Controls And Settings - Lincoln Electric SVM138-A Service Manual

B-5

CONTROLS AND SETTINGS

Operator controls for LN-9 GMA models are shown in
Figure B.3. Controls for LN-9F models are shown in
Figure B.4. Refer to these figures and the following
descriptions of the controls.
ELECTRODE POLARITY SWITCH: The polarity
switch is located inside the wire drive section on the
LN-9 GMA model and on the front panel of both the
LN-9F GMA 2-Roll and 4-Roll control box. Set the
switch to the same polarity as the electrode lead con-
nection to the power source. If the switch is not set
for the correct polarity, the wire feeder will stop weld-
ing shortly after the arc is struck. See the topic
"Automatic Shutdown" later in this section of the
manual.
WIRE FEED DIRECTION SWITCH: The direction
switch is located inside the wire drive section on the
LN-9 GMA model and on the front panel of both the
LN-9F GMA 2-Roll and 4-Roll control box. This switch
permits the wire to be fed in either direction when the
trigger is pressed or when using the cold inch switch
feature of the K418 and K419 options. Be sure this
switch is set for forward feed when you are ready to
weld.
OPERATION
HOT-COLD TRIGGER INTERLOCK SWITCH: This
switch is located on the front rail on the LN-9 GMA
model and on the front panel of both the LN-9F GMA
2-Roll and 4-Roll control box. The three-position
switch serves a dual purpose:
1. "Hot-Cold" Wire Feed - In the center position the
wire will be electrically cold when feeding with the
gun trigger. In either the up or down positions the
wire will be "hot" when feeding with the gun trigger.
2. Trigger Interlock Function - In the down position
the trigger interlock will be OFF, allowing the gun
trigger to function in the normal mode. This stops
wire feed and welding when the trigger is released.
In the up position the trigger interlock will be ON.
The trigger interlock feature functions as follows:
a) When you are not welding, the trigger will function
in the normal mode, which feeds only when the
trigger is closed.
b) Once the welding arc has been struck, the gun trig-
ger may be released. Welding will continue until
one of the following occurs:
• The arc is extinguished by quickly pulling the gun
away from the work.
or
• The trigger is again depressed and released.
(This feature is not on earlier versions unless the
L7265-1 PM Power Board has been replaced
with a superceded version.)
LN-9 GMA Wire Feeder
B-5