Remote Voltage Control Kit (Optional; Burnback And Postflow Timer Kit (Optional; Cold Feed/Gas Purge Switch - Lincoln Electric LF-74 Operator's Manual

B-4
1. WIRE FEED SPEED KNOB
The large, calibrated wire feed speed knob makes for
easy and accurate adjustment of the wire feed speed.
The knob rotates 3/4 turn. Turn the knob clockwise to
increase the wire feed speed, and counter clockwise
to reduce the wire feed speed.
K2426-1 and K2426-2 models:
These wire feeders are factory configured for normal
speed operation. The normal wire feed speed range is
100 to 800 in/min (2.5 - 20.3 m/min).
K2426-4 and K2426-5 models:
These wire feeders are factory configured for normal
speed operation. The normal wire feed speed range is
50 to 800 in/min (1.27 - 20.3 m/min).
K2426-3 model:
The wire feed speed range on the extra torque model
is 50 to 400 in/min (1.3 – 10.2 m/min).
2. REMOTE VOLTAGE CONTROL KIT
The optional remote voltage control kit adjusts the
arc voltage from the minimum to the maximum volt-
age of the welding power source. Rotate the knob
counterclockwise to reduce the arc voltage and rotate
the knob clockwise to raise the arc voltage.
3. BURNBACK AND POSTFLOW TIMER KIT
The optional Burnback and Postflow Timer Kit gives
control over the shielding gas at the end of the weld
and prepares the end of the wire for the next arc
start. Additional shielding gas protection is often
required when welding aluminum, stainless steel or
exotic alloys.
When stitch welding, set the postflow time to maxi-
mum for best results.
Burnback Timer
The burnback timer range is OFF to 0.25 seconds.
The burnback timer controls the additional amount of
time the power source output remains ON after the
wire drive has stopped feeding wire. Burnback
adjustment prevents the wire from sticking to the weld
at the end of a weld and helps to condition the wire
for the next weld.
OPERATION
To set the burnback time, adjust the knob to approxi-
mately 0.03 seconds and then decrease or increase
the time as desired.
Postflow Timer
The postflow timer range is OFF to 10 seconds.
Postflow is the time from when the power source out-
put turns OFF until the postflow timer expires. Use
postflow to protect the weld while the weld cools.
4. THERMAL LED, MOTOR OVERLOAD
The thermal light illuminates when the wire drive
motor draws too much current. If the thermal light illu-
minates, the wire drive will automatically shutdown for
up to 30 seconds to allow the motor to cool. To start
welding again, release the gun trigger, inspect the
gun cable, liner (and conduit). Clean and make
repairs as necessary. Start welding again when the
problem has been safely resolved.
For best results, keep the gun cable and conduit as
straight as possible. Perform regular maintenance
and cleaning on the gun liner, conduit and gun.
Always use quality electrode, such as L-50 or L-56
from Lincoln Electric.

5. COLD FEED/GAS PURGE SWITCH

Cold Feed and Gas Purge are combined into a single
spring centered toggle switch.
To activate Cold Feeding, hold the switch
in the UP position. The wire drive will
feed electrode but neither the power
source nor the gas solenoid will be ener-
gized. Adjust the speed of cold feeding
by rotating the WFS knob. Cold feeding,
or "cold inching" the electrode is useful
for threading the electrode through the
gun.
Hold the toggle switch in the DOWN position to acti-
vate Gas Purge and let the shielding gas flow. The
gas solenoid valve will energize but neither the power
source output nor the drive motor will be turned on.
The Gas Purge switch is useful for setting the proper
flow rate of shielding gas. Flow meters should
always be adjusted while the shielding gas is flowing.
LF-74
B-4