Lincoln Electric SP-250 service manual Feeding Electrode, Setting Idle Roll Pressure

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B-14		OPERATION		B-14
FEEDING ELECTRODE			2. If the wire "birdnests", jams, or breaks at the drive
			roll, the idle roll pressure is too great. Back the
	WARNING		wing screw out fi turn and run new wire through the
			gun. Repeat above step.
When inching, the electrode and drive mechanism are
			3. If the drive roll slips, loosen the gun cable Fast-
always “hot” to work and ground. The electrode
remains “hot” several seconds after the gun trigger is			Mate connection nut from the front of the SP-250.
released.			Pull the gun cable forward about 6".	There should
____________________________________			be a slight waviness in the exposed wire. If there
			is no waviness, the pressure is too low. Tighten the
NOTE: Check that the proper drive rolls and gun parts			wing screw 1/4 turn and lock the	gun cable in

are used for the wire size and wire type being used. place. Repeat the above procedure.

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. Cut off the first inch. (If the electrode is not properly straight- ened, it may not feed properly into the outgoing guide tube or welding gun causing a "birdnest".)

3.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.

4.Inch the electrode through the gun.

NOTE: Due to the low speed starting feature of the SP-250, the wire will feed at low speed for 2 seconds while inching, then come up to the set speed.

5.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 2fi turns from full pressure. This is an approximate setting. The optimum idle roll pressure varies with type of wire, wire diameter, surface condi- tion, lubrication, and hardness. As a general rule, hard wires may require greater pressure, and soft, or alu- minum wire, may require less pressure than the facto- ry setting. The optimum idle roll setting can be deter- mined 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.

IDEALARC SP-250