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Fore-Vacuum Pump Connection
A flange KF 40 NW is available to connect the Turbo-V 3K-G pump to
the fore-vacuum pump. A hose or vacuum approved pipe can be used.
If a rigid pipe is used, any vibration generated by the mechanical
pump must be eliminated through the use of bellows.
The Turbo-V 3K-G pump is characterized by its high compression ratio also for
NOTE
oil vapors. When using a mechanical oil-sealed pump, it is advisable to install a
suitable trap between the turbopump and the fore-vacuum pump in order to
prevent oil backstreaming.
Pump Used in Presence of Magnetic Fields
Magnetic fields induce eddy currents in the rotor of a turbomolecular
pump that tend to oppose to its rotation.
The result is increased electrical power consumption by the motor,
most of which is dissipated in the rotor.
Since the rotor is not in contact with the stator the above power can
leave the rotor mainly by radiation and hence the rotor may be
overheated while static parts of the pump remain cool.
This effect is strongly dependant from the intensity, time function
and distribution of the magnetic field.
In general, therefore, an increase in pump current can be expected.
If this increase is lower than 50 % of the current value drawn by the
motor in high vacuum operation, no particular problem should be
expected.
However if the effect is greater, than the case should be carefully
reviewed by Agilent's specialist. As a matter of fact, in case of high
magnetic fields, also important forces might be generated and applied
to the rotor.
Turbo-V 3K-G Pumping System User Manual / 87-901-011-01
Technical Information
Fore-Vacuum Pump Connection
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