Edwards SCU-801

SCU-801 Control Unit for Turbomolecular Pump
MT-95E-001-A
Page 120
8
MAINTENANCE
Referred
section
3.4.1 3.4.3
*1 The driver
output
stops and the rotor continue rotating by
inertia.
It may take several hours to stop
. To stop the STP pump quickly, close the vacuum valve at the outlet port flange
and introduce gas from the purge port into the STP pump.
Table
35 - Error
messages after self test
Countermeasures
Check the vacuum piping system for leakage. Check the exhaust sequence.
Contact
Service office.
1. Perform rotational
operation
after resetting.
2. Contact
Service office.
Contact
Service office.
Contact
Service office.
1. Set the ambient
temperatur
e to 40 ºC (104
ºF) or less.
2. Remove obstacle from the
ventilation port.
Probable causes
Atmospheric air flows the STP pump
.
Failure of the
SCU-801.
1. Malfunction by external
noise
.
2. Failure of the SCU
-801.
1. Disconnection of
connection cable or at connector part
2. STP pump failure
.
Short
-circuit or ground fault in
the connection cable or at connector part
.
1. High ambient temperature. 2. Insufficient cooling of the
SCU-801.
Pump operation
Decelerate and stop, then Touch down
.
The magnetic bearing output stops and the rotor is descended on the protection bearing.
Free run.
*1
Decelerate
and stop.
Touch down
. The
magnetic bearing output stops and the rotor is descended on the protection bearing.
Touch down
. The
magnetic bearing output
stops and the
rotor is descended on the protection bearing.
Continuance of rotation.
Occurrence condition
Rotational speed rises when deteriorating or stopping.
When the rated operation does not stop approx. 30 min. after start operation is executed.
Accelerate up to 500
rpm
or less
.
Disconnection of magnetic bearing control current.
Excessive magnetic bearing electric current
.
Overheat inside the SCU-801.
LCD Messages
Aberrant Accel
Aberrant Brake
Accel Malfunction
AMB Ctrl Lost
Amp
Overcurrent
CAUTION: CNT heat1