Table of Contents
Advertisement
Installation, operation and maintenance instructions
High voltage flameproof motors for explosive atmosphere
AMD Rg 355-400-450-500
Preparation for commissioning – Mechanical steps
BEARINGS
ANTIFRICTION BEARINGS (Rolling-contact
bearings)
The bearings are filled with lithium soap grease
before delivery.
Periods of standstill lasting some months, as for
storage for instance, can result in oil separation from
the bearing lubricating grease. Dismantle the outer
bearing cover and, if this is the case, remove the
grease and oil residue. Replace the removed
grease with fresh grease of proper type and close
again the bearing cover.
Bearing temperature monitoring. If provided the
temperature detectors shall be set at the lower
possible temperature based on the test results and
operating
recommended for normal operating temperature
with standard lubricants and ambient temp. at 40°C
are:
Alarm: 90°C (194°F)
Trip:
100°C (212°F)
If high temperature grease is used (i.e. for machines
rated at class F working temperature) the a.m. limits
can be set 10°C (28°F) higher. Refer to the specific
technical documentation.
SLEEVE BEARINGS
Sleeve bearing machines are delivered without oil.
On machines with self-cooled bearing, i.e. not
having a separate oil supply system, the oil is
carried to the bearing faces by oil rings.
During longer shut-down periods the oil film
between the bearing shell and the bearing journal
will be pressed out by the weight of the rotor, i.e. the
bearing will be dry! Therefore, prior to rotate the
shaft (even by hand), at least 100 to 200 cm³ of oil
must be introduced manually into each bearing. This
can be done by removing the screw-plug or vent-
filter located on top of the bearing cover and
inserting a funnel into the exposed opening.
Be sure to use the correct type of oil.
When introducing the lube oil, only fill to the correct
level i.e. up to the middle of the oil sight window. A
higher oil level is not recommended as this could
cause oil leakage at the seals during operation.
Machines cooled by an axial external fan (HXR or
AMDR types) are provided on N.D.E. side with a
vent tube (with filter) coming out from the ventilation
hub to avoid the pressurisation of the bearing
enclosure.
Separately cooled plain bearings. The bearings
are connected to an oil supply system, which should
be in operation before the machine is started up and
condition.
The
maximum
remain in operation until the machine is turned
down. The maximum oil inlet temperature of the
bearings should not exceed 65°C.
Bearing temperature monitoring. If provided the
temperature detectors shall be set using the same
criteria applicable for antifriction bearings. The
maximum
values
operating temperature with standard lubricants and
ambient temp. at 40°C are:
Alarm: 90°C (194°F)
Trip:
100°C (212°F)
Laying the oil lines. Flexible pipe elements must
be fitted between the connection pipe or flange on
the motor and the oil supply lines to attain a tension-
free connection. This ensures for better, oil-tight
values
connection and also helps to avoid electrical
insulating parts from being damaged, if such are
fitted.
Before fitting, the lines should be tapped gently to
clear out scale, rust and sand, then washed out with
inhibited hydrochloric acid and rinsed with rinsing
oil. The inhibitor should be used to supplier's
instructions.
The oil return line must have a continuous slope of
5% (= 50 mm per 1000 mm of length) from the
connection flange on the motor bearing to the oil
tank. This is the minimum permissible slope!
Remember that the oil level of the bearings will
increase if the oil moves too slowly in the discharge
tubes. This can result in oil leaks or disturbance in
the flows.
On principle, oil return lines should be kept as short
as possible. Their free cross-section should be at
least as large as that of the outlet. Bends should be
avoided where possible. To avoid risk of oil
damming up or pressure build-up in the bearings,
these lines should contain no double bends or
siphons. Specifications on drawings have to be
taken into account, where applicable.
Inlet points have to be arranged in the direction of
flow. Pipe sections must be large enough to obtain
the following oil flow velocities:
- Oil inlet (full pipe section) less than 1.5 m/sec.
- Oil return (full pipe section) less than 0.17 m/sec.
In order to suppress the formation of oil foaming,
vertical drops > 1 m are to be avoided.
When the bearing seals incorporate a sealing-air
arrangement, it is important to ensure that there is
adequate venting of the housing. This can be done
via the oil return line or via a venting filter sufficiently
sized to prevent the escape of oil vapour.
Sheet No.
3AAM101034 E
Rev. B
01.2023
Page 1 of 2
recommended
for
normal
Issued by: MOLM
Advertisement
Table of Contents
