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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, ISO 200
Heating jacket
Water cooling kit for American
fractional tubes
Water cooling kit for Metric tubes
Pump to controller cable
Vent flange NW 10 KF (M8)
Vent valve with fixed delay time
Vent device with adjustable delay
time
Solid state flowmeter 1/4"
swagelock
Solid state flowmeter KF16
Forepump VSP60
Forepump VSR90
Forepump DS602 with 1 phase
worldwide motor
Forepump DS602 with 3 phase
worldwide motor
For a complete overview of Varian's extensive
product lines, please refer to the Varian catalog.
36
TECHNICAL INFORMATION
PART NUMBER
969-9316
969-9819
969-9338
969-9348
969-9953
969-9108
969-9833
969-9831
969-9114
969-9115
VSP60302
VSR90301
949-9335
949-9336
87-900-942-01(A)
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