GA05141_0702 - 09/2004
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Operation
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 equipped 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 (e.g. from other pumps) when the pump is
running. Shocks perpendicular to the rotation axis are particularly harm-
ful. If the pump appears to be running in the mechanical bearings con-
tinuously it is switched off.
■ Do not suddenly expose the MAG to an already evacuated 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.
■ Do not stop the MAG with the mains. Use the STOP key or a stop com-
mand. 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.
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 2.6.
The pump can become so hot during operation that it represents
a burn hazard:
Frequent acceleration and deceleration of the pump or operating cycles
between stand-by and normal operation put pressure on the rotor.
Therefore it has to be changed after 5000 start or stand-by cycles.
Warning
Warning
Protecting the
touch-down bearings
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