Operating The Pump; Low Speed Operation - Varian Turbo-V 70 Bedienungshandbuch

•
If the Soft Start mode has been deselected the display
will change and shows:
P U M P I S
1 2 X X
where:
1 2 = contrast inverted identifies the set point
condition:
− 1 is displayed when relay R1 is de-energized
and the related output is zero voltage.
− 2 is displayed when relay R2 is energized.
XX KRPM = indicates the actual theoretical
rotational speed of the pump as a function of the
controller output
75 KRPM).
•
After START command, frequency output will be at
the maximum level, then the frequency will
decrease to a value proportional to the pump
rotational speed (about 9 KRPM if the pump is
completely stopped).
The pump will accelerate to its normal rotational
speed and when this 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
(75 KRPM for high speed, or 50 KRPM for low
speed).
During acceleration of the pump or during any
operating condition, it is always possible to select
the other parameters to be displayed (PUMP
CURRENT or
push-buttons).
If this is the case when the pump reaches the
normal speed, the display reverts to the previous
figure.
S T A R T I N G
K R P M
frequency (range 9
O P E R A T I O N
K R P M
the rotational speed
CYCLE NUMBER

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. Than the Turbo-V
pump is slowed down in proportion to the gas load at
least until it reaches about 9 KRPM.
This will occur either in NORMAL operation or with the
LOW SPEED selected.
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
to
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

With the FRONT panel operation selected, the remote
and RS 232 operations are inoperative; conversely, the
CYCLE NUMBER and PUMP CURRENT pushbuttons
are always active, even when the operating mode
selected is REMOTE or RS 232.
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:
P U M P
I N T E R L O C K
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
63
TECHNICAL INFORMATION
NOTE
W A I T I N G
F O R L O C A L
S T A R T
87-900-869-01 (B)
L S