Flameproof motors | 17
- Close the bearing tightly with the top sight glass.
In case the standstill period is longer than 6
months:
- Repeat the procedures described above.
- Replace the desiccant (silica gel) into the
bearing each six months.
In case the standstill period is longer than 2 years:
- Dismantle the bearing;
- Preserve and store the bearing parts.
By using either a chain block or a
jack, raise the end of the rotor at
which the work is being done
aproximately 0.1 to 0.3mm so as to
remove the weight from the bottom
half of the bearing and not damage
the flameproof labyriths.
3.7.10. CONNECTION BOX
When the winding insulation resistance of the motor
is verified, the main terminal box and the auxilliary
terminal boxes must also be inspected, observing
the following aspects:
- The interior should be dry, cleaned and free of
any dust accumulation.
- The contact elements cannot present corrosion.
- The machined surfaces of explosion proof
terminal boxes with protection “d” which
functions as flamepath joints should be perfectly
clean, without any deformation, damage or
scratches. Before reassembling the covers of
these terminal boxes apply a corrosion inhibiting
grease (ex.: Polyrex EM or Molycote 33 or
Lumomoly PT/4) to avoid the corrosion of the
machined surfaces.
- The motors with protection “de” are equipped
with terminal boxes with protection “e” that
constructively can be the same used for
protection “d”. In this case, machined surfaces
don’t function as flamepath joints but it’s very
important to maintain them in good conditions
applying also a corrosion inhibiting grease (ex.:
Polyrex EM or Molycote 33 or Lumomoly PT/4)
to avoid the corrosion of the machined surfaces.
- The cables inlet should be correctly sealed.
- The cable entrances into the terminal boxes
must be done using certified cables glands with
the same, or higher, protection of the motor (Ex
d IIB, Ex d IIC, Ex e, Ex d I or Ex e I) indicated in
the motor nameplate.
If any of these items are not in proper condition, an
adequate maintenance should be performed and, if
necessary, the damaged parts should be replaced.
EX ATMOSPHERE INFORMATION
The use and assembling of the
appropriate cable glands is
responsibility of the motor installer.
3.7.11. INSPECTIONS AND RECORDS DURING
STORAGE
The stored motor must be inspected periodically
and inspection records must be filled.
The following points must be inspected:
- Physical damages;
- Cleanliness;
- Signs of water condensation;
- Protective coating conditions;
- Paint conditions;
- Signs of aggressive agents;
- Satisfactory operation of space heaters. It is
recommended that a signaling or alarm system
be installed in the location in order to detect
power interruption on the space heaters;
- Record the ambient temperature and relative
humidity around the motor, the winding
temperature (using RTDs), the insulation
resistance and the polarization index;
- Record vibrations, in horizontal, vertical and
axial directions at Drive End and Non Drive End
sides to guarantee that motor is not being
subjected to harmfull values;
- Storage site, so that it complies with the criteria
described in sub-section 3.7.3.
3.7.12. PREPARATION FOR SERVICE AFTER
LONG TERM STORAGE
3.7.12.1 CLEANING
- The machine interior and exterior should be free
of oil, water, dust and dirt.
- Remove the corrosion inhibitor of the exposed
surfaces with a cloth soaked in petroleum based
solvent.
- Be sure that the bearings and cavities used to
lubrication are free of dirt and the plugs on the
holes are correctly sealed and tighten.
Oxidations and marks on the bearings seats and
shaft should be carefully removed.
- Be sure that the flameproof joints that were
exposed during storage are free of any
corrosion, scratches or deformations and are
properly protected against corrosion.
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