![background image](http://html.mh-extra.com/html/abb/amd-rg-355/amd-rg-355_installation-operation-and-maintenance-instructions_3045307071.webp)
Installation, operation and maintenance instructions
High voltage flameproof motors for explosive atmosphere
AMD Rg 355-400-450-500
Rolling bearings maintenance and checking
Issued by: MOLM
Sheet No.
3AAM101040 E
Rev. B
01.2023
Page 3 of 11
We
res
er
ve
a
ll
rig
hts
in
this
doc
u
ment
an
d
in
th
e
in
format
io
n
cont
aine
d
ther
e
in.
R
epr
o
duc
tion,
us
e
of
di
sc
los
ur
e
to
thir
d
pa
rties w
itho
ut
expr
ess
auth
or
ity
is
s
trictly f
orbidd
en
.
The values are valid for:
Vibrations originating from the machine itself.
Machines on rigid foundations. Rigid foundations
definition in conformity with ISO standard 10816:
“For a rigid foundation the system natural
frequency is higher than the rotation speed
frequency”.
The values are
not
applicable (usually) for:
Alternative compressor drives.
Machines on foundations with low system natural
vibration frequency (ma foundations), i.e.
0.25 x rotation speed frequency
For these machines, it is opportune that the values are
agreed between the manufacturer and the customer at
the time of ordering.
Vibrations detected on the bearing housings
The decisive quantity is the actual vibration velocity
measured on the bearing housing. The position of the
measuring point is defined on the basis of ISO
Standard 10816.
The recommended values to set the protection devices
activation controlled by the detectors (or according to
decisions made based on manual measurement) are
the following:
ALARM
V
rms
= 4.5 mm/s
BLOCK
V
rms
= 7.1 mm/s
NOTE
: The above values are, in fact, lower than the
limits recommended by ISO Standard 10816. The
restriction of the allowed levels is due to the
particular design solutions of the Ex db motors flame
arresters, that have a very small gap between the
motor fixed part and the rotating shaft.
Converting of vibration velocity V
ms
to vibration
amplitude S
In order to have a comparison with the measured
values, the vibration amplitude S can be calculated as
follows (supposing that vibration is sinusoidal):
f= rotation frequency in revs per second
V
rms
= vibration speed (mm/sec)
S= vibration amplitude from 0 to peak (mm)
A conversion monograph is given below.
f
V
x
f
V
x
x
xV
S
rms
rms
rms
225
,
0
~
2
2
2