Start out Right
After you install your gas and opened the valves, spray soapy water on your hose, and connections look for leaks. Make sure your gun is seated correctly. Pull off the nozzle on your mig gun and clean the holes in the mixing nut. Cover the holes with electrical tape, press the purge button and spray your mig gun casing with soapy water and look for leaks. Now put your soapy water away and open up the LN-25 remove your wire and covers until you can see the gas tubing it is white, Hold the purge button and check for leaks. It is common for leaks to occur above the contact solenoid, because of the heat. Pull off the tape and make sure the gas is blasting out of the mixing nut when you pull the trigger. If no gas check the voltage 24v at the gas solenoid. if you have voltage replace solenoid. check voltage at the control board. no voltage replace board. If you have voltage fix or replace wires.
Once you have installed your wire (and wiper with the correct roller and tip of course) lay the ln-25 on its side with the mig gun stretched out straight. Now open the drive wheels, and move the wire by hand. If it does not move freely change your tip. If still does not move freely change your liner. I test this every day. Now close the the drive rolls and, loosen the drive tension nut. hold the gunâ€™s tip agents some wood to keep the wire from moving. Pull the trigger and tighten the drive tension nut until the wire bird nests. Loosen the the drive tension nut 1/2 turn. Fix bird nest. Pull the trigger and look at the voltage gauge. If it is below zero your polarity is not set right. If it is at zero your power or your clip is not connected.
Installing the Power Source
Connect the LN-25 to the electrode cable, and clip the clip to your work select CC or CV and it is ready to weld.
GOOD STUFF FROM THE MANUAL
The LN-25 is a lightweight portable semiautomatic wire feeder designed for â€œacross-the-arcâ€ operation without a control cable on most any DC welding power source. Simply connect the LN-25 to the electrode cable, clip it to Work and it is ready to weld, using up to 30 lb. coils or spools. The wire drive, controls and wire reel are fully enclosed in a rugged molded plastic case providing a compact and versatile welding package ideally suited to â€œon-the-goâ€ field welding applications in virtually any environment.
RECOMMENDED PROCESSES AND EQUIPMENT
When combined with the quality drive roll kits and accessories available for use with the LN-25, a versatile portable welding system can be provided to meet the specific needs of Innershield, submerged arc or gas metal arc welding applications within the wire feed capabilities of the LN-25. The LN-25 provides constant wire feed speed for use with constant voltage (CV) power sources, and arc sensing wire feed speed for use with constant current (CC) (formerly variable voltage) power sources. Wire speed is presettable on a dual-range calibrated dial. The power sources recommended for use with the LN-25 include the DC-250, -400, -600, CV-400 and R3S type transformer machines, and the SAM-400, 650 engine welders, as well as the SA-200, -250 or SAE-300, -400 with CV Adapter and Pulse Power 500 with K460-1 LN-25 Kit.Drive rolls for only cored electrode sizes are stencilled with a â€œCâ€ suffix to the wire sizes.Drive rolls for only solid electrode sizes are stencilled with an â€œSâ€ suffix to the wire sizes.Drive rolls for aluminum wire sizes are stencilled with an â€œAâ€ suffix to the wire sizes.
The LN-25 will handle up to 500 Amp 60% duty cycle welding currents. However, when equipped with a K443-2 Contactor, the LN-25 will handle up to 300 Amp 60% duty cycle.
(Factory installed on model Codes above 9218) The 40V DC analog voltmeter is mounted to the front control panel of the LN-25 and is connected to read the arc voltage between the LN-25 electrode cable connection and the work clip lead.
1. The Voltmeter will read zero if the LN-25 work clip lead is not connected to work, even if the electrode is electrically â€œhotâ€ to work.2. The Voltmeter will read below zero if the LN-25 polarity switch is not set to the same polarity as the electrode.3. The Voltmeter will read power source open circuit voltage when the gun trigger is open, even if the LN-25 is equipped with the internal contactor.
â€œELECTRODE POLARITYâ€ SWITCH
The polarity switch is located on the front panel of the LN-25 case. Set the switch to the same polarity as the electrode lead connection to the power source. If the switch is not set for the correct polarity, the wire feeder will not operate.
WIRE FEED MODE SWITCH
The CV-VV (CC) Wire Feed Mode switch is located inside the LN-25 case. The toggle switch extends from beneath the control box just above the wire drive. The forward â€œCVâ€ position provides constant wire feed speed mode for use with constant voltage (CV)welding power sources. The backward â€œVV (CC)â€ position provides arc-sensing wire feed speed mode for use with constant current (formerly variable voltage) welding power sources.
WIRE SPEED DIAL AND RANGE SWITCH
The Wire Speed control dial on the front panel of the LN-25 has two calibrated dial ranges selected by the HI-LO Dial Range switch. When switched to the LO range position, the constant wire feed speed (CV Wire Feed Mode) is set on the inside (white) or (red) dial range calibrated for 50 to 350 in/min. When switched to the HI range position, the constant wire feed speed (CV Wire Feed Mode) is set on the outside (black) or (blue) dial range calibrated for 50 to 700 in/min.
SPOOL BRAKE TENSION SETTING
Adjust the brake tension with the thumbscrew on the spindle hub until the reel turns freely, but with little or no overrun when wire feeding is stopped. Do not over tighten.
IDLE ROLL PRESSURE SETTING
The idle roll pressure is set at the factory backed out two turns from full pressure. This is an approximate setting. For small wire sizes and aluminum wire, the optimum idle roll pressure varies with type of wire, surface condition, lubrication and hardness. The optimum idle roll setting can be determined as follows:1. Press end of gun against a solid object that is electrically isolated from the welder output. Press the gun trigger for several seconds.2. If the wire â€œbird nests,â€ jams or breaks at the drive roll, the idle roll pressure is too great. Back the pressure setting out 1?2 turn, run new wire through gun, and repeat above steps.3. If the only result is drive roll slippage, shut off the power source, then loosen the gun cable clamping screw in the gearbox conductor block and pull the gun cable forward about six inches. There should be a slight waviness in the exposed wire. If there is no waviness, the pressure is too low. Increase the pressure setting 1?4 turn, lock the gun cable in place and repeat the above steps.
PRESETTING WIRE FEED SPEED
The LN-25 permits accurate presetting of the desired wire feed speed, before welding, in both CV and CC wire feed modes.
SETTING CONSTANT WIRE FEED SPEED (CV MODE)
a. Set Wire Feed Mode switch to CV position.b. Set Dial Range switch to LO position for wire feed speeds up to 350 in/min., or HI position for wire feed speeds over 350 in/min.c. Set Wire Feed dial to the desired wire feed speed on the selected calibrated dial range. The wire speed will remain constant at the value set, independent of arc voltage changes, as long as the arc voltage does not drop below the value per the chart below for the max. wire feed speed shown:Maximum Speed Minimum Arc Volts350 IPM 15V400 IPM 17V500 IPM 21V600 IPM 24V700 IPM 27V
SETTING ARC SENSING WIRE FEED SPEED (VV [CC] MODE)
When using a constant current (formerly variable voltage) power source, welding performance is improved using arc sensing wire feed speed (VV [CC]mode). In this wire feed mode the wire speed increases if arc voltage increases, and decreases if arc voltage decreases, but remains constant at any specific voltage level. The LN-25 permits accurate VV (CC) mode presetting of the desired wire feed speed, for the desired arc voltage to be used, by setting the Wire Speed dial in the following manner before welding:a. Set Wire Feed Mode switch to VV (CC) position. (Hl or LO Range)b. Referring to the graph located above the Mode switch (also shown in Figure B.3):1. Select the horizontal line representing the DESIRED IN/MIN. for the welding procedure. (Seeexample arrow line for 375 in/min.)2. Select the diagonal line representing the ARC VOLTS to be used for the welding procedure. (See example arrow line for 29 volts.)3. Determine the vertical line representing the CC WIRE SPEED SETTING where the above two lines cross. (See example arrow line for 450.)c. Set the Wire Speed dial to the value determined in Step (3) above (450 for example used). Use HI Dial Range if value to be set is over 350. The wire will feed at the DESIRED IN/MIN speed when the welding power source is set to the arc voltage to be used for the weld procedure (375 in/min. at 29V for example used).A chart representation of the VV (CC) wire speed setting graph is shown in Figure B.4, giving the Wire Speed dial setting required for the DESIRED IN/MIN and ARC VOLTS used for the welding procedures:LN-25 B-7 B-7
MAKING A WELD
The serviceability of a product or structure utilizing the LN-25 wire feeder is and must be the sole responsibility of the builder/user. Many variables beyond the control of The Lincoln Electric Company affect the results obtained in using the LN-25 wire feeder. These variables include, but are not limited to, welding procedure, plate chemistry and temperature, weldment design, fabrication methods and service requirements. The available range of the LN-25 wire feeder may not be suitable for all applications, and the builder/user is and must be solely responsible for welding settings.
a. Connect work cable to metal to be welded. Work cable must make good electrical contact to the work. The work must also be grounded as stated in â€œArc Welding Safety Precautions.â€b. Check that the LN-25 is properly connected to the power source for the polarity and process to be used, and appropriate power source settings are made for the procedure to be used. (Refer to power source operating and connection instructions.) NOTE: If the K431-1 Remote Output Control Kit or K624-1 42V Remote Control Module is installed but the LN-25 is to be used without the K432 Remote Control Cable Assembly, then the Remote Board harness plug must be removed from the 16-pin receptacle on the Control Board and the jumper plug (T13498-21) reinstalled. NOTE: If the K460-1 Pulse Power Adapter Kit is installed but the LN-25 is to be used without the K461 Pulse Power Control Cable Assembly, then the instructions for returning the unit to across the arc operation included with the Installation Instructions (L9636) must be followed.c. Place the LN-25 conveniently near the work area in a location to minimize exposure to weld spatter and to avoid sharp bends in the gun cable.d. Connect the LN-25 Clip Lead to work and set Polarity Switch to same polarity as electrode.e. Set WIRE FEED MODE switch to CV or CC, as appropriate for the power source, then set the proper DIAL RANGE and WIRE SPEED dial setting for the proper wire feed speed per the welding procedure:VV (CC) Speed Setting = Desired IPMX 35( Arc Volts)
OPERATION PROCEDURE AT END OF COIL
FIGURE B.4 VV(CC) WIRE SPEED SETTINGFor CV: Set dial to the calibrated IN/MINdesired. (Refer to Setting Constant Wire Feed Speed Section.) For CC: Set dial to value determined from the CC Wire Speed Graph for the DESIRED IN/MIN and ARC VOLTS to be used. (Refer to Setting Arc Sensing Wire Feed Speed Section.) NOTE: If procedure permits a range of acceptable arc voltage, use the middle of the range to determine proper WIRE SPEED setting.f. If using the optional Gas Flow Timer, set the desired PREFLOW TIME and POSTFLOW TIME.g. Be sure the proper contact tip for the wire size being used is in the gun, and the gun is safe from work contact. (Use the LN-25 insulated gun holder.)h. Turn on the welding power source, as well as the shielding gas supply (if used). Unless an optional output control or internal contactor is used, the electrode is electrically â€œhotâ€ when the power source is on. The gun trigger controls wire feed and gas supplied to the nozzle area (if used).When the wire on the reel is used up, the following procedure is to be followed for removing the old wire from the gun cable and loading a new reel.a. Shut off power source if a Remote Output Control Option or internal contactor is not used.b. Cut the end of the electrode off at the gun end. Do not break it off by hand since this puts a slight bend in the wire and makes it difficult or impossible to pull it back through the nozzle.c. Uncouple the gun conductor cable from the LN-25.d. Lay the cable out straight.e. Using pliers to grip the wire, pull it out of the cable from the connector end. Do not pull it from the gun end.f. Put the conductor cable back on wire drive unit after the electrode has been removed.g. Load a new coil of wire and feed it through the cable as described in Loading Electrode Section.a. Cut the electrode within approximately 3?8â€ of the end of the contact tip for solid wire and within approximately 3?4â€ of the extension guide for cored wire.b. Position electrode over joint. End of electrode should be slightly off the work.c. Lower welding helmet, close gun trigger, and begin welding. Hold the gun so the contact tip to work distance gives the correct electrical stickout as required for the procedure being used. NOTE: If the arc voltage is not within the proper procedure range adjust the power source output control. (The CC mode WIRE SPEED setting should not be changed from the preset procedure value for the proper arc voltage.)d. To stop welding, release the gun trigger and then pull the gun away from the work. Store the gun in the LN-25 insulated gun holder when not welding.
AUTOMATIC PROTECTION SHUTDOWN
The LN-25 control provides automatic electronic protection circuits which shut down the LN-25 for excessively high power source open circuit voltage or excessive motor overload.
If the power source open circuit voltage exceeds about 110-120 volts, the LN-25 will not operate until the power source voltage drops below about 102-110 volts.
MOTOR OVERLOAD SHUTDOWN
If excessive motor overload occurs (due to prolonged excessive feeding force, jammed drive rolls or shorted motor leads), the LN-25 will shut down within a few seconds after the overload occurs. The shutdown will reset automatically when the gun trigger is released, but will reoccur if the overload situation is not remedied.
DRIVE ROLLS AND GUIDE TUBES
After feeding every coil of wire, inspect the drive roll section. Clean it as necessary. Do not use a solvent for cleaning the idle roll because it may wash the lubricant out of the bearing. The drive roll, idle roll and guide tubes are stamped with the wire sizes they will feed. If a wire size other than that stamped on the rolls is to be used, the rolls and guide tubes must be changed. The drive rolls for .035 through .052 cored electrode and 1?16 through 5?64 electrode have a double set of teeth so they can be reversed for additional life. Drive rolls for .023 through .052 solid electrode and aluminum sizes have no teeth but use two grooves so they also can be reversed for additional life. See Wire Feed Drive Roll and Guide Tube Kits Section for roll changing instructions.
WIRE REEL SPINDLE
No routine maintenance required. Do not lubricate spindle.
WARNING SAFETY PRECAUTIONS CONTROL BOX
Every six months open and inspect the control section. The accumulated dirt should be gently blown off all of the electrical components. Be sure the air that is being used is dry. Check that lead plugs are secure in their receptacles.
WIRE DRIVE MOTOR AND GEAR BOX
Every year examine the gear box. Paint the gear teeth with molydisulfide filled grease. Lincoln specification E2322. Do not use a graphite grease. Check the motor brushes. Replace if they are worn down to 1?4â€™â€™ or less. When ordering feed motor brushes, give all information from the motor nameplate.
GUN AND CABLE MAINTENANCE
See IM manual provided with the gun and cableassembly.
1. Be sure all power to the LN-25 is shut off at the power source.2. Check that the module mounting plate is screwed securely to the side of the gearbox.3. Gently screw the module into the mounting plate until it just touches and stops against the rotating part inside the gearbox.4. Back the module out 1?2 turn, then snug the module lock nut without rotating the module position. Do not over tighten lock nut.
CALIBRATION OF LN-25 WIRE SPEED DIAL
Calibration of the LN-25 Wire Speed dial is achieved by proper mounting of the dial knob to the speed potentiometer shaft. Whenever the knob is removed, the dial is recalibrated as follows: NOTE: Knob set screw does not seat on shaft flat.1. Be sure the Wire Speed potentiometer mounting nut is securely tightened, then rotate the potentiometer shaft so its flat faces about to the 100 mark on the LO range calibrated dial.2. Set DIAL RANGE switch to LO and WIRE FEED MODE switch to CV position.3. Press gun trigger to feed wire and measure the wire feed speed (IN/MIN) using a Portable Digital Wire Feed Speed Meter (Lincoln K283). Take at least two readings to assure repeat able accuracy. Feed Speed Meter (Lincoln K283). Take at least two readings to assure repeatable accuracy. Electrode will be electrically â€œhotâ€. Do not allow fed wire to contact any metal common with welding work. An alternate means to measure wire feed speed is as follows:a. Cut wire off at the end of the gun tip.b. Press trigger to feed wire for exactly 30 seconds.c. Cut fed wire off at the end of the gun tip and accurately measure its length.d.Multiply the measured length by 2 to obtain the wire speed (IN/MIN).e.Repeat above steps to assure repeatable accuracy.4. Carefully slip speed knob onto potentiometer shaft so it points precisely to the wire speed measured in step 3, then secure the knob set screw without disturbing the position. Recheck by repeating step 3.
TROUBLESHOOTING PROBLEMS (SYMPTOMS)
No wire feed when gun trigger is pulledPOSSIBLE CAUSE1. Power source must be on and open circuit voltage (OCV) present at weld terminals.2. LN-25 work clip may not be connected.3. LN-25 polarity switch must match electrode polarity.4. Jumper plug on control or option board may be loose or missing.5. The power source O.C.V. must be above 15 VDC. But not more than 110 VDC.6. The gun trigger may be faulty.- Replace gun. Wire feeds for a short time but stops feeding. When gun trigger is released and retriggered wire feeding starts but stops again.1. The drive motor may be overloaded. Check the wire feeding system. EX. Drive roll tension, reel brake and gun cable liner. Wire feeds OK, but stubs or stops while welding.1. If the power source is a constant current type supply the arc voltage may be â€œdippingâ€ below 15 VDC causing the LN-25 to stop or hesitate.2. Connect a constant voltage type power supply to the LN-25.3. Make sure wire-feed mode switch (S3) is in the proper position.Rough wire feeding or wire not feeding but drive rolls turning.1. Gun cable kinked and/or twisted.2. Wire jammed in gun and cable.3. Incorrect size or installation of drive roll and guide tubes.4. Drive roll loose.5. Gun cable dirty.6. Worn drive roll.7. Electrode rusty and/or dirty.8. Worn nozzle or cable liner.9. Partially flashed or melted contact tip.10. Incorrect idle roll pressure.11. Wire reel brake tension set too high.Solenoid does not close when trigger is pulled or purge button is pressed.Wire feeds properly.1. Make certain that plugs J2 and J3 are connected to the control board securely. Variable or â€œhuntingâ€ arc. 1. Worn and/or melted contact tip -Replace.2. Worn work cable or poor work connection.3. Loose electrode connections. -Check for loose or faulty connections.4. Wrong electrode polarity for process being used. Weld porosity, narrow and ropey bead, or electrode stubbing into plate when welding.1. Contaminated weld joint or improper procedures. Clean joint and check procedure (wire speed and all voltage).Motor feeds but there is no wire feed speed control.1. Make sure all molex plugs and leads are securely connected to the control board.2. Check speed sensor
TEMPERATURE RANGE OPERATION:
- 40oC to +40oC (- 40oF to +104oF)STORAGE: – 40oC to +85o C (- 40oF to +185oF)
OPERATING ARC VOLTAGE
Constant Voltage (CV)or 15-40 VDC (110VDC Maximum OCV)Constant Current (CC)
Rated current without contactor 500 Amps 60% Duty CycleRated current with contactor 300 Amps 60% Duty Cycle
WIRE SPEED RANGE
50 â€“ 700 Inches Per Minute (IPM)RECOMMENDED ELECTRODE WIRE SIZES.023â€ to 1?16â€ SOLID STEEL WIRE.045â€ to 5?64â€ CORED WIRE.035â€ to 1?16â€ ALUMINUM WIREPHYSICAL DIMENSIONSHEIGHT WIDTH DEPTH WEIGHT(Handle Down) w/o Options 14 Inches 7.4 Inches 21 Inches 28 lbs (354 mm) (187 mm) (531 mm) (13 kg)’, ‘Lincoln LN-25 Care, Maintenance & Troubleshooting’, ‘
IDLE ROLL PRESSURE SETTING
The idle roll pressure is set at the factory backed out two turns from full pressure. This is an approximate setting. For small wire sizes and aluminum wire, the optimum idle roll pressure varies with type of wire, surface condition, lubrication and hardness. The optimum idle roll setting can be determined as follows:
1. Press end of gun against a solid object that is electrically isolated from the welder output. Press the gun trigger for several seconds.
2. If the wire â€œbird nests,â€ jams or breaks at the drive roll, the idle roll pressure is too great. Back the pressure setting out 1?2 turn, run new wire through gun, and repeat above steps.
3. If the only result is drive roll slippage, shut off the power source, then loosen the gun cable clamping screw in the gearbox conductor block and pull the gun cable forward about six inches. There should be a slight waviness in the exposed wire. If there is no waviness, the pressure is too low. Increase the pressure setting 1?4 turn, lock the guncable in place and repeat the above steps.