Feeding Electrode; Setting Idle Roll Pressure - Lincoln Electric IDEALARC SP-255 Service Manual

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FEEDING ELECTRODE

WARNING
When inching, the electrode and drive mechanism are
always "hot" to work and ground. The electrode re-
mains "hot" several seconds after the gun trigger is re-
leased.
____________________________________
NOTE: Check that the proper drive rolls and gun parts
are used for the wire size and wire type being used.
1. Turn the Readi-Reel or spool until the free end of
the electrode is accessible.
2. While tightly holding the electrode, cut off the bent
end and straighten the first six inches (152 mm).
Cut off the first inch (25 mm). (If the electrode is
not properly straightened, it may not feed properly
into the outgoing guide tube or welding gun causing
a "birdnest".)
3. Turn off weld timers by pressing the timers off key.
4. Push the wire through the ingoing guide tube, then
press the gun trigger and push the electrode into
the drive roll. If the electrode fails to thread itself
into the outgoing guide tube of the wire drive, open
the quick release idle roll arm, thread the electrode
manually, and reclose the arm.
5. Inch the electrode through the gun.
NOTE: If using the low speed starting feature of the SP-
255, the wire will feed at low speed for 2 seconds while
inching, then come up to the set speed.
6. Check that the welding process is set for the wire
type, diameter, and gas per instructions on name-
plate.

SETTING IDLE ROLL PRESSURE

The idle roll pressure wing screw is set at the factory
backed out 21/2 turns from full pressure. This is an ap-
proximate setting. The optimum idle roll pressure varies
with type of wire, wire diameter, surface condition, lu-
brication, and hardness. As a general rule, hard wires
may require greater pressure, and soft, or aluminum
wire, may require less pressure than the factory setting.
The optimum idle roll setting can be determined as fol-
lows:
OPERATION
1. Press end of gun against a solid object that is elec-
trically isolated from the welder output and press
the gun trigger for several seconds.
2. If the wire "birdnests", jams, or breaks at the drive
roll, the idle roll pressure is too great. Back the
thumb screw out 1/2 turn and run new wire through
the gun. Repeat above step.
3. If the drive roll slips, loosen the gun cable Fast-Mate
connection nut from the front of the SP-255. Pull
the gun cable forward about 6" (152 mm). There
should be a slight waviness in the exposed wire. If
there is no waviness, the pressure is too low.
Tighten the thumb screw 1/4 turn and lock the gun
cable in place. Repeat the above procedure.
IDEALARC SP-255
®
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