Operating Steps, Welding in TIG Mode | Lincoln Electric TIG 175 PRO

8	OPERATION	8

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.

REMOTE CONTROL OPERATION

A Foot Amptrol™ is included with the SQUARE WAVE TIG 175 PROPROfor 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 manu- al.

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 electrode 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 work. The AC waveform of the SQUARE WAVE TIG 175