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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 consump-
tion 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 radia-
tion 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 opera-
tion, no particular problem should be expected.
However if the effect is grater, than the case
should be carefully reviewed by Varian's specialist.
As a matter of fact, in case of high magnetic fields,
also important forces might be generated and ap-
plied to the rotor.
ACCESSORIES
DESCRIPTION
Inlet screen DN100
Base fixing kit
Water cooling kit
Plastic water cooling kit
Air cooling kit (small)
Air cooling kit (large)
Vibration damper ISO 100
Vibration damper 6î CFF
Centering ring ISO 100
(with O-ring)
ISO clamp
Copper gaskets for 6î CFF
(10-Pack)
Nut and bolt set for 6î CFF
(25-Pack)
Vent valve with fixed delay time
Vent valve with adjustable delay
time
Vent flange NW 10 KF
Forepump DS 102, with 1 ph.,
universal motor
Forepump MDP 30, 120 V
Forepump MDP 30, 220 V
For a complete overview of Varian's extensive
product lines, please refer to the Varian catalog.
36
TECHNICAL INFORMATION
PART NUMBER
969-9302
969-9326
969-9337
969-9347
969-9310
969-9313
969-9344
969-9334
IC-100 SV
IC-063-100-A
FG-0600-CI
FB-0450-C12
969-9833
969-9831
969-9109
949-9315
949-9451
949-9452
87-900-881-01(B)
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