8 Technical Reference 8.4 Interface Description
Signal processing in RUNNING:
• If the speed exceeds “Bowl speed, synchronous”
in Technical Data with more than 5% for a
period longer than 1 minute or momentarily
during maximum 5 seconds more than 10%
the separator shall be stopped automatically by
NORMAL STOP and a high speed alarm shall
be given.
• If the speed falls more than 10% below the
synchronous speed for a period longer than 1
minute or 15% during more than 5 seconds a
low speed alarm should be given. Low speed
indicates some malfunction of the separator
equipment and shall be investigated.
• The speed monitoring system shall be checked
continuously (e.g. by checking that pulses are
coming). In case of a failure indication an alarm
for speed monitoring system failure shall be
given. If there is a risk of too high speed the
separator shall be stopped by NORMAL S TOP.
• The speed drop during DISCHARGE. compared
to the measured speed immediately before,
should be between 3-8% which will indicate a
proper discharge.
Signal processing in STOPPING:
• STAND STILL shall be indicated when no pulses
are detected within 30 seconds.
• Stopping the separator when alarm for speed
monitoring system failure is active, shall cause
a timer controlled stop. (See “Stop time” in 8.2
Technical data on page 179.)
752 Unbalance sensor (optional).
For indication of any abnorma
l unbalance
and to be able to perform appr
opriate
countermeasures, the sepa
rator has been
equipped with an inductive
analogue sensor
monitoring the radial pos
ition of the Top bearing
seat on the separator fra
me. The signal from
the sensor shall be mo
nitored and two alarm
levels according to t
he vibration alarm levels in
Technical data on pa
ge 179 should be set.
The vibration level shall be high for 3 seconds to
generate an alarm. The first level is only used to
generate an alarm while the second level shall
stop the machine.
187
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