Lincoln Electric NA-5NF, NA-5SF Ground Fault Fuse Protection, FAST-BLOW Fuse, Pipe Plug

D-3 MAINTENANCE D-3

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The 1/8 amp fast-blow fuse, shown in Figure D.3, on a voltage PC board built since 1983, protects the NA-5 circuitry from damage which may result from a ground or case faulted control lead. If the fuse blows, the NA-5 voltage sensing lead circuit will be opened (Refer to Automatic Shutdown in Section B, Operating Procedures) and the Troubleshooting Guide.

FIGURE D.3 – VOLTAGE BOARD FUSE

LOCATION.

1/8 AMP

FAST-BLOW

FUSE￿

NA-5 circuit common (#510). Such a condition typically exists when the NA-5 polarity connections are set for electrode negative.

WELDING HEAD

WIRE DRIVE GEAR BOX

Once a year, recoat all gear teeth with a non-fluid molydisulfide type 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.4.

FIGURE D.4 – WIRE DRIVE MOTOR

GEAR BOX.

DRIVE MOTOR

BRUSH ACCESS

HEX HEAD

SCREW

ADAPTER

PLATE AND

MOTOR

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PIPE PLUG

ASSEMBLY

FIRST

CHAMBER

WIRE DRIVE

Return

Return

-NA 5VOLTAGE

GROUND FAULT FUSE PROTECTION

GEARBOX

SECOND

CHAMBER

SLOT HEAD

SCREW

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A1/8 amp fast-blow fuse, shown in Figure D.3, is located on the voltage PC board. This fuse will protect the NA-5 circuitry from damage resulting from a ground or case faulted control lead when the arc voltage potential exists between ground and the

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.

NA-5