Lincoln Electric IM702-A manual Figure B.5

B-11 OPERATION B-11

The new foot pedal provides such independent action distinction of precisely where the arc start switch actu- ates without over-riding minimum control pedal posi- tion, and precisely where the control pedal has been returned to minimum position without inadvertently de- actuating the arc start switch. The result is repeatable consistency in TIG weld starting and crater-fill for man- ual process control.

Using this new foot pedal with the Precision TIG’s new presettable Minimum Output level, in addition to the presettable Maximum Output level, further enhances the starting and crater level consistency as well as the control resolution of the manually controlled foot pedal.

FIGURE B.5

Foot

Rock Toe

Control Pressure

Switch

	Adjustable
	or
	Removable
	Heel Stop
Fully Pressed		Maximum Output
Control Pedal		Machine Setting

At-Rest					Minimum Output
Control Pedal					Machine Setting
	Off			Tim		e
		Pressed	At-Rest
	Switch Pedal		Switch Pedal

Setup for TIG Amptrol Welding

FIGURE B.6

AC Balance

AUTO

or

Set:

Standard Controls

Power Switch

ON

Mode Switch

TIG

Polarity Switch

AC or DC-

More + for alum.oxide "Cleaning" w/o"Spitting" or "wetting"loss.

Balanced for equal + and - current. More - for higher "Penetration".

Min. to Max. Amptrol

Max. to Min.

Amptrol

Pulse Frequency

4-6 pps is a typical initial setting.

Set for bead shape and travel speed: Higher for thinner plate and faster travel. Lower for thicker plate and slower travel.

% On Time

40-60%is a typical initial setting.

Set for total heat of Peak current:

Lower reduces distortion and burn-thru.

Background Current

40-60%is a typical initial setting.

Set as low as will maintain a pulse arc (Will not drop below Min.Output setting.)

Local/Remote

Switch

REMOTE

Maximum Output

Set to desired max. Amptrol output level.

Minimum Output

Press Display switch

and Set to desired min. Amptrol (Start/Crater) output level.

Postflow

Set as low as required.

Higher for larger

tungsten and current.

Advanced Panel

Controls

Trigger Switch

2-STEP

Pulse Switch

ON or OFF

Downslope

ZERO

For no arc-out delay.

PRECISION TIG 275