. The drain holes in the
lower part of the seal must be clean and remove
obstruction. When installing the bottom half of the
seal, press it lightly against the underside of the
shaft.
8.2.10.9 OPERATION
The operation of motors fitted with sleeve bearings
is similar to motors fitted with roller bearings.
It is recommended that the oil circulating system is
carefully accompanied during the first hours of
operation.
Before the start-up, check the following:
- If the oil used has been prescribed accordingly.
- Characteristics of the lubricating oil.
- Oil level.
- Alarm and tripping off temperatures set for the
bearings.
During the first start-up, check for vibrations or
noises. In case bearing operation is not quiet and
not uniform, motor should be stopped.
Motor must operate for several hours until the
bearing temperature is fixed within the limits
previously indicated. If a temperature overheating
occurs, motor must be stopped immediately and
the temperatures detectors checked.
When bearing operating temperature is reached
check for any oil leakage by the plugs joints or by
the shaft end.
AIR GAP CHECKING
As an optional feature, W22Xd motors can have
access entries to perform air gap checking.
Measure the air gap in all rotor poles in four
equidistant points of the stator (e.g. 45º, 135º, 210º
and 330º).
The difference between the air gap measured in
two points diametrically opposed must be less than
10% of the average air gap.
PARTIAL
DISCHARGE
MONITORING
In case of motors equipped with partial discharge
monitoring, the terminal box contains the BNC
jacks/terminal board for sampling with Iris portable
equipment TGA-B (not in WEG scope of supply)
indicated in the identification plate with the
following design: