TECHNICAL INFORMATION
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 inten-
sity, 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 AND SPARE PARTS
DESCRIPTION PART
NUMBER
Mains cable NEMA Plug, 3m long
969-9958
Mains cable European Plug, 3m
long
969-9957
Serial cable and Navigator
Software
969-9883
Inlet screen, ISO 100
969-9302
Inlet screen, ISO 160
969-9303
Heater band, 120 V
969-9804
Heater band, 220 V
969-9803
Water cooling kit
969-9337
Plastic water cooling kit
969-9347
Air cooling kit for Navigator
Controller
969-9299
Fan extension cable
969-9949
Bracket for Navigator Controller
side mounting
969-9970
Vibration isolator, ISO 100
969-9344
Vibration isolator, CF 6"
969-9334
Vibration isolator, ISO 160
969-9345
Vibration isolator, CF 8"
969-9335
Vent flange, NW 10 KF / M8
969-9108
Vent device with adjustable delay
time for standard rack controller
969-9831
Vent valve for standard rack con-
troller
969-9843
Vent valve for Navigator Controller
969-9834
Purge valve with KF16 flange
969-9239
Purge valve with 7/16” flange
969-9240
Purge valve KF16-M12 20 SCCM
969-9241
Purge valve 7/16-M12 20 SCCM
969-9242
Foreline flange KF25 1/4 gas
969-9130
Forepump DS 302, with 1 ph.,
universal motor
949-9325
Forepump MD 60, 120 V
949-9411
Forepump MD 60, 220 V
949-9412
90
87-900-946-01(F)
