Sheet No.
3AAM101049 E
Rev. B 01.2023
Page 3 of 4
Instruction, operation and maintenance instructions
High voltage flameproof motors for explosive atmosphere
AMD Rg 355-400-450-500
Vertical motors with rolling bearings – Assembly and
disassembly instructions
Grease lubricated rolling bearings
Issued by: MOLM
W
e
reserve
a
ll
rig
ht
s i
n t
his
do
cument an
d in t
he
inf
orm
at
ion
con
tai
n
e
d
the
rein.
R
ep
ro
duct
ion
,
use of
disclos
u
re
t
o t
h
ird
pa
rti
es wit
ho
ut
expr
ess
au
th
or
ity
is
s
tric
tly
for
bidden.
Important!
The explosion-proof motors are only to be
serviced by trained, certified personnel,
following the opportune instructions and
preferably under the supervision of an
Service
organization.
The
maintenance
operations are to conform to the requirements
specified in the EN/IEC Standards 60079-17
and 60079-19.
Motor disassembly
The following sequence of operations applies to
the normal maintenance jobs that could be
required during the course of general overhauls.
It is suggested to also consult the disassembly
instructions
for
horizontal
motors
(Sheet
3AAM101047) for further details with regard to
safety and the precautions o be taken during
certain stages.
Disconnect and physically separate all the
main power supply cables and monitoring
units from the boxes as well as the ground
connections.
Dismantle all the accessories on the top part
of the motor and the protection roof, to make
the lifting easier.
Loosen and remove the bolts fastening to the
base plate and the location pins (if present)
and uncouple the motor from the driven
machine tool.
Attach the motor to the lifting equipment with
eye bolts, provided on the casing.
Lock the end of the shaft with the anti-rotation
locking device.
With extreme care, remove the motor from the
base-plate Arrange it with the axis horizontal,
using a suitable fixed block as overturning
pivot. Rest the casing on wooden blocks. The
main terminal box is to be positioned upwards.
Dismantle the ventilation cap (08) and remove
the external fan (06) loosening the hub locking
screws.
Remove the shaft anti-rotation lock.
Dismantle the coupling joint to the driven
machine from the end of the shaft (see
3AAM101031). If the motor has joints at both
ends, remove both joints.
Remove the fastening split rings (10) with the
appropriate tool.
Dismantle the external labyrinth seal integral with
the grease valve (14) and extract with threaded tie-
rods; these components are mounted on the shaft
with a slight interference, therefore it is advised to
flame heat them to approx. 80°C for easier
extraction (some machines have the labyrinth seal
separated from the grease valve). Remove the
screws (4) and the bearing fixed external seals.
The figure shows the seals removal operation
using a puller.
Removal of seals with puller
Note: Some design solutions require that the
external seal and the grease valve are
incorporated in a single component.
Warning! In vertical axis motors the bearing free to
slide axially is mounted on coupling side D, whereas
the axially locked bearing, that sustains the weight of
the rotor is mounted on the opposite N coupling side
(top); it is therefore important to follow the dismantling
instructions exactly in the sequence indicated below.
Slightly lift the rotor from the coupling side with a
jack or a crane, attached to the end of the shaft
with a suitable cord, so as to relieve the weight of
the rotor from the bearing. Place a solid support
under the lifted end and release the rotor on the
support.
Remove the screws (15) that join the shield (16) to
the stator casing. Anchor the top part of the shield
to lifting equipment with a ring type eyebolt.
Extract the shield from the casing using two
appropriate screws inserted in the threaded holes
on the shield. When the shield (16) has come out
of its housing in the casing, rest it gently on the
shaft. The bearing (1) will still be mounted on the
shaft and also the internal flame arresters (5) will
still be in place.
Repeat these operations to free the other shield.
