MarelliMotori MXB-E 180 Serie Manual De Instalación, Funcionamiento Y Mantenimiento página 41

6.2 Bearing maintenance
The actual lifecycle of the bearings depends on several elements, and in particular:

on the grease life,

on the environment conditions and on the operating temperature,

on external loads and vibrations.
The bearings on the D side (coupling side) and on the N side (side opposite to the coupling) are of sealed type,
and the amount of grease they contain allows them to operate for a long time.
Under normal usage condition, the period in question is of about 30,000 hours for all the bearings.
In any case, when fully overhauling the unit, replace the bearings.
6.3 Disassembly operations for bearing replacement
BEFORE DISASSEMBLING THE GENERATOR FROM THE DRIVE MOTOR, MAKE SURE THAT THE
LATTER CANNOT BE STARTED.
Before disassembling the generator, please refer to the section views. Also check that the lifting means capacity
is appropriate for the weight of the components to be handled.
Also check that all handling safety measures have been taken.
The disassembly and re-assembly operations must be performed by specialised and qualified personnel; we
recommend that you contact a workshop authorised by the Marelli Service.
If deemed necessary, mark the components during disassembly, to be able to later reinstall them in the proper
position.
Never loosen or remove the tie rods fastening the generator supports.
WARNING!
Uncouple the generator from the drive motor, removing the fastener of the feet, of the union and of the coupling
device (SAE disc/joint). Disconnect the power cable terminals from the terminal panel.

Move the generator away from the motor using the eyebolts located on the generator. (The weight of
the generator is specified in the nameplate).
For dual-support generators:

Remove the joint from the shaft and remove the key from the axis protruding part.

Remove the plastic protections from the N side shield.

Turn the generator until it stands firmly upright using the eyebolt located on the union.

Remove the screws fastening the D side shield to the union.

Remove the shield.

Screw an M10 eyebolt on the protruding part of the axis and withdraw the rotor, taking care to hold the
frame in place.

Remove the O-Ring from its seat in the N side shield.
For single-support generators:

After moving the generator away from the drive motor, fasten the disc to the union using 2 appropriate
clamps, to ensure that the rotor doesn't accidentally slip out.

Remove the plastic protections from the N side shield.

Turn the generator until it stands firmly upright using the eyebolt located on the union.

Screw an M8 or M10 eyebolt (depending on the generator size) on the protruding part of the axis, then,
after removing the clamps, withdraw the rotor, taking care to hold the frame in place.

Remove the O-Ring from its seat in the N side shield.
For the disassembly of the bearings use an appropriate puller.
6.4 Re-assembly operations after bearing replacement
The installation of the bearings onto the shaft must be carried out with the utmost care, preferably after heating
the bearings to about 80 - 90°C.
The O-Ring must always be replaced whenever the rotor is disassembled.

Apply an uniform layer of paste LGAF 3E (BY SKF) on all the outer ring surface using a proper tool
(paintbrush or spatula). An excessive layer thickness could bring to difficulties during bearing mounting
on end shield.

Prepare the N-end shield without the O-Ring and apply an uniform layer of paste LGAF 3E (BY SKF)
on all the bearing arrangement surface. An excessive layer thickness could bring to difficulties during
bearing mounting on end shield.
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