TECHNICAL INFORMATION
8
87-900-847-01 (B)
Starting the Pump
If the forepump and vent device are not operated by the
controller, close the vent valve and switch on the
forepump.
NOTE
With the FRONT panel operation selected, the
REMOTE and RS232 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.
•
Press the START push-button or use the remote or
RS 232 start signal, the display shows:
P U M P
I
S
S T A R T
I
N G
1
2
X X
K R P M
where:
1 2
= contrast inverted identifies the set point
condition:
−
1
is displayed when relay R1 is de-energized.
−
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 frequency (range 3 to 99 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 (1/4 of nominal frequency 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
O P E R A T
I
O N
X X
K R P M
where:
XX
= indicates the rotational 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 CYCLE NUMBER push-buttons).
If this is the case when the pump reaches the
normal speed, the display reverts to the previous
figure.
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 3 KRPM.
Even if any previous display selection was made.
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 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
NOTE
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, either before starting the pump or
after it is operating.
If LOW SPEED is selected before starting the pump,
the display shows as follows:
P U M P
R E A D Y
:
P U S H
S T A R T
B U T
T O N
L S
where:
LS
= means low speed mode is selected.