44 | Flameproof motors
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As a general rule, greases with the same thickner
type are compatible, but depending of the mixing
proportion, may be incompatible. Therefore, is not
recommended mixing different types of grease,
without first consulting the grease supplier and/or
WEG.
Same and basic oils can not be mixed as they will
not produce a homogeneous mixture. In this case,
either a hardening or a softening (or drop of the
resulting mixture melting point) can occur.
8.2.7. LUBRICATING INSTRUCTIONS
The lubrication system was designed to allow,
when regreasing, the removal of all grease from the
bearings races through a grease relief which at the
same time avoid the entry of dust or other
contaminants harmful to the bearing.
This grease relief also avoids injury to the bearings
from the already known problem of over-greasing.
It is advisable to relubricate while the motor is
running so as to allow the renewal of grease in the
bearings housing.
If this procedure is not possible due to existing
parts near to the nipple (pulleys, etc), which can be
harmful to the operator, the following procedure
should be followed:
- Inject about half the estimated amount of
grease and run the motor at full speed for
approximately one minute;
- Switch off the motor and inject the remaining
grease.
As a rule, motors should be greased with the motor
in operation. Otherwise, the grease, instead of
going through the bearing area, will penetrate into
the motor through the internal seal of the bearing
housing.
NOTE
Grease fittings and surrounding areas
must be clean before greasing the
motor in order to avoid entry of any
foreign bodies into the bearing.
For lubrication, use only a manual grease gun.
Figure 8-1 - Bearings and lubrication system
8.2.8. BEARING LUBRICATION STEPS
Remove the grease relief cover, if any;
Clean the area around the grease fitting
using a clean cotton fabric;
EX ATMOSPHERE INFORMATION
Be sure that the material used for the
cleaning operation does not create
dangerous static electricity buildup.
With the motor running, add the amount of
grease indicated on the motor nameplate;
Leave the motor running for 1 to 2 hours to
allow drain of the excess of grease. Replace
the grease relief fitting, if any;
During lubrication, increase in bearing
temperature may be noticed. However, after
one hour of operation, motor should achieve
normal operating temperature. See Figure
below.
Check bearing temperature to make sure
there has not been any major variation.
Figure 8-2 - Bearing temperature
5 min ... 60 min
5 K ... 20 K
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