Lincoln Electric IM812-A - Manual (Page 17)

B-6 OPERATION B-6
a. Cut the electrode within approximately
3/8”(9.5mm) of the end of the contact tip for solid
wire and within approximately 3/4”(19.1mm) of the
extension guide for cored wire.
b. Position electrode over joint. End of electrode
should be slightly off the work.
c. Lower welding helmet, close gun trigger, and
begin welding. Hold the gun so the contact tip to
work distance gives the correct electrical stickout
as required for the procedure being used.
NOTE: If the arc voltage is not within the proper
procedure range adjust the power source output
control. (The CC mode WIRE SPEED setting should
not be changed from the preset procedure value for
the proper arc voltage.)
d. To stop welding, release the gun trigger and
then pull the gun away from the work.
PROCEDURE AT END OF COIL
When the wire on the reel is used up, the following
procedure is to be followed for removing the old wire
from the gun cable and loading a new reel.
a. Shut off power source if a Remote Output Control
Option or internal contactor is not used.
b. Cut the end of the electrode off at the gun end.
Do not break it off by hand since this puts a slight
bend in the wire and makes it difficult or
impossible to pull it back through the nozzle.
c. U n c o u p l e t h e g u n c o n d u c t o r c a b l e f r o m
the LN-35.
d. Lay the cable out straight.
e. Using pliers to grip the wire, pull it out of the cable
from the connector end. Do not pull it from the
gun end.
f. Put the conductor cable back on wire drive unit
after the electrode has been removed.
g. Load a new coil of wire and feed it through the
cable as described in Loading Electrode Section.
OPEN ARC WELDING WITH A
CONSTANT CURRENT (formerly
variable voltage) POWER
SOURCE
Although a constant voltage (CV) power source
is recommended for Innershield
® and gas metal
arc welding (GMAW), satisfactory general p u r p o s e
w e l d i n g m a y b e o b t a i n e d u s i n g t h e LN-35 with
a constant current (CC) power source f o r n o n -
c r i t i c a l c o m m e r c i a l q u a l i t y m i l d s t e e l welding
applications.
While welding with a continuously fed electrode, weld
current variations are continuously taking place. There
are many causes for these variations, but
predominantly they occur due to changes in electrical
stickout (operator hand movements, nozzle tip contact
variations, etc.) and the dynamic metal transfer
characteristics of the process or procedure being used
(short arc, globular transfer, etc.).
When using a CV power source, these current
variations have essentially no effect on the welding
arc stability since CV power sources can provide a
wide range of weld current levels with virtually no
change in average arc voltage. These “flat slope” CV
power sources, therefore, provide the arc power
required to produce the best welding characteristics
and ease of operation for most open arc, constant wire
feed speed, welding processes.
LN-35
CYLINDER may explode if
damaged.
• Keep cylinder upright and
chained to support.
• Keep cylinder away from
areas where it may be
damaged.
• Never lift welder with cylinder attached
• Never allow welding electrode to touch cylin-
der.
• Keep cylinder away from welding or other live
electrical circuits.
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ARC RAYS can burn.
• Do not touch metal por-
tions of the LN-35 lead
Clamp when welding
power source is on.
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WARNING
WARNING