Lincoln Electric INVERTEC V270-T AC/DC Manuel D'utilisation page 10

1. Press and hold the TIG torch trigger to start the
sequence. The machine will open the gas valve to
start the flow of the shielding gas. After the preflow
time, to purge air from the torch hose, the output of
the machine is turned ON. At this time the arc is
started according to the selected welding mode.
After the arc is started the output current will be
increased at a controlled rate, or upslope time, until
the Welding current is reached.
2. Release the TIG torch trigger to stop welding. The
machine will now decrease the output current at a
controlled rate, or downslope time, until the Crater
current is reached and the output of the machine is
turned OFF.
After the arc is turned OFF, the gas valve will
remain open to continue the flow of the shielding
gas to the hot electrode and work piece.
As shown above, it is possible to press and hold the TIG
torch trigger a second time during downslope to end the
downslope function and maintain the output current at
the Crater current. When the TIG torch trigger is
released the output will turn OFF and the postflow time
will start. This operation, 2-step restart disabled, is the
default setting from the factory.
4-Step Sequence
With the 4-step trigger mode and a TIG welding mode
selected, the following welding sequence will occur.
1. Press and hold the TIG torch trigger to start the
sequence. The machine will open the gas valve to
start the flow of the shielding gas. After the preflow
time, to purge air from the torch hose, the output of
the machine is turned ON. At this time the arc is
started according to the selected welding mode.
After the arc is started the output current will be at
the Start current. This condition can be maintained
as long or as short as necessary.
If the Start current is not necessary, do not hold the
TIG torch trigger as described at the beginning of
this step. In this condition, the machine will pass
from Step 1 to Step 2 when the arc is started.
2. Releasing the TIG torch trigger starts the upslope
function. The output current will be increased at a
controlled rate, or upslope time, until the Welding
current is reached.
3. Press and hold the TIG torch trigger when the main
part of the weld is complete. The machine will now
decrease the output current at a controlled rate, or
downslope time, until the Crater current is reached.
This Crater current can be maintained as long or as
short as necessary.
This sequence has an automatic restart so welding
will continue after this step. This operation, 4-step
restart enabled, is the default setting from the
factory. If the weld is completely finished, use the
following sequence instead of step 3 described
above.
3A. Quickly press and release the TIG torch
trigger. The machine will now decrease the
output current at a controlled rate, or downslope
time, until the Crater current is reached and the
output of the machine is turned OFF. After the
arc is turned OFF the postflow time will start.
4. Release the TIG torch trigger. The output current
will again increase to the Welding current, like in
step 2, to continue welding. When the main part of
the weld is complete go to step 3.
As shown here, after
the TIG torch trigger is
quickly pressed and
released from step 3A,
it is possible to press
and hold the TIG torch
trigger another time to
end the downslope
time and maintain the
output current at the
Crater current. When
the TIG torch trigger is
released the output will
again increase to the
Welding current, like in step 4, to continue welding.
When the main part of the weld is complete go to step 3.
A-5