Operating Steps

B-7	OPERATION	B-7
	OPERATION

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SETTING IDLE ROLL PRESSURE

The idle roll pressure thumb screw is set at the factory backed out 2-1/2 turns from full pressure. This is an approximate setting. The optimum idle roll pressure varies with type of wire, wire diameter, surface condi- tions, lubrication, and hardness. As a general rule, hard wires may require greater pressure, and soft, or aluminum wire, may require less pressure than the fac- tory setting. The optimum idle roll setting can be deter- mined as follows:

1.Push the end of gun against a solid object that is electrically isolated from the welder output.

2.Press the gun trigger for several seconds.

a.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, run new wire through gun, and repeat steps 1 and 2.

b.If the drive roll slips, loosen the thumb screw on the conductor block and pull the gun cable forward about 6" (15 cm). 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, reinstall the gun cable, and repeat steps 1 and 2.

WARNING

Before operating the machine, be sure you have all the materials needed to perform the work. Be sure you are familiar with and have taken all possible safety precautions before starting the work. It is important that you follow these operating steps each time you use the machine.

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STARTING THE WELDER

1.Turn the POWER switch to ON. This illuminates the red LED pilot light.

2.Select the correct voltage and wire speed for the welding process required.

3.Operate the gun trigger for welder output and to energize the wire feeder motor.

NOTE: When the POWER SWITCH is ON, the fan motor is thermostatically controlled to provide cooling for the transformer and other components only when the machine needs cooling. When the machine does not require fan cooling the fan does not run, such as when first turned on, when welding at low current, or at low duty cycle procedures.

CHANGING RUN-IN MODE

FAST OR SLOW RUN-IN MODE

SELECTION

The WIRE-MATIC 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 2.0 seconds, whichever occurs first. After which it will accelerate to the preset wire feed speed.

INSTRUCTIONS TO ENTER SLOW RUN-IN MODE

1.Turn power OFF on front panel of Wire-Matic 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 Wire-Matic 255.

4.The gas solenoid will actuate two times to signal that the unit has entered the slow run-in mode (the gun trigger need only be closed until the first gas solenoid actuation is heard).

INSTRUCTIONS TO ENTER FAST RUN-IN MODE

1.Turn power OFF on front panel of Wire-Matic 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 Wire-Matic 255.

4.The gas solenoid will actuate four times to signal that the unit has entered the fast run-in mode (the gun trigger need only be closed until the first gas solenoid actuation is heard).

Lincoln Electric SVM 119-A service manual Operating Steps, Setting Idle Roll Pressure

Models: SVM 119-A

OPERATION