Installation, operation and maintenance instructions
High voltage flameproof motors for explosive atmosphere
AMD Rg 355-400-450-500
First commissioning and supervision of operation
Issued by: MOLM
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Sheet No.
3AAM101035 E
Rev. B
Page 2 of 2
01.2023
Important remark:
Re-switching a running motor causes current and
torque fluctuations. Reclosure at an instant when the
system is in phase-opposition to the residual stator
voltage will subject the motor and the driven machine
to very high forces. This condition shall be avoided if
the whole shaft train is not dimensioned by design to
sustain these stresses.
Supervision and maintenance during the first start
The machine load, the regular cooling, the operation of
the bearings and the vibration level are essential factors
for the operation of the machine and need to be checked
regularly. During the first period of operation (24 hours),
supervision should be intensive, and the essential
factors must be recorded at least every hour.
It is suggested that these factors would be recorded on
maintenance card or computer files.
The temperature readings obtained by the sensors
placed in the stator winding and possibly in the bearings
need to be checked to ensure that they remain below the
maximum allowed limits. Compare the absorbed current
with the value given on the nameplate to check the
operating condition of the machine.
Motors with roller bearings (antifriction bearings)
In case of newly installed machine or a machine which
has been out of service for long time, inject new grease
immediately after the start up. When the motor is
running, make sure that the old grease and the excess
new grease are discharged through the openings in the
bottom of the bearings housing.
The temperature of the bearings will initially increase
because of the excess of grease. After few hours the
excess grease will be discharged, and the bearings’
temperature will return at normal values.
Horizontal motors with sleeve bearings
After the start-up check that there is no contact between
stationary and rotating parts and that no abnormal noise
is coming from the motor. Pay attention to the oil
tightness of the tubes connections. It is recommended a
bearing full inspection after a running on load for few
hours or after substitution of bearings’ components.
The rotation of the lubrication ring can be verified
through the inspection hole on the top of the bearing
housing. Check the temperature and the oil level
frequently during the first hours of rotation.
In case of oil feeding from outside equipment check the
incoming oil pressure and the rate of oil flow. Refer to
the specific technical documentation for the required
value.
Vibration.
Check the vibration level with a suitable portable
instrument. The vibration probe can be fixed to the
bearing housing or to the end-shields.
Compare the measured values to the values prescribed
in the applicable Standards. In case of doubt or problem
it is useful to analyze the frequency spectrum of the
vibration signal. For the prescribed value see the Sheets
"Maintenance of the bearings" of this manual.
SUPERVISION OF THE OPERATION
The operating personnel shall inspect the machine
frequently. The purpose of the inspection is also to
familiarize personnel with the equipment. This is
imperative to permit the detection and correction in time
of possible abnormal occurrences.
Check always before starting that no shut-down
precaution or means have been forgotten (i.e. the
standstill heating equipment) and that the lubrication and
cooling means are functioning.
The run inspections must cover the following points:
Bearings:
bearing temperature
noise from the bearings
oil level or oil flow
absence of oil leakages
vibration
Cooling:
temperature of the stator winding
normal flow of cooling air
cleanness of cooling air
surface temperatures
Remark: if the cooling air contains dust, clean
regularly the cooling surfaces of the motor.
Miscellaneous:
noise
vibration level
indications of alarm or fault
