Operating The Pump; Low Speed Operation - Varian Turbo-V 150HT Bedienungshandbuch

After START command, frequency
maximum level, then the
value proportional to the pump rotational speed (about 3
KRPM if the pump is completely stopped).
The pump will accelerate to its normal rotational speed.
•
During acceleration of the pump or during any
operating condition, it is always possible to select the
other parameters to be displayed pressing the PUMP
CURRENT or the CYCLE NUMBER pushbuttons.
•
After the run up time and when the normal rotational
speed is reached, the display will be as follows, even
if any previous display selection was made, and the
normal condition has been reached.
N O R M A L
X X
where: XX = indicates the rotational speed (62 KRPM for
high speed, or 41 KRPM for low speed).

Operating the Pump

After the starting period, if the system has a vacuum leak
or the pressure in the pump chamber is high (from 1 mbar
to atmosphere), the pump continues to operate indefinitely.
If the gas load at the turbopump inlet flange continues to
stay high, the power drawn by the turbopump increases up
to the maximum value (230 W with water cooling, or 90 W
with air cooling).
Then the Turbo-V pump is slowed down in pro- portion to
the gas load at least until it reaches about 4 or
3 KRPM.
As soon as the gas load decreases, the pump will
automatically accelerate to reach normal operation. The
pump can be stopped at any rotational speed and can be
restarted at any rotational speed from either the front panel
buttons or the remote connections. The controller
automatically synchronizes the output to the rotational
speed of the pump and then accelerates linearly up to the
nominal speed or within steps if the Soft Start has been
selected.

Low Speed Operation

This feature is provided for operating the pump at
moderate high pressure with high gas throughput.
To operate in this low speed mode, engage the
LOW SPEED push-button once if the display shows:
output will be at the
frequency will decrease to a
O P E R A T I O N
K R P M
R E A D Y
S O F T S T A R T
or:
P U M P R E A D Y
S T A R T
or:
N O R M A L
X X
or twice if the display shows other parameters, either
before starting the pump or after it is operating.
If LOW SPEED is selected before starting the pump, the
display shows:
R E A D Y
S O F T S T A R T
The pump reaches the Normal high speed, then decrease
the speed to the low speed value and the display shows:
A P P R O A C H
X X
If the Soft Start has been deselected the display shows:
P U M P R E A D Y
S T A R T
where: LS = means low speed mode is selected.
After starting, a LS appears on the right bottom corner of
the following displays:
S O F T S T A R T
[ - - -
P U M P I
1 2 X X
N O R M A L
X X
72
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