Removal And Replacement Of Components And Component Assemblies; Replacing The Bearings; Removal Of The Main Rotor; Replacing The Fan - Sincro SK160 Série Manuel D'utilisation Et De Maintenance

7.2 Removal and replacement of components
and component assemblies
The screws tightening torques for all reassembling
procedures are reported in the table of paragraph
6.2.3.

7.2.1 Replacing the bearings

Removal of the NDE bearing
• Unscrew the 4 nuts that fasten the back shield
to the housing.
• Disconnect the black and red wires from the AVR
board.
• Hammer the shield evenly until it comes away
from the rotor.
• Remove the snap ring.
• Remove the bearing using a standard extractor.
• Take the new bearing and heat it so its diameter dilates
before sliding it into position on the shaft.
• Replace the snap ring.
• Position the shield remembering to insert the snap
ring and fit the screws leaving them loose.
• Hammer the shield evenly until the bearing and section
of housing are in place.
• Tighten the nuts on the shield.
Reassembly of bearings
Reassembly of the bearing should be made in reverse
order of the operation described above taking in the
account the following cautions:
• Before fitting the bearing, ensure that the coupling
surfaces both on the bearing and shaft has no signs
of wear;
• Heat the bearing to approximately 80° C before fitting
it onto the shaft.
In case of regreasable bearing, follow the
procedure as described above, taking
into account to place back additional
mechanical parts used for bearing
lubrication in the same position like they
IMPORTANT!
were prior to dismounting. Apply the
quantity and type of grease as indicated
on the generator nameplate.

7.2.2 Removal of the main rotor

• Turn the rotor in position that the poles centerline is
in vertical position;
• Dismount the shields (NDE and DE) from the
generators as previously described;
• Using appropriately sized belt, support the DE side
with it and carefully start with tracking the rotor out
of the stator. As rotor come out of the stator, change
the position of the belt till the moment when it's
approximately on the gravity center of the rotor. During
this process, it's necessary to support the NDE end of
the rotor to guide the rotor precisely out of the stator to
avoid any damages of the stator or the rotor winding.
Reassembly
Reassembly of the rotor should be made in reverse
order of the operation described above taking in the
account the following cautions:
• in case that the any part of the rotor is changed, the
complete rotor must be re-balanced;
• in case of single bearing alternators, check if the
coupling discs are damaged.
7.2.3 Replacing the rotating diode bridge
• Remove the shield NDE, as 7.2.1
26
• The replacement of the diode bridge can also be made
without disassembling the NDE bearing, dismantling
the bearing however makes the operation easier.
• Remove the 3-way connector and the two fast-on.
• Loosen the lock screw and remove the diode bridge
To replace the diode bridge, proceed backwards:
• Fix the bridge with the locking screw and thread lock
• Restore the original links, respecting the polarity
• Replace the bearing shield and protective grid

7.2.4 Replacing the fan

• Uncouple the alternator from the drive motor
• Remove the shield DE side (in the case of mounting
IMB34)
• The fan is locked on the shaft through a key(1). Loose
the screw (2), without removing it, and then hit the
screw head with a hammer. This will allow the tongue
to move inside the angle seat, freeing the fan.
• Before removing the fan, mark the location of the
washers (mounted on the fan itself) used for balancing
• Then remove the screw and remove the fan
To replace the fan proceed backwards:
• Place the shaft key (1) in the key seat
• Insert the fan (by hand, or with the help of a rubber
hammer)
• Insert the screw (2), screw it into the tab (with thread
lock) and tighten it following the torque values shown
in paragraph 6.2.4
• Replace the balancing washers in their original
position (make sure that they are locked)
7.2.5 Changing rotor exciter
• Remove the shield NDE, as 7.2.1
• Remove the bearing NDE
• Disconnect and remove the rotating diode bridge
(see 7.2.3)
• The exciter rotor is locked to the shaft through a key
(1). Loose the lock screw (2), without removing it,
and then hit the screw head with a hammer. This will
allow the key to move inside the key seat, in order
to free the exciter rotor.
• Remove the screw and remove the exciter rotor.
To replace the exciter rotor work backwards:
• - Place the key (1) in its seat
• - Insert the cables of the main rotor in the exciter rotor
• Insert the exciter rotor (by hand, or with the help of a
rubber hammer)
• Insert the screw (2), screw it into the tab (with thread
lock) and tighten it following the torque values shown
in paragraph 6.2.4
• Reconnect the diode bridge observing the polarities
• Replace the bearing shield and protective grid.