Operation. Lincoln Electric AutoPro 155S

A-3 230V INPUT


The AUTOPRO™ 155S is provided with a 230V cable, 6.0ft.(1.8m) in length, with a 50 Amp (NEMA 6-50P) plug molded onto the cord.

The rated output of the AUTOPRO™ 155S is available when connected to a 30A branch circuit. When con nected to a branch circuit with lower ampacity, lower welding current and duty cycle must be used. Other loads on the circuit and fuse/circuit breaker character istics will affect the available output.


A quick disconnect system using Twist-Mate™ cable plugs is used for the welding cable connections.

Refer to the following sections for more information on connecting the machine for operation of stick welding (SMAW) or TIG welding (GTAW).


• Keep the electrode holder and cable insulation in good condition.

• Do not touch electrically live parts or electrode with skin or wet clothing.

• Insulate yourself from work and ground.

• Turn the input line Switch on the AUTOPRO™ 155S “off” before connecting or disconnecting output cables or other equipment.



First determine the proper electrode polarity for the elec trode to be used. Consult the electrode data for this information. Then connect the output cables to the out put terminals of the machine for the selected polarity.

Shown here is the connection method for DC(+) welding.

(See Figure A.1) Connect the electrode cable to the (+) terminal and the work clamp to the (-) terminal. Insert the connector with the key lining up with the keyway and rotate approxi mately 1/4 turn clockwise. Do not over tighten.

For DC(-) welding, switch the cable connections at the machine so that the electrode cable is connected to (-) and the work clamp is connected to (+).


Electrode Holder Work Cable


Work Clamp


This machine does not have a built in Gas Solenoid so a one piece gas valve TIG Torch is required. A K960-2 Twist-mate TIG Torch adapter is also required.

Refer to the accessories section for more information about TIG Torches and required Twist-mate adapter.

Most TIG welding is done with DC(-) polarity shown here. If DC(+) polarity is necessary switch the cable connections at the machine. (See Figure A.2) Connect the torch cable to the (-) terminal of the machine and the work clamp to the (+) terminal.

Insert the connector with the key lining up with the keyway and rotate approximately 1/4 turn clockwise.

Do not over tighten. Finally, connect the Twist-mate adapter gas hose to the gas regulator on the cylinder of gas to be used.


Work Cable Work Clamp Gas hose to bottle Gas Valve to TIG Torch Twist-mate Adapter K-960-2



OPERATION Read and understand this entire section before operating your machine.




The AUTOPRO™ 155S is rated at 150 amps at 30% duty cycle on a ten minute basis. It is capable of high er duty cycles at lower output currents. If the duty cycle is exceeded, a thermal protector will shut off the output until the machine cools.


The AUTOPRO™ 155S is recommended for the fol lowing Electrode Types and Diameters: • Do not touch electrically live parts such as output terminals or internal wiring.

• Insulate yourself from the work and ground.

• Always wear dry insulating gloves.


FUMES AND GASES can be dangerous.

ELECTRODE SIZE TYPE 5/64 (2.0) 3/32 (2.4) DIA.


(mm) 1/8 (3.2) 5/32 (4.0)

• Keep your head out of fumes.

• Use ventilation or exhaust to remove fumes from breathing zone.


WELDING, CUTTING and GOUGING SPARKS can cause fire or explosion

• Keep flammable material away.

• Do not weld, cut or gouge on contain ers that have held combustibles.

----------------------------------------------------------- Fleetweld 37 (E6013) Fleetweld 35 (E6011) Excalibur 7018 MR (7018)

• • • • • • • •


The AUTOPRO™ 155S is not recommended for pipe thawing.

ARC RAYS can burn.

• Wear eye, ear and body protection.

----------------------------------------------------------- Only qualified personnel should operate this equip ment. Observe all safety information throughout this manual.



The AUTOPRO™ 155S is a 150 amp arc welding power source which utilizes single phase input power to produce constant current output. The welding response of this Inverter has been optimized for stick (SMAW) and TIG (GTAW) welding.




(See Figure B.1)

1. Output Current Knob:

Potentiometer used to set the output current used during welding. Set the output according to the type and size of electrode.

2. Power Switch:

Turns ON / OFF the input power to the machine.

3. Welding Mode Switch:

Controls the welding mode of the machine: Select Stick welding or Lift TIG welding.

• Stick (SMAW): • Lift TIG (GTAW): When the mode switch is in the Lift TIG position, the stick welding functions are disabled and the machine is ready for Lift TIG weld ing. Lift TIG is a method of starting a TIG weld by first pressing the TIG torch electrode on the work piece in order to create a low current short circuit.

Then, the electrode is lifted from the work piece to start the TIG arc.

4. Thermal LED:

is again possible.

This indicator will turn on when the machine is overheated and the output has been disabled. This normally occurs when the duty cycle of the machine has been exceeded. Leave the machine on to allow the internal components to cool. When the indicator turns off, normal operation

5. Negative Quick Disconnect:

nector for the welding circuit.

Negative output con-

6. Positive Quick Disconnect:

Positive output con nector for the welding circuit.


(See Figure B.2)

7. Input cable:

This machine is provided with a plugged input cord. Connect it to input receptacle.

8. Fan FIGURE B.2



4 8 2 1 7 3 5 6 AUTOPRO™ 155S


(See Figure B.3)




This figure closely resembles what is actually seen during welding. The “arc stream ʼʼ is seen in the middle of the figure. This is the electric arc created by the electric current flowing through the space between the end of the electrode and the work.

Current flows through the electrode cable and elec trode holder to the electrode and across the arc. On the work side of the arc, the current flows through the base metal to the work cable and back to the welding machine. The circuit must be complete for the current to flow. To weld, the work clamp must be tightly connected to clean base metal. Remove paint, rust, etc. as neces sary to get a good connection. Connect the work clamp as close as possible to the area you wish to weld. Avoid allowing the welding circuit to pass through hinges, bearings, electronic components or similar devices that can be damaged.

An electric arc is made between the work and the end of a small metal rod, the electrode, which is clamped in a holder and the holder is held by the person doing the welding. A gap is made in the welding circuit (see Figure B.3) by holding the tip of the electrode 1/16 1/8” away from the work or base metal being welded.

The electric arc is established in this gap and is held and moved along the joint to be welded, melting the metal as it is moved.

ELECTRIC ARC (Stick-Welding)

(See Figure B.4) Action that takes place in the electric arc.


The temperature of this arc is about 6000°F (3315°C), which is more than enough to melt metal. The arc is very bright, as well as hot, and cannot be looked at with the naked eye without risking painful injury. A very dark lens, specifically designed for arc welding, must be used with a hand or face shield whenever viewing the arc. The arc melts the base metal and actually digs into it, much as water through a nozzle on a gar den hose digs into the earth. The molten metal forms a pool or crater and tends to flow away from the arc.

As it moves away from the arc, it cools and solidifies.

A slag forms on top of the weld to protect it during cooling.

The function of the covered electrode is much more than simply to carry current to the arc. The electrode is composed of a core rod of metal with an extruded chemical covering. The core rod melts in the arc and tiny droplets of molten metal shoot across the arc into the molten pool. The electrode provides additional filler metal for the joint to fill the groove or gap between the two pieces of the base metal. The cover ing also melts or burns in the arc. It has several func tions. It makes the arc steadier, provides a shield of smoke-like gas around the arc to keep oxygen and nitrogen in the air away from the molten metal, and provides a flux for the molten pool. The flux picks up impurities and forms the protective slag.


Insert the bare part of the electrode into the electrode holder jaws and connect the work clamp to the weld ing piece. Make sure to have good electrical contact. 1. Turn the welder on. 2. Lower your welding helmet to protect your face and eyes.

3. Strike the electrode at the work point on the work piece as if striking a match. Do not hit the electrode on the workpiece, which will damage the stick elec trode and make striking an arc difficult. Scratch the electrode slowly over the metal and you will see sparks. While scratching, lift the electrode 1/8" (3.2mm) and the arc will establish.


If you stop moving the electrode while scratch ing, the electrode will stick.


Most beginners try to strike the arc by a fast jabbing motion down on the plate. Result: They either stick or their motion is so fast that they break the arc immediately.




4. Immediately after striking the arc try to maintain a distance from the workpiece that is equivalent to the diameter of the electrode used. Maintain this distance as constantly as possible during the weld.

Whenever possible, weld from left to right (if right handed). Hold the electrode at a slight angle as shown. (See Figure B.5)


8. Turn the machine off and remove the stub by open ing the jaws of the electrode holder and insert a new electrode.


The welded work piece and electrode stub are hot after welding. Allow them to cool down before touching or use pliers to move. Always make sure the welder is turned off before set ting down the Electrode Holder.


TIG Welding (Tungsten Inert Gas Welding)

5. As the electrode burns off the electrode must be fed to the work to maintain correct arc length. The easi est way to tell whether the arc has the correct length is by listening to its sound. A nice, short arc has a distinctive, “crackling” sound, very much like eggs frying in a pan. The incorrect, long arc has a hollow, blowing or hissing sound. 6. The important thing to watch while welding is the puddle of molten metal right behind the arc. Do NOT watch the arc itself. It is the appearance of the puddle and the ridge where the molten puddle solidifies that indicate correct welding speed. The ridge should be approximately 3/8" (9.5mm) behind the electrode. (See Figure B.6)


Most beginners tend to weld too fast, resulting in a thin, uneven, “wormy” looking bead. They are not watching the molten metal.




For general welding it is not necessary to weave the arc; neither forwards and backwards nor sideways. Weld along at a steady pace. You will find it When welding on thin plate, you will find that you will have to increase the welding speed, whereas when welding on heavy plate, it is necessary to go more slowly in order to get good penetration.

7. Once the electrode is burned down move the elec trode quickly from the weld to extinguish the arc.


This machine is capable of direct current (DC) TIG welding which is suitable for hard metals such as steel, stainless steel, copper & brass. The TIG process is good for welding thin materials requiring very good cosmetic appearance with low heat input and low spatter. TIG welding uses a tungsten elec trode which delivers electrical current to the work piece by way of an electric arc. Unlike stick welding in which the electrode is consumed in the arc, the tung sten electrode is not consumed. Instead filler metal is added to the weld by manually dipping a filler rod into the weld puddle. TIG welding requires a higher skill level than stick welding and practice is required to master the technique. For best results a TIG welding class is suggested or obtaining a book on how to TIG weld.

TIG welding also requires 100% Argon shielding gas to shield the arc, preventing porosity in the weld. This is different than stick welding which has a coating on the electrode to produce its own shielding. In addi tion, a gas regulator, a manual gas valve TIG torch, torch parts kit, torch adapter and filler metal are required. Refer to the accessories section of this manual for an appropriate optional TIG torch, parts kit and torch adapter. A gas regulator, filler metal and a bottle of shielding gas are readily available from a welding gas distributor.

Figure B.7 shows the basic TIG welding set-up:



B-5 Making a TIG Weld:


1. Connect the work cable to the positive “+” output terminal.

2. Connect the TIG torch to the negative “-“ output ter minal.

3. Connect the gas line from the TIG torch adapter to the gas regulator connected to the gas bottle. 4. Open the gas valve on the gas bottle and adjust the gas regulator to approximately 20-30 cfm.

5. Set the amperage based on material thickness: Steel Thickness (1/16”) 1.6mm

(1/8”) 3.2mm

(3/16) 4.8mm

Amperage Setting 60-90 Amps 75-120 Amps 125-150 Amps 6. Turn machine on.

7. Turn the gas valve on the torch to start shielding gas flowing.

8. Touch the tungsten to the work piece and pause for a second.

9. Slowly lift the tungsten off the work piece to estalish the arc. (Note: Rocking the torch back onto the ceramic shielding cup is an easy way to do this steadily.) 10. With the torch pointed in the direction of travel angled about 75 degrees to the work piece slowly move the torch in the direction of travel. Maintain about a 1/4” distance from the tungsten to the work piece while moving. Apply filler metal to the weld puddle by dipping the filler rod into the weld puddle allowing it to melt off and being careful not to touch the filler metal to the tungsten electrode.

11. At the end of the weld lift the TIG torch quickly away from the work piece to break the arc.

12. Turn off torch gas valve.

13. Turn machine off.


For more detailed information about TIG welding order “Gas Tungsten Arc Welding Guide Book (JFLF-834)” from the James F. Lincoln Arc Welding Foundation.




Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project