Lincoln Electric NA-3S, Service Manual, Page: 56 / 110

MAINTENANCE
D-3 D-3
NA-3 AND NA-4
The PC board power supply fuse, shown in
Figure D.2, is a 3/10 Amp fuse. It is located
on the control PC board and is designed to
protect the DC-regulated power supply from
overload. This fuse will blow if a PC board
component fails and overloads the 24 VDC
power supply. A second 3/10 Amp fuse is
added to the control board on newer models
to protect the board against faulted remote
switches.
FIGURE D.3 – WIRE DRIVE
MOTOR GEAR BOX.
WELDING HEAD
WIRE DRIVE GEAR BOX
Once a year, recoat all gear teeth with a
non-fluid molydisulfide grease such as
Non-Fluid Oil Corporation’s A-29 Special/
MS Lubricant. For access to the gears in the
first chamber, remove the adapter plate and
motor assembly as shown in Figure D.3. To
lubricate the gears in the second chamber,
remove one of the pipe plugs and feed
grease until it comes in contact with the
bevel gear teeth. Then, rotate the output
shaft by hand until all teeth are lubricated.
WIRE DRIVE MOTOR
Periodically inspect the wire drive motor
brushes, Figure D.3. Replace the brushes
as needed.
PIPE
PLUG
ADAPTER
PLATE AND
MOTOR
ASSEMBLY
HEX HEAD
SCREW
FIRST
CHAMBER
WIRE DRIVE
GEARBOX
SECOND
CHAMBER
SLOT HEAD
SCREW
DRIVE MOTOR
BRUSH ACCESS