9 | OPERATION | 9 |
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(STEP 3) Second Press: The output ramps down to the level set with the Start/Crater Current control. The time it takes to ramp down is set with the Down slope Time control. (Approx. 0.5 to 10 seconds)
(STEP 4) Second Release: Output is turned off stop- ping the weld and a 15 second Postflow of shielding gas is applied.
1.If connecting a Lincoln
2. Set the MODE switch to
3.Set the Polarity Switch to DC- for welding steel or stainless steel; or to AC for welding aluminum.
4.Connect an Arc Start switch or Amptrol to the Remote Control Connector.
5.Turn on the cylinder gas valve and adjust the flow regulator to obtain the desired flow.
6.Turn the power switch to “ON - I”. 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.Set the Start/Crater Current control A
on the control panel to obtain the desired level as a percentage of the maximum current. Note: The level set must be above the machines minimum starting level. (12 Amps)
9.Set the Down slope Time control 
on the control panel to the desired level.
10.Depress the Arc Start switch or Amptrol to energize the torch and establish an arc at the Start current level with the work piece.
11.Release the Arc Start switch or Amptrol to ramp up to the maximum current setting.
12.Depress the Arc Start switch or Amptrol again to start the Down slope time.
13.Release the Arc Start switch or Amptrol to stop welding.
NOTE: 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 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 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 2 Step 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 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 4 Step TIG mode the Amptrol acts as an Arc Start Switch. 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 or Start/Crater current 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
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