Lincoln Electric SQUARE WAVE TIG 275 IM609-B Operator's Manual page 26

B-9
8. Set the Post Flow Time with the post flow knob.
Post flow control knob adjusts the time that the
shielding gas flows (and cooling water flow, if the
optional water solenoid is used) after the weld
cycle. Use short post flow times with low currents
and small tungstens, use long post flow times at
high output currents with large tungstens.
9. With the torch held safely away from everything,
press the Arc Start Switch or Amptrol and set the
gas flow meter. Release the switch or Amptrol. The
welder is now ready for welding.
10. Position the tungsten electrode at the start of the
weld at a 65˚ to 75˚ angle with the horizontal so
that the electrode is approximately 1/8" (4 mm)
above the work piece. Press the Arc Start Switch.
This opens the gas (and optional water solenoid)
valves to automatically purge air from the hose
and torch. After a 0.5 second preflow time, the
high frequency becomes available to strike the arc.
11. Hold the Arc Start Switch or Amptrol down until an
arc is established. If using an Amptrol, read the
Section on Hand and Foot Amptrol Operation.
Release the Arc Start Switch or Amptrol to stop
the arc and start the Post Flow timer. After the
Post Flow time has expired, the gas and (optional
water solenoid) valves will close. To make anoth-
er weld, repeat steps 10 and 11.
WELDING IN TIG MODE (4-STEP)
RELEASE #1
(STEP #2)
PRESS #1
(STEP #1)
START
CURRENT
DOWNSLOPE
(0.5 to 10 sec. ADJUSTABLE
PREFLOW
(0.5 sec. FIXED)
OPTIONAL
TIG PULSER
In 4-STEP mode an Arc Start switch must be used.
The switch is pressed and then released to start the
weld cycle. Pressing and releasing the switch a sec-
ond time ends the weld cycle. This eliminates the need
to continuously hold down the switch during the weld.
The process works as follows:
(STEP #1) First Press: Initiates a 0.5 second preflow
of shielding gas then starts the weld at a current equal
to 5 Amps or 25% +/- 10 % of preset current (whichev-
er is greater).
OPERATION
PRESS #2
(STEP #3)
PRESET CURRENT
RELEASE #2
(STEP #4)
CRATER CURRENT
POSTFLOW
(5 to 50 sec. ADJUSTABLE)
SQUARE WAVE TIG 275
(STEP #2) First Release: The output current ramps up
to the preset level in 0.5 seconds.
(STEP #3) Second Press: The output current ramps
down to 5 Amps or 25% +/- 10 % of the preset current
(whichever is greater). The time it takes to ramp down
can be adjusted from approximately 0.5 to 10 seconds
with the Down Slope Time control knob.
(STEP #4) Second Release: Output is turned off stop-
ping the weld and starting the 5 to 50 seconds post
flow set with the Post Flow control knob.
1. Connect the Twist Mate plug to the receptacle locat-
ed on the front of the machine. The connection
locks into place with a quarter turn making both the
power and gas connections. See the TIG TORCH
CONNECTION section to install the Twist Mate plug
on your torch.
2. Connect an Arc Start Switch to the Remote
Amphenol.
3. Turn the welder, gas supply and water supply (if so
equipped), on. The digital ammeter/voltmeter dis-
play will illuminate when the power is on. NOTE:
Cooling fan may not be "ON" when not welding.
(See MAINTENANCE section)
4. Set the MODE switch to "4-STEP TIG".
5. Set the peak current displayed on the digital amme-
ter with the output control knob.
6. Select AC or DC- electrode polarity. See Table B.2.
7. If welding with AC polarity, set the AC Wave
Balance Knob to Auto Balance™. This gives the
optimum ratio between cleaning and penetration,
automatically adjusted for the output current. If
manual adjustment of the AC Wave Balance is
desired, adjust the wave balance to the desired set-
tings. See the Advanced Features section for more
information on setting and using the AC Wave
Balance.
8. Set the Post Flow time with the Post Flow knob.
Post Flow time provides shielding gas flow (and
cooling water, if used) after the weld. Use short
Post Flow times with low currents and small tung-
stens and long Post flow times at high output cur-
rents and large tungstens.
9. Set the Downslope Time with the Downslope Time
Knob. This will adjust the time of the crater fill peri-
od.
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