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Safety precautions, General maintenance, Drive rolls and guide plates – Lincoln Electric POWER MIG SVM157-A User Manual

Page 24: Contact tip and gas nozzle installation, Gun tubes and nozzles, Gun cable cleaning, Maintenance, Warning contact tip and gas nozzle installation

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MAINTENANCE

D-2

D-2

POWER MIG 200

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SAFETY PRECAUTIONS

ELECTRIC SHOCK can kill.

• Have an electrician install and

service this equipment.

• Turn the input power off at the

fuse box before working on
equipment

• Do not touch electrically hot

parts.

(READ THE SAFETY PRECAUTIONS IN
THE FRONT OF THIS MANUAL BEFORE
WORKING ON THIS MACHINE.)

GENERAL MAINTENANCE

In extremely dusty locations, dirt may clog the air pas-
sages causing the welder to run hot. Blow dirt out of
the welder with low-pressure air at regular intervals to
eliminate excessive dirt and dust build-up on internal
parts.

The fan motors have sealed ball bearings which
require no service.

DRIVE ROLLS AND GUIDE PLATES

After every coil of wire, inspect the wire drive mecha-
nism. Clean it as necessary by blowing with low pres-
sure compressed air. Do not use solvents for cleaning
the idle roll because it may wash the lubricant out of
the bearing. All drive rolls are stamped with the wire
sizes they will feed. If a wire size other than that
stamped on the roll is used, the drive roll must be
changed.

For instructions on replacing or changing drive roll, see
“Wire Drive Rolls” in Operation section.

WARNING

CONTACT TIP AND GAS NOZZLE
INSTALLATION

1. Choose the correct size contact tip for the electrode

being used (wire size is stenciled on the side of the
contact tip) and screw it snugly into the gas diffuser.

2. Screw the appropriate fixed gas nozzle fully onto

the diffuser. Either the standard .50" (12.7 mm)
flush nozzle or other optional flush or recessed
(spray arc) nozzle sizes may be used. (See Table
D.2
in this section.)

3. If using optional adjustable slip-on nozzles, see

Table D.2 in this section.

Be sure the nozzle insulator is fully screwed onto
the gun tube and does not block the gas holes in
the diffuser.

Slip the appropriate gas nozzle onto the nozzle
insulator. Either a standard .50" (12.7 mm) or
optional .62" (15.9 mm) I.D. slip-on gas nozzle
may be used and should be selected based on
the welding application.

* Adjust the gas nozzle as appropriate for the

GMAW process to be used. Typically, the con-
tact tip end should be flush to .12" (3.2 mm)
extended for the short-circuiting transfer process
and .12" (3.2 mm) recessed for spray transfer.

GUN TUBES AND NOZZLES

1. Replace worn contact tips as required.

2. Remove spatter from inside of gas nozzle and from

tip after each 10 minutes of arc time or as required.

GUN CABLE CLEANING

To help prevent feeding problems, clean cable liner
after using approximately 300 pounds (136 kg) of elec-
trode. Remove the cable from the wire feeder and lay
it out straight on the floor. Remove the contact tip from
the gun. Using an air hose and only partial pressure,
gently blow out the cable liner from the gas diffuser
end.