Lincoln Electric NA-3S, Service Manual, Page: 46 / 110

OPERATING INSTRUCTIONS
B-17 B-17
NA-3 AND NA-4
Changing the Stopping Sequence
To change the stopping sequence, turn the
AC power off at the power source, remove
the screw holding the inner panel and swing
the panel open. Change the connections
(older models) or switch positions (newer
models) on the logic board as follows in
Table B.7.
Optional Crater Controls PC Board
This option is recommended for roundabouts
and any other welds where the end overlaps
the start as well as applications in which the
ending bead size must be controlled or the
crater must be filled.
When the “Stop” button is pressed, the
machine welds at the current* and voltage
set by the “Crater Controls” until the time set
on the “Time in Seconds” control elapses.
The circuit then automatically switches to the
arc sequence described above.
*With the NA-4 and discontinued AC-1000 or AC-750
combination, the current is not adjustable.
TABLE B.7 – STOPPING SEQUENCE SWITCH POSITIONS.
When “Stop” Button
is Pressed Older Models Newer Models**
Feed motor stops and Lead #693 to pin #3
electrode burns back Lead #690 to pin #4
(standard)
Feed motor inches up and Lead #693 to pin #1
electrode burns back Lead #690 to pin #4
Feed motor inches up and Lead #693 to pin #1
contactor opens Lead #690 to pin #2
(no burnback)
2 3 4 1
Switch #2
2 3 4 1
Switch #2
Indicates switch in up position Indicates switch in down
position
Indicates switch position does not matter
THE POSITIONS OF SWITCH #1 DO NOT AFFECT THE STOPPING SEQUENCE.
2 3 4 1
Switch #2
**NOTE: