Operating Steps; Welding In Tig Mode; Remote Control Operation - Lincoln Electric SQUARE WAVE IM687 Operator's Manual

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6. REMOTE CONTROL CONNECTOR - This connector
provides connection for a remote control. See Remote
Control Operation in this section of the manual.
7. ELECTRODE/GAS OUTPUT RECEPTACLE - This
quick connect receptacle provides electrical connec-
tion to the electrode holder and cable for Stick weld-
ing and a combined electrical and gas connection
for the TIG torch when TIG welding.
8. WORK CABLE - This work cable is factory con-
nected to the welder and is connected to the work
piece to complete the welding circuit. Refer to
Machine Grounding and High Frequency
Interference Protection in the Installation section
of this manual for the proper procedure on ground-
ing the work clamp and work piece to minimize high
frequency interference.

OPERATING STEPS

WELDING IN TIG MODE

1. Connect the TIG torch and cable quick connect plug
to the Electrode/Gas output receptacle. This recep-
tacle also contains an integral gas connection for the
torch. Connect the work clamp to the work piece.
2. Set the TIG/STICK switch to "TIG".
3. Set the Polarity Switch to DC- for welding steel or
stainless steel; or to AC for welding aluminum.
4. Connect the Foot Amptrol to the Remote Control Connector.
5. Turn on the cylinder gas valve and adjust the flow
regulator to obtain desired flow.
6. Turn the power switch to "ON". NOTE: There will be
a 15 second gas flow when the power is turned on.
7. Set the Current Control on the control panel to the
maximum desired amps.
8. Depress the Foot Amptrol to energize the torch and
establish an an arc with the work piece.
NOTE: When the TIG/STICK switch is set to "TIG",
depressing the remote control will start a 0.5 second gas
pre-flow before energizing the TIG torch. When the remote
control is released the TIG torch is de-energized and gas
flow will continue for a 15 second post flow. When the
polarity switch is set to DC, the TIG Arc Starter will turn on
and off automatically to start and stabilize the arc. In AC the
TIG Arc Starter will turn on with the output and remain on
continuously until the remote control is released.
OPERATION

REMOTE CONTROL OPERATION

A Foot Amptrol™ is included with the SQUARE WAVE
TIG 175 PRO for remote current control while TIG
welding. An optional Hand Amptrol may also be used.
An optional Arc Start Switch may be used to start and
stop the welding if no remote control of the current is
desired. Refer to the Accessories section of this man-
ual.
Both the Hand and Foot Amptrol work in a similar man-
ner. For simplicity, the following explanation will refer
only to "Amptrols", meaning both Foot and Hand mod-
els. The term "minimum" refers to a foot pedal in the
"up" position, as it would be with no foot pressure, or a
Hand Amptrol in the relaxed position, with no thumb
pressure. "Maximum" refers to a fully depressed Foot
Amptrol, or a fully extended Hand Amptrol.
When the welder is in TIG mode activating the Amptrol
energizes the electrode terminal and varies the output
welding current from its minimum value of 10 amps, to
the maximum value set by the Current Control on the
control panel. This helps eliminate accidental high cur-
rent damage to the work piece and/or tungsten, and
gives a fine control of the current. When the welder is
in the stick mode a remote control has no effect and is
not used.
It is important to note that, in some cases, the tungsten
will not start an arc at the minimum current because
the tungsten may be too large or cold. To start an arc
reliably, it is important to depress the Amptrol far
enough so that the machine output current is near the
tungsten operating range. For example, a 3/32" tung-
sten may be used on DC- to weld the full range. To
start the weld, the operator may have to turn the cur-
rent control up and depress the Amptrol approximately
1/4 of the way down. Depressing the Amptrol to its min-
imum position may not start the arc. Also if the current
control is set too low, the arc may not start. In most
cases, a large or cold tungsten will not readily establish
an arc at low currents. This is normal. In DC-, the
Square Wave 175 will start a 3/32, 2% thoriated tung-
sten electrode at 15 amperes provided the electrode
tip is properly grounded and not contaminated.
BENEFITS OF THE SQUARE WAVE DESIGN
In AC TIG welding of aluminum, the positive portion of
the AC wave provides cleaning (removal of aluminum
oxide) of the work piece. This is desirable on materials
with a heavy oxide coating such as aluminum.
However the positive portion may also cause the elec-
trode to overheat at high currents causing "tungsten
spitting". The negative portion of the AC wave offers
no cleaning action but concentrates more heat on the
SQUARE WAVE TIG 175 PRO
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