Instructions to Enter Slow RUN-IN

B-8	OPERATION	B-8

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

FAST OR SLOW RUN-IN MODE SELECTION,

(When Timer Option is not installed)

The POWER MIG 255C 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.

1.Turn power OFF on front panel of POWER MIG 255C.

2.Turn the wire feed speed dial to minimum, fully coun- terclockwise.

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

4.The display will read "SLO run".

INSTRUCTIONS TO ENTER FAST RUN-IN

1.Turn power OFF on front panel of POWER MIG 255C.

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 POWER MIG 255C.

4.The display will read "FAS run".

NOTE:Arc starting characteristics may be effected when using the fast run-in mode since optimum start- ing 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.

It is not necessary to repeat either of the above procedures each time the unit is powered up. The unit will remember the run-in mode from the previous

power down and return you to that same state upon your next power up. Thus, you need only perform one of the above procedures when you want to change the run-in mode.

MAKING A WELD

1.Check that the electrode polarity is correct for the process being used, then turn the power switch ON.

2.Set desired arc voltage and wire speed for the particular electrode wire, material type and thickness, and gas (for GMAW) being used. Use the Application Chart on the door inside the wire compartment as a quick reference for some common welding procedures.

3.If Timer Kit is installed, select the desired mode as described in "Operating Instructions for Timer Kit" in the Accessories section. Refer to the Accessories section for additional welding information pertaining to Spot mode. That chart is also in this manual as

Figure B.5.

4.Press the trigger to feed the wire electrode through the gun and cable and then cut the elec-trode within approximately 3/8" (10 mm) of the end of the contact tip [3/4" (20 mm) Outershield®].

NOTE: If set for slow run-in when the trigger is pulled, the wire feeder feeds wire at low speed regardless of the set wire feed speed until the welding arc starts or 1 second has elapsed. This feature enhances starting and makes it easier to set the stickout. The 1 second limit permits high speed loading of the gun and cable. To change run-in mode, see "Setting Run-In Speed" in this section, if the Timer Kit is not installed, or Timer Kit Operation section if installed.

5.If welding gas is to be used, turn on the gas supply and set the required flow rate (typically 25-35 CFH; 12-16 liters/min).

6.When using Innershield electrode, the gas nozzle may be removed from the insulation on the end of the gun and replaced with the gasless nozzle. This will give improved visibility and eliminate the possibility of the gas nozzle overheating.

7.Connect work cable to metal to be welded. Work clamp must make good electrical contact to the work. The work must also be grounded as stated in "Arc Welding Safety Precautions".

POWER MIG 255C

OPERATION

(When Timer Option is not installed)