TECHNICAL INFORMATION
Connection C – ELECTRICAL
The turbopump is connected to the controller
through an 8-pin connector. Pins B, C and D are
the 3-phase supply to the motor, pins A and F are
connected to the temperature sensor (NTC type,
30 K
Ω
resistance at 25° C) and pin E is connected
to the pump ground; pins G and H are not con-
nected.
If the temperature sensor is disconnected, the
pump will not start. To prevent damage to the
pump when the temperature exceeds 60° C, the
sensor automatically cuts out the power supply.
PUMP USED WITH CORROSIVE GASES
To prevent damage to the bearings, an inert gas
must flow into the pump body around the upper
bearing towards the forevacuum line. To supply
the inert purge gas (e. g. nitrogen) to the pump
through the purge port, connect a gas purge valve
between the pressure regulator and the pump.
Adjust the pressure regulator in order to read a
gas flow rate of 0.1 to 0.8 mbar l/s.
!
CAUTION
To prevent bearing damage, Varian suggests a
minimum purge gas flow rate of 10 sccm (0.17
mbar l/s). This value can be exceeded, according
to the process requirements. Please contact Var-
ian for specific applications.
The purge gas throughput with the recommended
forepump of 15 m
3
/h (11 CFM) allows to achieve a
high vacuum pressure in the 10
-8
mbar range.
The recommended gas flow maintains a pressure
into the pump body higher than the forevacuum
pressure.
The recommended procedure to vent the system
and the pump avoiding the contact between the
pump bearings and the corrosive gas is described
in the following points:
1. Close the corrosive gas flow into the system.
2. Leaving the Turbo-V pump and the backing
pump running and the purge gas flowing, wait
for enough time to evacuate the corrosive gas
from the system.
3. Open the Turbo-V vent port slowly until to
reach atmospheric pressure in the system.
4. Turn off the Turbopump.
5. When the Turbo-V pump and the backing
pump are stopped and the system is at at-
mospheric pressure, for a better bearing pro-
tection it is advisable to leave the purge gas
flowing into the Turbo-V pump, with the cham-
ber or the Turbo-V vent valve opened, to avoid
system overpressures. If the vent valve can’t
be kept opened, the backing pump should be
left operating.
Purge layout
1. Purge gas line
2. Pressure
regulator
3. Gas purge valve
4. Gas purge port
5. Forevacuum
pump
6. Turbopump
7. Vent
valve
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87-900-973-01
