8.4 INTERFACE DESCRIPTION 8 TECHNICAL REFERENCE
156
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 STOP.
• 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
Technical Data.)
752 Unbalance sensor (optional).
For indication of any abnormal unbalance and
to be able to perform appropriate
countermeasures, the separator has been
equipped with a vibration velocity transducer
on the separator frame. The signal from the
transducer shall be monitored and two alarm
levels according to the vibration alarm levels in
Technical Data should be set.
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