3 Operation
3.1 General operation rules
The magnetic bearing in the MAG are immune to wear.
In addition to the magnetic bearings, the MAG is equip-
ped with touch-down bearings which protect the rotor
against mechanical contact with the stator if the pump is
subjected to external shock loading or when the pump is
switched off. These touch-down bearings have a limited
service life. Please observe the following in order to
obtain maximum service life.
• Avoid shock and vibrations when the pump is run-
ning. Shocks perpendicular to the rotation axis are
particularly harmful. If the pump appears to be run-
ning in the mechanical bearings continuously it is
switched off.
• Do not suddenly expose the MAG to an already eva-
cuated vacuum chamber. The pressure surge may
cause the rotor to make contact with the touch-down
bearings. This will cause increased wear.
• Do not disconnect the MAG and MAG.DRIVE while
they are operating. If MAG and MAG.DRIVE have
been disconnected accidently re-connect them.
• When venting the MAG the values shown in the pres-
sure rise curve must be maintained; see Fig. 30.
• Do not stop the MAG with the mains. Use the STOP
key or a stop command. Switching off the mains while
the pump is running will wear out the touch down
bearings.
The pump may make noise during the run-up and run-
down phases. This has neither an influence on the pump
nor on the process.
Warning
Monitor the purge gas continuously.
Insufficient purge gas flow can result in:
- Process gases entering the motor and
bearing area of the MAG
- Process gases escaping from the purge
gas valve
- Humidity entering the pump.
Refer to Section 2.7.
Warning
The pump will be hot during operation. Burn
hazard!
Operation
32
GA 05.139/1.02 - 06/99
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