Operating Steps; Welding In Tig Mode; Remote Control Operation; Benefits Of The Square Wave Design - Lincoln Electric SQUARE WAVE TIG 175 Service 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 con-
nection to the electrode holder and cable for Stick
welding and a combined electrical and gas connec-
tion 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
receptacle 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
OPERATION
and remain on continuously until the remote control is
released.

REMOTE CONTROL OPERATION

A Foot Amptrol™ is included with the Square Wave
TIG 175 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
manual.
Both the Hand and Foot Amptrol work in a similar
manner. For simplicity, the following explanation will
refer only to "Amptrols", meaning both Foot and Hand
models. 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
12 amps, to the maximum value set by the Current
Control on the control panel. This helps eliminate acci-
dental high current 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 tung-
sten 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" tungsten may be used on DC- to weld the full
range. To start the weld, the operator may have to
turn the current control up and depress the Amptrol
approximately 1/4 of the way down. Depressing the
Amptrol to its minimum 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 tungsten electrode at 15 amperes pro-
vided 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
SQUARE WAVE TIG 175
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