Lincoln Electric NA-3S, Service Manual, Page: 35 / 110

OPERATING INSTRUCTIONS
B-6 B-6
NA-3 AND NA-4
OPTIONAL ELECTRONIC
VOLTMETER OPERATION
Set the desired arc voltage on the meter dial
and start to weld. The green light glows
when actual voltage matches the preset
voltage. Either red light will glow when the
welding voltage is higher or lower than the
preset voltage. Adjust the “Voltage Control”
selector in the appropriate direction until the
green light glows. The NA-4 only welds with
a constant current AC power source. Make
sure the “CV-CC” switch on the constant
current PC board inside the control box is
always set on “CC” and the constant current
board jumper is on the correct pin.
When Innershield
®
welding, connect the
jumper on the back of the meter between
A and B. The red lights will glow when the
welding voltage is 1/2 volt above or below
the preset voltage.
When submerged arc welding, connect the
jumper between B and C. The red lights will
glow when the welding voltage is 1 volt
above or below the preset voltage.
SETTING FOR CV OR CC
POWER SOURCES
The NA-3N welds only with a constant
voltage (CV) power source. This machine
can be converted for constant current (CC)
welding by installing the proper parts.
The NA-3S welds with either a CV or CC
power source. Set the equipment for either
“CV” or “CC” as appropriate per the
following:
1. If using a multi-process power source,
set it up per the instructions in the
operating manual shipped with the
power source.
2. Turn the input power off and open the
inner panel. Set the “CV-CC” switch
located on the constant current PC
board inside the control box as shown
in Figure B.5. When using an RS3
power source with the triangle plate
(for major voltage adjustments), the
constant current board jumper must
be on Pin L.
3. There are two nameplates on top of
each other on the front of the wire
feeder control box. Make sure the
correct nameplate for the power
source being used is on top.
4. If the optional start controls or crater
controls PC boards are installed,
make sure the correct nameplates for
the power supply being used are on
top.
L
CV
CC
H
CONSTANT
CURRENT
PC BOARD
CV-CC
SWITCH
CONSTANT
CURRENT
BOARD
JUMPER
FIGURE B.5 – CV-CC SWITCH.