Lincoln Electric IM761 POWER FEED 15M - Manual (Page 28)

B-14 OPERATION B-14
2 STEP - 4 STEP - TRIGGER OPERATION
The 2 Step - 4 Step switch changes the
function of the gun trigger. 2 Step trigger
operation switches the welding output
ON-OFF in direct response to the trigger.
4 Step trigger operation provides
“ trigger
interlock ” capability and gives the ability
to control the amount of time spent in the
arc start and arc crater steps.
Place the toggle switch in the DOWN
position for 2 Step operation and in the
UP position for 4 Step operation.
The 2 Step - 4 Step trigger has no effect when weld-
ing with SMAW or CAG procedures.
• 2 STEP TRIGGER
2 Step trigger operation is the most common. When
the gun trigger is pulled, the welding system (power
source and wire feeder) cycles through the arc start-
ing sequence and into the main welding parameters.
The welding system will continue to weld as long as
the gun trigger is activated. Once the trigger is
released, the welding system cycles through the arc
ending steps.
• 4 STEP TRIGGER
4 Step trigger operation gives the welder additional
control in the welding sequence. 4 step trigger
allows the welder to choose the arc start, weld and
arc end time. It may also be set-up to work as a trig-
ger interlock.
EXAMPLE 1 - 2 STEP TRIGGER: Simple operation
The simplest trigger operation occurs with a 2 Step
trigger and the Start, Crater and Burnback functions
all set to OFF. (See Figure B.6)
For this sequence,
PREFLOW:
Shielding gas begins to flow immediately when the
gun trigger is pulled.
STRIKE:
After preflow time expires, the power source regulates
to the welding output and wire is advanced towards
the work piece at the Strike
WFS . If an arc is not
established within 1.5 seconds, the wire feed speed
will jump to the welding wire feed speed.
WELD:
The power source output and the wire feed speed
continue at the weld settings for as long as the trigger
is pulled.
POSTFLOW:
As soon as the trigger is released, the power source
output and the wire feed speed are turned OFF.
Shielding gas continues until the post flow timer
expires.
POWER FEED 15M
2-
-STEP 4
STEP
Shielding
Gas
Idle Preflow Strike Weld Pos tflow Idle
Power
Source
Output
WFS
O n
O ff
Run- in
O ff
Wel d
O ff
Wel d
Arc
Established
T
rigger
Pulled
T
rigger
Released
2 Step Tri gger
Start = OFF
Crater = OFF
Burnback = OFF
1.5 sec max.
FIGURE B.6