Lincoln Electric PM 255 specifications Feeding Wire Electrode, Idle Roll Pressure Setting

PM 255

B-4 OPERATION B-4

FEEDING WIRE ELECTRODE

WARNING

When triggering, the electrode and drive mecha- nism are electrically “hot” relative to work and ground and remain “hot” several seconds after the gun trigger is released.

NOTE: Check that drive rolls, guide plates and gun parts are proper for the wire size and type being used. Refer to Table C.1 in Accessories section.

1.Turn the Readi-Reel or spool until the free end of the electrode is accessible.

2.While securely holding the electrode, cut off the bent end and straighten the first six inches. (If the electrode is not properly straightened, it may not feed properly through the wire drive system).

3.Release the pressure on the idle roll by swinging the adjustable pressure arm down toward the back of the machine. Lift the cast idle roll assembly and allow it to sit in an upright position. Leave the outer wire guide plate installed. Manually feed the wire through the incoming guide bushing and through the guide plates (over the drive roll groove). Push a sufficient wire length to assure that the wire has fed into the gun and cable assembly without restriction. Reposition the adjustable pressure arm to its origi- nal position to apply pressure to the wire.

4.Press gun trigger to feed the electrode wire through the gun.

IDLE ROLL PRESSURE SETTING

The idle roll pressure adjustment knob is set at the factory at the #2 hash mark. This is an approximate setting. The optimum idle roll pressure varies with type of wire, wire diameter, surface conditions, lubri- cation, and hardness. As a general rule, hard wires may require greater pressure, and soft, or aluminum wire, may require less pressure than the factory set- ting. The optimum idle roll setting can be determined as follows:

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 adjustment knob out 1/2 turn, run new wire through gun, and repeat above steps.

3.If the only result was drive roll slippage, loosen the adjustment knob on the conductor plate and pull the gun cable forward about 6" (15 cm). There should be a slight waviness in the expose wire. If there is not waviness, the pressure is too low. Tighten the adjustment knob 1/4 turn, reinstall the gun cable and repeat the above steps.

SETTING RUN-IN SPEED ON STAN- DARD POWER MIG FEEDER

FAST OR SLOW RUN-IN MODE SELECTION, (When Timer Option is not installed)

The PM 255 is factory set for fast run-in mode where the wire feed will accelerate directly to the preset wire feed speed when the gun trigger is closed.

Slow run-in mode may also be selected, where it will initially feed wire at 50 IPM until output current is sensed or for 1.0 seconds, whichever occurs first. After which it will accelerate to the preset wire feed speed.

NOTE: See operating instructions for Timer Option Kit if it is installed, as it provides its own Run-in operation.

INSTRUCTIONS TO ENTER SLOW RUN-IN

1.Turn power OFF on front panel of PM 255.

2.Turn the wire feed speed dial to minimum, fully counterclockwise.

3.With the gun trigger closed, turn the power ON at the front panel of the PM 255.

4.The display will read “SLO run”.

INSTRUCTIONS TO ENTER FAST RUN-IN

1.Turn power OFF on front panel of PM 255.

2.Turn the wire feed speed dial to maximum, fully clockwise.

3.With the gun trigger closed, turn the power ON at the front panel of the PM 255.

4.The display will read “FAS run”.

NOTE:

Arc starting characteristics may be effected when using the fast run-in mode since optimum starting processes are being overridden.

On the initial trigger closure at power up, no output power or wire feed will be available until the trigger is opened and reclosed, regardless of wire feed speed dial setting.