Lincoln Electric NA-3 Service Manual page 39

B-10
6. Set the "Contactor and Electrode
Back Up Time Delay" on the inner
control panel to prevent crater
sticking and to provide the stopping
characteristics required by the
application. For initial test welds, set
it to "5".
7. Straighten the first 6 in. (152.40 mm)
of the electrode and push it through
the wire straightener to the drive rolls.
Press the "Inch Down" button and
feed the electrode down through the
nozzle. Adjust the wire straightener
hand wheel. With contact nozzles
installed, except for the K231 Contact
Nozzle, adjust the hand wheel until
the electrode is straight as it comes
out of the nozzle. Do not completely
straighten the wire when using the
K231 Contact Nozzle because the
nozzle relies on the small curvature
of the electrode for proper electrical
contact within the contact tip.
8. Set the travel speed as specified by
the procedures. With the wire speed
"Travel" switch set to "Hand Travel,"
the travel runs without welding,
permitting accurate measurements of
travel speed. When using a Lincoln
Electric travel carriage, adjust the
speed with the rheostat and the
direction with the toggle switch on the
carriage control panel.
9. Connect the work lead to the work or
a suitable piece of scrap. Clip the end
of the electrode to a sharp point.
OPERATING INSTRUCTIONS
NA-3 AND NA-4
WARNING
When using an open arc process, it is
necessary to use correct eye, head, and
body protection.
10. Make a test weld and adjust the wire
feeder "Voltage Control" and "Current
Control" until the meters indicate the
output specified by the procedure.
11. Make several test welds and readjust
the starting and stopping controls in
the following order:
a. Set the "Inch Speed" control for
optimum arc striking. If using long
stickout techniques, see the
IM278 operating manual on using
the Linc-Fill extension.
TM
b. If installed, adjust the "Start
Controls" to set the welding
procedures during the first 0 to 3
seconds of welding in order to
provide the bead size, penetra-
tion, or other factors as needed
for the application.
c. If installed, adjust the "Crater
Controls" to set the welding
procedures during the first 0 to 3
seconds after the "Stop" button is
pressed in order to provide the
bead size or to fill the crater as
needed for the application.
d. Set the "Contactor and Electrode
Back Up Time Delay" to provide
the stopping characteristics
needed.
B-10