Lincoln Electric V250-S User Manual

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SVM124-A
INVERTEC V250-S
For use with machine Code Numbers 10102 to 10188
Safety Depends on You
NOT INSTALL, OPERATE OR REPAIR THIS EQUIPMENT WITHOUT READING THIS MANUAL AND THE SAFETY PRECAUTIONS CONTAINED THROUGHOUT. And, most
importantly, think before you act and be careful.
July, 1996
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World's Leader in Welding and Cutting Products Premier Manufacturer of Industrial Motors
SERVICE MANUAL
Sales and Service through Subsidiaries and Distributors Worldwide
22801 St. Clair Ave. Cleveland, Ohio 44117-1199 U.S.A. Tel. (216) 481-8100
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i

SAFETY

i
WARNING
CALIFORNIA PROPOSITION 65 WARNINGS
Diesel engine exhaust and some of its constituents are known to the State of California to cause can­cer, birth defects, and other reproductive harm.
The Above For Diesel Engines
ARC WELDING CAN BE HAZARDOUS. PROTECT YOURSELF AND OTHERS FROM POSSIBLE SERIOUS INJURY OR DEATH. KEEP CHILDREN AWAY. PACEMAKER WEARERS SHOULD CONSULT WITH THEIR DOCTOR BEFORE OPERATING.
Read and understand the following safety highlights. For additional safety information, it is strongly recommended that you purchase a copy of “Safety in Welding & Cutting - ANSI Standard Z49.1” from the American Welding Society, P.O. Box 351040, Miami, Florida 33135 or CSA Standard W117.2-1974. A Free copy of “Arc Welding Safety” booklet E205 is available from the Lincoln Electric Company, 22801 St. Clair Avenue, Cleveland, Ohio 44117-1199.
BE SURE THAT ALL INSTALLATION, OPERATION, MAINTENANCE AND REPAIR PROCEDURES ARE PERFORMED ONLY BY QUALIFIED INDIVIDUALS.
The engine exhaust from this product contains chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm.
The Above For Gasoline Engines
FOR ENGINE powered equipment.
1.a. Turn the engine off before troubleshooting and maintenance work unless the maintenance work requires it to be running.
____________________________________________________
1.b.Operate engines in open, well-ventilated areas or vent the engine exhaust fumes outdoors.
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1.c. Do not add the fuel near an open flame
welding arc or when the engine is running. Stop the engine and allow it to cool before refueling to prevent spilled fuel from vaporiz­ing on contact with hot engine parts and igniting. Do not spill fuel when filling tank. If fuel is spilled, wipe it up and do not start engine until fumes have been eliminated.
____________________________________________________
1.d. Keep all equipment safety guards, covers
and devices in position and in good repair.Keep hands, hair, clothing and tools away from V-belts, gears, fans and all other moving parts when starting, operating or repairing equipment.
____________________________________________________
1.e. In some cases it may be necessary to remove safety guards to perform required maintenance. Remove guards only when necessary and replace them when the maintenance requiring their removal is complete. Always use the greatest care when working near moving parts.
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1.f. Do not put your hands near the engine fan. Do not attempt to override the governor or idler by pushing on the throttle control rods while the engine is running.
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1.g. To prevent accidentally starting gasoline engines while turning the engine or welding generator during maintenance work, disconnect the spark plug wires, distributor cap or magneto wire as appropriate.
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1.h. To avoid scalding, do not remove the radiator pressure cap when the engine is hot.
ELECTRIC AND MAGNETIC FIELDS may be dangerous
2.a. Electric current flowing through any conductor causes localized Electric and Magnetic Fields (EMF). Welding current creates EMF fields around welding cables and welding machines
2.b. EMF fields may interfere with some pacemakers, and welders having a pacemaker should consult their physician before welding.
2.c. Exposure to EMF fields in welding may have other health effects which are now not known.
2.d. All welders should use the following procedures in order to minimize exposure to EMF fields from the welding circuit:
2.d.1.
Route the electrode and work cables together - Secure them with tape when possible.
2.d.2. Never coil the electrode lead around your body.
2.d.3. Do not place your body between the electrode and
work cables. If the electrode cable is on your right side, the work cable should also be on your right side.
2.d.4. Connect the work cable to the workpiece as close as
possible to the area being welded.
2.d.5. Do not work next to welding power source.
Mar ‘95
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SAFETY
ii
ELECTRIC SHOCK can kill.
3.a. The electrode and work (or ground) circuits are electrically “hot” when the welder is on. Do not touch these “hot” parts with your bare skin or wet clothing. Wear dry, hole-free
gloves to insulate hands.
3.b. Insulate yourself from work and ground using dry insulation. Make certain the insulation is large enough to cover your full area of physical contact with work and ground.
In addition to the normal safety precautions, if welding must be performed under electrically hazardous conditions (in damp locations or while wearing wet clothing; on metal structures such as floors, gratings or scaffolds; when in cramped positions such as sitting, kneeling or lying, if there is a high risk of unavoidable or accidental contact with the workpiece or ground) use the following equipment:
• Semiautomatic DC Constant Voltage (Wire) Welder.
• DC Manual (Stick) Welder.
• AC Welder with Reduced Voltage Control.
3.c. In semiautomatic or automatic wire welding, the electrode, electrode reel, welding head, nozzle or semiautomatic welding gun are also electrically “hot”.
3.d. Always be sure the work cable makes a good electrical connection with the metal being welded. The connection should be as close as possible to the area being welded.
3.e. Ground the work or metal to be welded to a good electrical (earth) ground.
ARC RAYS can burn.
4.a. Use a shield with the proper filter and cover plates to protect your eyes from sparks and the rays of the arc when welding or observing open arc welding. Headshield and filter lens should conform to ANSI Z87. I standards.
4.b. Use suitable clothing made from durable flame-resistant material to protect your skin and that of your helpers from the arc rays.
4.c. Protect other nearby personnel with suitable, non-flammable screening and/or warn them not to watch the arc nor expose themselves to the arc rays or to hot spatter or metal.
FUMES AND GASES can be dangerous.
5.a.Welding may produce fumes and gases hazardous to health. Avoid breathing these fumes and gases.When welding, keep your head out of the fume. Use enough ventilation and/or exhaust at the arc to keep
fumes and gases away from the breathing zone. When
welding with electrodes which require special ventilation such as stainless or hard facing (see instructions on container or MSDS) or on lead or cadmium plated steel and other metals or coatings which produce highly toxic fumes, keep exposure as low as possible and below Threshold Limit Values (TLV) using local exhaust or mechanical ventilation. In confined spaces or in some circumstances, outdoors, a respirator may be required. Additional precautions are also required when welding on galvanized steel.
3.f.
Maintain the electrode holder, work clamp, welding cable and welding machine in good, safe operating condition. Replace damaged insulation.
3.g. Never dip the electrode in water for cooling.
3.h. Never simultaneously touch electrically “hot” parts of electrode holders connected to two welders because voltage between the two can be the total of the open circuit voltage of both welders.
3.i. When working above floor level, use a safety belt to protect yourself from a fall should you get a shock.
3.j. Also see Items 6.c. and 8.
5.b.
Do not weld in locations near chlorinated hydrocarbon
coming from degreasing, cleaning or spraying operations. The heat and rays of the arc can react with solvent vapors form phosgene, a highly toxic gas, and other irritating products.
5.c. Shielding gases used for arc welding can displace air and
cause injury or death. Always use enough ventilation, especially in confined areas, to insure breathing air is safe.
5.d. Read and understand the manufacturer’s instructions for this
equipment and the consumables to be used, including the
material safety data sheet (MSDS) and follow your
employer’s safety practices. MSDS forms are available from
your welding distributor or from the manufacturer.
5.e. Also see item 1.b.
Mar ‘95
vapors
to
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iii
SAFETY
iii
WELDING SPARKS can cause fire or explosion.
6.a.
Remove fire hazards from the welding area.
If this is not possible, cover them to prevent
the welding sparks from starting a fire.
materials from welding can easily go through small cracks and openings to adjacent areas. Avoid welding near hydraulic lines. Have a fire extinguisher readily available.
6.b. Where compressed gases are to be used at the job site, special precautions should be used to prevent hazardous situations. Refer to “Safety in Welding and Cutting” (ANSI Standard Z49.1) and the operating information for the equipment being used.
6.c. When not welding, make certain no part of the electrode circuit is touching the work or ground. Accidental contact can cause overheating and create a fire hazard.
6.d. Do not heat, cut or weld tanks, drums or containers until the proper steps have been taken to insure that such procedures will not cause flammable or toxic vapors from substances inside. They can cause an explosion even been “cleaned”. For information, purchase “Recommended Safe Practices for the Containers and Piping That Have Held Hazardous Substances”, AWS F4.1 from the American Welding Society
(see address above).
6.e. Vent hollow castings or containers before heating, cutting or welding. They may explode.
6.f.
Sparks and spatter are thrown from the welding arc. Wear oil free protective garments such as leather gloves, heavy shirt, cuffless trousers, high shoes and a cap over your hair. Wear ear plugs when welding out of position or in confined places. Always wear safety glasses with side shields when in a welding area.
6.g. Connect the work cable to the work as close to the welding area as practical. Work cables connected to the building framework or other locations away from the welding area increase the possibility of the welding current passing through lifting chains, crane cables or other alternate cir­cuits. This can create fire hazards or overheat lifting chains or cables until they fail.
6.h. Also see item 1.c.
Remember that welding sparks and hot
though
they have
Preparation
for Welding and Cutting of
CYLINDER may explode if damaged.
7.a. Use only compressed gas cylinders containing the correct shielding gas for the process used and properly operating regulators designed for the gas and
pressure used. All hoses, fittings, etc. should be suitable for the application and maintained in good condition.
7.b. Always keep cylinders in an upright position securely chained to an undercarriage or fixed support.
7.c. Cylinders should be located:
•Away from areas where they may be struck or subjected to
physical damage.
• A safe distance from arc welding or cutting operations and
any other source of heat, sparks, or flame.
7.d. Never allow the electrode, electrode holder or any other electrically “hot” parts to touch a cylinder.
7.e. Keep your head and face away from the cylinder valve outlet when opening the cylinder valve.
7.f. Valve protection caps should always be in place and hand tight except when the cylinder is in use or connected for use.
7.g. Read and follow the instructions on compressed gas cylinders, associated equipment, and CGA publication P-l, “Precautions for Safe Handling of Compressed Gases in Cylinders,” available from the Compressed Gas Association 1235 Jefferson Davis Highway, Arlington, VA 22202.
FOR ELECTRICALLY powered equipment.
8.a. Turn off input power using the disconnect switch at the fuse box before working on the equipment.
8.b. Install equipment in accordance with the U.S. National Electrical Code, all local codes and the manufacturer’s recommendations.
8.c. Ground the equipment in accordance with the U.S. National Electrical Code and the manufacturer’s recommendations.
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Mar ‘95
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SAFETY
iv
PRÉCAUTIONS DE SÛRETÉ
Pour
votre propre protection lire et observer toutes les instruc­tions et les précautions de sûreté specifiques qui parraissent dans ce manuel aussi bien que les précautions de sûreté générales suivantes:
Sûreté Pour Soudage A L’Arc
1. Protegez-vous contre la secousse électrique:
a. Les circuits à l’électrode et à la piéce sont sous tension
quand la machine à souder est en marche. Eviter toujours tout contact entre les parties sous tension et la peau nue ou les vétements mouillés. Porter des gants secs et sans trous pour isoler les mains.
b. Faire trés attention de bien s’isoler de la masse quand on
soude dans des endroits humides, ou sur un plancher metallique ou des grilles metalliques, principalement dans
les positions assis ou couché pour lesquelles une grande partie du corps peut être en contact avec la masse.
c. Maintenir le porte-électrode, la pince de masse, le câble
de soudage et la machine à souder en bon et sûr état defonctionnement.
d.Ne jamais plonger le porte-électrode dans l’eau pour le
refroidir.
e. Ne jamais toucher simultanément les parties sous tension
des porte-électrodes connectés à deux machines à soud­er parce que la tension entre les deux pinces peut être le total de la tension à vide des deux machines.
f. Si on utilise la machine à souder comme une source de
courant pour soudage semi-automatique, ces precautions pour le porte-électrode s’applicuent aussi au pistolet de soudage.
5. Toujours porter des lunettes de sécurité dans la zone de soudage. Utiliser des lunettes avec écrans lateraux dans les zones où l’on pique le laitier.
6. Eloigner les matériaux inflammables ou les recouvrir afin de prévenir tout risque d’incendie dû aux étincelles.
7. Quand on ne soude pas, poser la pince à une endroit isolé de la masse. Un court-circuit accidental peut provoquer un échauffement et un risque d’incendie.
8. S’assurer que la masse est connectée le plus prés possible de la zone de travail qu’il est pratique de le faire. Si on place la masse sur la charpente de la construction ou d’autres endroits éloignés de la zone de travail, on augmente le risque de voir passer le courant de soudage par les chaines de lev­age, câbles de grue, ou autres circuits. Cela peut provoquer des risques d’incendie ou d’echauffement des chaines et des câbles jusqu’à ce qu’ils se rompent.
9. Assurer une ventilation suffisante dans la zone de soudage. Ceci est particuliérement important pour le soudage de tôles galvanisées plombées, ou cadmiées ou tout autre métal qui produit des fumeés toxiques.
10. Ne pas souder en présence de vapeurs de chlore provenant d’opérations de dégraissage, nettoyage ou pistolage. La chaleur ou les rayons de l’arc peuvent réagir avec les vapeurs du solvant pour produire du phosgéne (gas forte­ment toxique) ou autres produits irritants.
11. Pour obtenir de plus amples renseignements sur la sûreté, voir le code “Code for safety in welding and cutting” CSA Standard W 117.2-1974.
2. Dans le cas de travail au dessus du niveau du sol, se pro­téger contre les chutes dans le cas ou on recoit un choc. Ne jamais enrouler le câble-électrode autour de n’importe quelle partie du corps.
3. Un coup d’arc peut être plus sévère qu’un coup de soliel, donc:
a. Utiliser un bon masque avec un verre filtrant approprié
ainsi qu’un verre blanc afin de se protéger les yeux du rayonnement de l’arc et des projections quand on soude ou quand on regarde l’arc.
b. Porter des vêtements convenables afin de protéger la
peau de soudeur et des aides contre le rayonnement de l‘arc.
c. Protéger l’autre personnel travaillant à proximité au
soudage à l’aide d’écrans appropriés et non-inflamma­bles.
4. Des gouttes de laitier en fusion sont émises de l’arc de soudage. Se protéger avec des vêtements de protection libres de l’huile, tels que les gants en cuir, chemise épaisse, pantalons sans revers, et chaussures montantes.
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PRÉCAUTIONS DE SÛRETÉ POUR LES MACHINES À SOUDER À TRANSFORMATEUR ET À REDRESSEUR
1. Relier à la terre le chassis du poste conformement au code de l’électricité et aux recommendations du fabricant. Le dis­positif de montage ou la piece à souder doit être branché à une bonne mise à la terre.
2. Autant que possible, I’installation et l’entretien du poste seront effectués par un électricien qualifié.
3. Avant de faires des travaux à l’interieur de poste, la debrancher à l’interrupteur à la boite de fusibles.
4. Garder tous les couvercles et dispositifs de sûreté à leur
Mar. ‘93
Page 6
MASTER TABLE OF CONTENTS FOR ALL SECTIONS
vi
RETURN TO MAIN INDEX
INSTALLATION .......................................................................................................................SECTION A
TECHNICAL SPECIFICATIONS..................................................................................................A-2
SAFETY PRECAUTIONS ............................................................................................................A-3
SELECT SUITABLE LOCATION..................................................................................................A-3
INPUT CONNECTIONS...............................................................................................................A-3
INPUT VOLTAGE RECONNECT PROCEDURE.........................................................................A-4
OUTPUT CONNECTIONS...........................................................................................................A-5
OPERATION .......................................................................................................................SECTION B
SAFETY INSTRUCTIONS ...........................................................................................................B-2
GENERAL DESCRIPTION...........................................................................................................B-2
CONTROLS AND SETTINGS......................................................................................................B-3
CONSTANT CURRENT PROCESSES........................................................................................B-4
PARALLEL OPERATION.............................................................................................................B-5
OVERLOAD PROTECTION.........................................................................................................B-5
THERMAL PROTECTION............................................................................................................B-5
ACCESSORIES .......................................................................................................................SECTION C
OPTIONS / ACCESSORIES........................................................................................................C-2
CABLE PLUGS......................................................................................................................C-2
REMOTE CONTROLS ..........................................................................................................C-2
MAINTENANCE .......................................................................................................................SECTION D
INPUT FILTER CAPACITOR DISCHARGE PROCEDURE.........................................................D-2
ROUTINE MAINTENANCE..........................................................................................................D-3
FILTER CAPACITOR CONDITIONING ......................................................................................D-3
LOCATION OF MAINTENANCE COMPONENTS.......................................................................D-4
PAGE
THEORY OF OPERATION.........................................................................................................SECTION E
GENERAL DESCRIPTION...........................................................................................................E-2
INPUT LINE VOLTAGE................................................................................................................E-2
PRE-CHARGE AND PROTECTION............................................................................................E-3
MAIN TRANSFORMER................................................................................................................E-4
OUTPUT RECTIFICATION AND CONTROL...............................................................................E-5
PROTECTION CIRCUITS............................................................................................................E-6
INSULATED GATE BIPOLAR TRANSISTOR (IGBT) OPERATION............................................E-7
PULSE WIDTH MODULATION (PWM)........................................................................................E-8
TROUBLESHOOTING................................................................................................................SECTION F
HOW TO USE TROUBLESHOOTING GUIDE ......................................................................F-2
PC BOARD TROUBLESHOOTING PROCEDURES.............................................................F-3
TROUBLESHOOTING GUIDE...............................................................................................F-4
TEST PROCEDURES..........................................................................................................F-11
REPAIR AND REPLACEMENT PROCEDURES.................................................................F-43
RETEST AFTER REPAIR....................................................................................................F-77
ELECTRICAL DIAGRAMS.........................................................................................................SECTION G
PARTS MANUAL ................................................................................................................................P-244
INVERTEC V250-S
Page 7
SECTION-A-1
TECHNICAL SPECIFICATIONS..................................................................................................A-2
SAFETY PRECAUTIONS ............................................................................................................A-3
SELECT SUITABLE LOCATION..................................................................................................A-3
STACKING.............................................................................................................................A-3
TILTING.................................................................................................................................A-3
HIGH FREQUENCY PRECAUTIONS ...................................................................................A-3
INPUT CONNECTIONS...............................................................................................................A-3
GROUND CONNECTION......................................................................................................A-3
INPUT SUPPLY CONNECTIONS .........................................................................................A-3
POWER INPUT CONNECTION FOR 60HZ MACHINES......................................................A-3
POWER INPUT CONNECTION FOR 50/60 HZ MACHINES................................................A-4
INPUT FUSE AND SUPPLY WIRE .......................................................................................A-4
INPUT VOLTAGE RECONNECT PROCEDURE.........................................................................A-4
OUTPUT CONNECTIONS...........................................................................................................A-5
REMOTE CONTROL RECEPTACLE....................................................................................A-5
OUTPUT CABLES.................................................................................................................A-5
QUICK DISCONNECT PLUGS..............................................................................................A-5
INSTALLATION
TABLE OF CONTENTS
-INSTALLATION SECTION-
SECTION-A-1
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INVERTEC V250-S
Page 8
A-2
INSTALLATION
Technical Specifications - Invertec V250-S
INPUT
THREE PHASE SINGLE PHASE
Standard Input Current
Voltage
208/230/460 34/32/16 60Hz
200/220/400/440 35/33/18/17 50/60 Hz
THREE PHASE SINGLE PHASE
at Rated Output Model
208/230/460 60Hz 59/57/29 60Hz
200/220/400/440 50/60 Hz 58/58/30/30 50/60 Hz
RATED OUTPUT
Standard Input Current
Voltage
at Rated Output Model
A-2
Duty Cycle
(1)
Amps Rated Amps Model
35% Duty Cycle 250 30 60Hz 60% Duty Cycle 200 28-32 60Hz 100% Duty Cycle 165 26.5 60Hz 35% Duty Cycle 250 28†-30 50/60Hz 60% Duty Cycle 200 29-32 50/60Hz 100% Duty Cycle 165 26.5 50/60Hz
THREE PHASE SINGLE PHASE
Volts at
Welding Constant Open
Current Range
Circuit Voltage
1-250 Amps 65-80 VDC
RECOMMENDED INPUT WIRE AND FUSE SIZES
THREE PHASE SINGLE PHASE
Type 75°C
Type 75°C Copper
Fuse Input Copper Ground
(Superlag) Ampere Wire in Wire in
Input or Rating Conduit Conduit
Voltage Breaker on AWG (IEC) AWG (IEC)
Frequency
(2)
Size Nameplate Sizes Sizes
Duty Cycle
(1)
Amps Rated Amps Model
35% Duty Cycle 250 27†-30 60Hz 60% Duty Cycle 200 28-32 60Hz 100% Duty Cycle 165 26.5 60Hz 35% Duty Cycle 250 26†-30 50/60Hz 60% Duty Cycle 200 28-32 50/60Hz 100% Duty Cycle 165 26.5 50/60Hz
OUTPUT
Welding Constant Open
Volts at
Current Range
1-250 Amps 65-80 VDC
Fuse Input Copper Ground
(Superlag) Ampere Wire in Wire in
Input or Rating Conduit Conduit
Voltage Breaker on AWG (IEC) AWG (IEC)
Frequency
(2)
Size Nameplate Sizes Sizes
Circuit Voltage
Type 75°C Copper
Type 75°C
208/60 50 34 10 (6mm2) 10 (6mm2) 230/60 50 32 10(6mm2) 10 (6mm2) 460/60 30 16 10 (6mm2) 10 (6mm2)
200/50/60 50 35 10 (6mm2) 10 (6mm2) 220/50/60 50 33 10 (6mm2) 10 (6mm2) 400/50/60 30 18 10 (6mm2) 10 (6mm2) 440/50/60 30 17 10 (6mm2) 10 (6mm2)
(1) Based on a 10 min. period.
(2) Input voltage must be within ±10% of rated value. (3) For 1 phase use on 208 or 230 VAC input with output usage above 175A/60% or 200A/35%, the #10 input line cord supplied with the unit should be changed to a
#8 or larger conductor cord.
(†)
200 & 208VAC input may not meet NEMA/IEC specifications at 250 Amps.
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(3)
208/60
(3)
230/60
460/60 40 29 10 (6mm2) 10 (6mm2)
200/50/60 80 58 8 (16mm2) 10 (6mm2) 220/50/60 80 58 8 (16mm2) 10 (6mm2) 400/50/60 40 30 10 (6mm2) 10 (6mm2) 440/50/60 40 30 10 (6mm2) 10 (6mm2)
80 59 8 (10mm2) 10 (6mm2) 80 57 8 (10mm2) 10 (6mm2)
PHYSICAL DIMENSIONS
Height Width Depth Weight
15.0 in. 9.1 in. 19.7 in. 36 lbs. 381 mm 231 mm 500 mm 17 Kg
INVERTEC V250-S
Page 9
A-3
INSTALLATION
A-3
Read this entire installation section before you start installation.
SAFETY PRECAUTIONS
WARNING
ELECTRIC SHOCK can kill.
• Have an electrician install and ser­vice this equipment.
• Turn the input power off at the fuse box before working on equipment.
• Do not touch electrically hot parts.
• Be sure to discharge capacitors with the procedure outlined in the Maintenance Section of this manual before working in that area of the equipment.
---------------------------------------------------------------------
SELECT SUITABLE LOCATION
The Invertec V250-S will operate in harsh environ­ments. Even so, it is important that simple preventa­tive measures are followed in order to assure long life and reliable operation.
HIGH FREQUENCY PRECAUTIONS
If possible locate the V250-S away from radio con­trolled machinery. The normal operation of the V250-S may adversely affect the operation of RF con­trolled equipment, which may result in bodily injury or damage to the equipment.
INPUT CONNECTIONS
The Invertec V250-S should be connected only by a qualified electrician. Installation should be made in accordance with all local and national electric codes and the information detailed below.
GROUND CONNECTION
Ground per National Electrical Code for 60Hz machines connect the green lead to earth ground. For 50/60Hz machines connect the ground terminal marked located in the machine on the lower right side the base of the welder to earth ground.
INPUT SUPPLY CONNECTIONS
Be sure the voltage phase and frequency of the input power is as specified on the rating plate, located on the rear of the machine.
• The machine must be located where there is free cir­culation of clean air such that air movement in the back and out the front will not be restricted.
• Dirt and dust that can be drawn into the machine should be kept to a minimum. Failure to observe these precautions can result in excessive operating temperatures and nuisance shutdown.
• Keep machine dry. Shelter from rain and snow. Do not place on wet ground or in puddles.
STACKING
V250-S’s cannot be stacked.
TILTING
Place the machine directly on a secure, level surface or on a recommended undercarriage. The machine may topple over if this procedure is not followed.
Supply line entry provision is in the case rear panel.
POWER INPUT CONNECTION FOR 60HZ MACHINES
A 10 ft. power cord is provided and wired into the machine. Follow the power cord connection instruc­tions. Incorrect connection may result in equipment damage.
Single Phase Input:
per U.S. National Electrical Code. Connect black and white leads to power. Wrap red lead with tape to pro­vide 600V insulation.
Three Phase Input:
per U.S. National Electrical Code. Connect black, red and white leads to power.
Connect green lead to ground
Connect green lead to ground
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INVERTEC V250-S
Page 10
A-4
INSTALLATION
A-4
POWER INPUT CONNECTION FOR 50/60 HZ MACHINES
1. Connect terminal marked to earth ground
per National Electric Code.
2. Connect the supply lines to the line switch. Torque
to 3.0 Nm.
3. Install in accordance with all local and national
electric codes.
The Invertec V250-S 50/60 Hz machine is supplied with one cord connector. The cord connector provides a strain relief for the input power cord as it passes it through the rear access hole. The cord connector is designed for a cord diameter of 7.9 to 27.2mm (.310 to 1.070 in).
Strip away outer jacket of cord, trim fillers and insert conductors through cord connector. The jacketed por­tion of the cord must go through the cord connector. Tighten both connector screws.
INPUT FUSE AND SUPPLY WIRE
Refer to the beginning of this chapter for the proper fuse sizes and supply cable sizes.
• Fuse the input circuit with recommended super lag
fuses or delay type circuit breakers.
Technical Specifications
page at the
INPUT VOLTAGE RECONNECT PROCEDURE
When received directly from the factory, units are con­nected for the highest input voltage, 440 VAC for 50/60 Hz machines and 460 VAC for 60 Hz machines. If 440 or 460 VAC is the desired input, then the machine may be connected to the power system with­out any setup required inside the reconnect door. However, verify the connection with the following pro­cedure. For other voltages refer to the instructions located on the Reconnect Panel Access Door or fol­low the instructions below.
CAUTION
Failure to follow these instructions can cause immedi­ate failure of components within the welder.
------------------------------------------------------------------------
1. Open the access door on the right side of the machine.
2. For 200-230: Position the large switch to 200-230. For 380-460: Position the large switch to 380-460.
3. Move the “A” lead to the appropriate terminal. Refer to figure A.1 below.
• Install the proper fuse in the fuse holder in the main disconnect panel.
RECONNECT PROCEDURE
1. BE SURE POWER SWITCH IS OFF.
2. CONNECT LEAD 'A' TO DESIRED INPUT VOLTAGE RANGE.
440-460V
380-415V 220-230V 200-208V
3. POSITION SWITCH TO DESIRED INPUT VOLTAGE RANGE.
VOLTAGE=380-460V
THE LINCOLN ELECTRIC CO. CLEVELAND, OHIO U.S.A.
Figure A.1 Input Voltage Reconnect Instructions
'A'
IF MACHINE CEASES TO OPERATE (NO METER, NO FAN) AND THERE IS NO OTHER KNOWN FAILURE: CHECK FUSE; REPLACE WITH SPECIFIED FUSE.
.
Disconnect input power before inspecting or servicing machine.
.
Do not operate with wraparound removed.
.
Do not touch electrically live parts.
.
Only qualified persons should install, use or service this equipment.
VOLTAGE=200-230V
A
S21230
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INVERTEC V250-S
Page 11
A-5
INSTALLATION
A-5
OUTPUT CONNECTIONS
Refer to figure A.2 for the location of the 6 Pin Remote Receptacle and the Output Terminals.
SMAW
SMAW
6 PIN REMOTE RECEPTACLE
SOFT
REMOTE
GTAW
CRISP
LOCAL
-
THERMAL
A
120
85
OUTPUT
50
15
1
250
INVERTEC V250-S
+
HOT START
5
6
4
3
2
1
0
170
ARC FORCE
230
5
6
4
3
2
1
0
¤
I
O
7
8
9
10
7
8
9
10
S
QUICK DISCONNECT PLUGS
A quick disconnect system is used for the welding cable connections. The welding plug included with the machine is designed to accept a welding cable size of 1/0 to 2/0.
1. Remove 1 in. (25mm) of welding cable insulation.
2. Slide rubber boot onto cable end. The boot end may be trimmed to match the cable diameter. Soap or other lubricant will help to slide the boot over the cable.
BOOT
WELDING CABLE
25 mm
1 in.
TRIM
OUTPUT TERMINALS
FIGURE A.2 OUTPUT CONNECTIONS
REMOTE CONTROL RECEPTACLE
Remote control (K857), Arc start switch (K814), Hand amptrol (K963) and Foot amptrol (K870) connect directly to 6 pin amphenol on the front of the unit.
OUTPUT CABLES
Select the output cable size based on Table A.1.
TABLE A.1
Cable Sizes for Combined Length of Electrode and
Work Cable ( Copper Cable Rated at 75°C).
Length Cable Size up to 150 ft.(46m) 1/0 (50mm2) up to 250 ft.(72m) 2/0 (70mm2)
3. Slide the copper tube into the brass plug.
4. Insert cable into copper tube.
5. Tighten set screw to collapse copper tube. Screw
must apply pressure against welding cable. The top of the set screw will be well below the surface of the brass plug after tightening.
SET SCREW
BRASS PLUG
COPPER TUBE
6. Slide rubber boot over brass plug. The rubber
boot must be positioned to completely cover all electrical surfaces after the plug is locked into the receptacle.
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INVERTEC V250-S
Page 12
A-6
NOTES
A-6
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INVERTEC V250-S
Page 13
OPERATION
SECTION-B-1SECTION-B-1
TABLE OF CONTENTS
-OPERATION SECTION-
SAFETY INSTRUCTIONS ...........................................................................................................B-2
GENERAL DESCRIPTION...........................................................................................................B-2
OPERATIONAL FEATURES.................................................................................................B-2
WELDING CAPABILITY ........................................................................................................B-2
LIMITATIONS ........................................................................................................................B-2
CONTROLS AND SETTINGS......................................................................................................B-3
CONSTANT CURRENT PROCESSES........................................................................................B-4
MANUAL ARC WELDING (STICK)........................................................................................B-4
AIR CARBON ARC CUTTING...............................................................................................B-4
TIG WELDING.......................................................................................................................B-4
PARALLEL OPERATION.............................................................................................................B-5
OVERLOAD PROTECTION.........................................................................................................B-5
THERMAL PROTECTION............................................................................................................B-5
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INVERTEC V250-S
Page 14
B-2
OPERATION
B-2
Read and understand this entire section before operating your machine.
SAFETY INSTRUCTIONS
WARNING
ELECTRIC SHOCK can kill.
• 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.
• 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
GENERAL DESCRIPTION
The Invertec V250-S is a 250 amp arc welding power source that utilizes single or three phase input power, to produce constant current output. The welding response of this Invertec has been optimized for stick (SMAW) and TIG (GTAW).
OPERATIONAL FEATURES
The Invertec V250-S provides continuous total range output current adjustment, selectable welding modes and local or remote output control. Welding character­istics can be controlled via an arc force control. Additionally, starting characteristics can be adjusted via a “hot start” control.
WELDING CAPABILITY
The Invertec V250-S is rated at 250 amps, 35% duty cycle (based on a 10 minute cycle). It is also rated at 165 amps, 100% duty cycle, and 200 amps, 60% duty cycle.
LIMITATIONS
The V250-S is not recommended for pipe thawing. The V250-S should not be powered from the auxiliary
power supply of an engine welder. Special protection circuits may operate causing loss of output.
____________________________________
____________________________________
Only qualified personnel should operate this equip­ment. Observe all safety information throughout this manual.
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• Keep flammable material away.
• Do not weld, cut or gouge on
containers that have held com-
bustibles.
ARC RAYS can burn.
• Wear eye, ear and body protection.
INVERTEC V250-S
Page 15
B-3
OPERATION
B-3
CONTROLS AND SETTINGS
All operator controls and adjustments are located on the case front of the V250-S. Refer to Figure B.1 and corre­sponding explanations.
FIGURE B.1 — CASE FRONT CONTROLS.
4
SMAW
SOFT
GTAW
SMAW CRISP
THERMAL
2
A
OUTPUT
3
REMOTE
LOCAL
50
15
120
85
1
INVERTEC V250-S
-
+
250
170
230
8
HOT START
5
6
4
0
ARC FORCE
5
4
0
I
7
8
9
10
6
7
8
9
10
5
6
S
3
2
1
3
2
1
®
1
O
7
1. Power Switch - Place the lever in the “ON” position to energize the machine. When the power is on, the fan will operate and the output will be energized in SMAW modes. GTAW mode requires remote trig­ger to energize the output.
2. Output Control - This controls the output current. Control is provided over the entire output range of the power source with 1 turn of the control knob. This control may be adjusted while under load to change power source output. When using remote control this function becomes the limit setting.
3. Local/Remote Switch - Place in the “LOCAL” posi­tion to allow output adjustment at the machine. Place in the “REMOTE” position to allow output adjustment at remote pot or amptrol. In Remote, the machine output control pot is the limit setting for remote control.
4. Mode Switch
GTAW
Optimized for touch start use. Triggering at amphenol is required using an Arc Start Switch, Amptrol or similar means. Short circuit current is limited to approximately 25 amps to aid in touch starting.
CC Soft
Best for EXX18 thru EXX28 stick elec-
trodes. Output energized when machine is on.
CC Crisp
Use this mode for stick welding with EXX10 thru EXX14 electrodes. Output energized when machine is on.
5. Hot Start - Controls the amount of starting energy in SMAW.
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INVERTEC V250-S
Page 16
B-4
OPERATION
B-4
6. Arc Force - This control functions in SMAW modes
to adjust the Arc Force. The arc is soft at the mini­mum settings and more forceful or driving at the maximum settings. Higher spatter levels may be present at the maximum settings.
RECOMMENDED ARC FORCE/INDUCTANCE SETTINGS FOR SELECTED APPLICATIONS
FULL RANGE IS 1-10. 1 is VERY SOFT,
10 IS VERY CRISP
Nominal Recommended
Mode Process Setting Adjustment Range
CC SMAW 1 EXX18 thru 5 1 (gentle, may stick) to 9
(soft) EXX28 stick (forceful, more spatter)
CC SMAW 2 EXX10 thru 6 3 to 10
(crisp) EXX14 stick
Air Carbon Arc 1 None
Cutting
7. Output Terminals - These quick disconnect termi­nals provide connection points for the electrode and work cables. Refer to Installation chapter for proper cable sizes. For positive polarity welding connect the electrode cable to the positive terminal and the work cable to the negative terminal. To weld negative polarity reverse the electrode and work cables.
Output Connections
in the
CONSTANT CURRENT PROCESSES
MANUAL ARC WELDING (STICK)
The Invertec may be utilized as a manual DC arc welder with the electrode cable, work cable, and elec­trode holder being the only equipment required.
AIR CARBON ARC CUTTING
Air carbon arc cutting may be performed with the Invertec within its output rating using 5/32" (3.9mm) and 3/16" (4.7mm) diameter carbon rods. Output cables, an air carbon arc electrode cable assembly, and a source of compressed air are required.
NOTE:
1. Best performance will be at settings of 200 amps and below.
2. The electronic protection circuit in the V250S will limit the current to approximately 290 amps.
TIG WELDING
The V250S is capable of touch start TIG welding. An electrode cable, work cable, Arc Start Switch or Amptrol, TIG torch, and gas supply with regulator are required. Refer to
Touch starting is done as follows:
Accessories
section of this manual.
8. Thermal Shutdown Indicator - This light will illumi­nate if an internal thermostat has been activated. Machine output will return after the internal components have returned to a normal operating temperature. See chapter.
Thermal Protection
later in this
1. Place the shield cup edge on the work piece.
2. Rock the tungsten down to touch.
3. Trigger the output.
4. Gently rock back the tungsten from the work­piece.
Note: The short circuit current is limited to 25 amps to
aid in touch starting. Panel output control becomes the current limit setting when in remote control
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INVERTEC V250-S
Page 17
B-5
OPERATION
PARALLEL OPERATION
The Invertec’s are operable in parallel. For best results, the currents of each machine should be rea­sonably well shared. As an example, with two machines set up in parallel for a 300 amp procedure, each machine should be set to deliver approximately 150 amps, not 200 amps from one and 100 amps from the other. This will minimize nuisance feedback conditions. In general, more than two machines in par­allel will not be effective due to the voltage require­ments of procedures in that power range.
To set machine outputs, start with output control pots and arc force pots in identical positions. Adjust out­puts and arc forces to maintain current sharing while establishing the proper output current.
OVERLOAD PROTECTION
The machine is electrically protected from producing high output currents. Should the output current exceed 290A, an electronic protection circuit will reduce the current to less than 200A. The machine will continue to produce this low current until the pro­tection circuit is reset. Reset occurs when the output load is removed.
B-5
THERMAL PROTECTION
Thermostats protect the machine from excessive operating temperatures. Excessive temperatures may be caused by a lack of cooling air or operating the machine beyond the duty cycle and output rating. If excessive operating temperature should occur, the thermostats will prevent output voltage or current.
Thermostats are self-resetting once the machine cools sufficiently. If the thermostat shutdown was caused by excessive output or duty cycle and the fan is operating normally, the Power Switch may be left on and the reset should occur within a 15 minute period. If the fan is not turning or the air intake louvers were obstructed, then the power must be switched off for 15 minutes in order to reset. The fan problem or air obstruction must also be corrected.
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INVERTEC V250-S
Page 18
B-6
NOTES
B-6
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INVERTEC V250-S
Page 19
SECTION C-1
OPTIONS / ACCESSORIES........................................................................................................C-2
CABLE PLUGS......................................................................................................................C-2
REMOTE CONTROLS ..........................................................................................................C-2
ACCESSORIES
SECTION C-1
TABLE OF CONTENTS
-ACCESSORIES SECTION-
K852-70 .......................................................................................................................C-2
K852-95 .......................................................................................................................C-2
K857.............................................................................................................................C-2
K963 ............................................................................................................................C-2
K870.............................................................................................................................C-2
K814 ............................................................................................................................C-2
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INVERTEC V250-S
Page 20
C-2
ACCESSORIES
OPTIONS / ACCESSORIES
CABLE PLUGS
K852-70 - Cable Plug Kit for 1/0-2/0 cable. Attaches
to welding cable to provide quick disconnect from machine.
K852-95 - Cable Plug Kit for 2.0-3/0 cable.
NOTE: Two K852-70 plugs are included with the V250-S.
REMOTE CONTROLS
K857 - Remote Output Control for stick welding. K963 - Hand Amptroltmfor TIG welding. When the
V250-S’s Output Control is in the “Remote” position, the hand Amptrol energizes the output and controls the output remotely. The Hand Amptrol connects directly to the 6 pin Amphenol.
C-2
K870 - Foot Amptroltmfor TIG welding. When the
V250-S’s Output Control is in the “REMOTE” position, the foot Amptrol energizes the output and controls the output remotely. The Hand Amptrol connects directly to the 6 pin Amphenol.
K814 - Arc Start Switch. Energizes the output for TIG welding if remote output control of the amperage is not desired. When using the Arc Start Switch set the Output Control to the “LOCAL” position.
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INVERTEC V250-S
Page 21
SECTION D-1
INPUT FILTER CAPACITOR DISCHARGE PROCEDURE.........................................................D-2
ROUTINE MAINTENANCE..........................................................................................................D-3
FILTER CAPACITOR CONDITIONING ......................................................................................D-3
LOCATION OF MAINTENANCE COMPONENTS.......................................................................D-4
MAINTENANCE
TABLE OF CONTENTS
-MAINTENANCE SECTION-
SECTION D-1
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INVERTEC V250-S
Page 22
D-2
MAINTENANCE
D-2
WARNING
ELECTRIC SHOCK can kill.
• Have an electrician install and service this equipment.
• Turn the input power off at the fuse box before working on equipment.
• Do not touch electrically hot parts.
• Prior to Performing preventative main­tenance, perform the following capaci­tor discharge procedure to avoid elec­tric shock.
---------------------------------------------------------------------
INPUT FILTER CAPACITOR DISCHARGE PROCEDURE
1. Turn off input power or disconnect input power lines.
2. Remove the 5/16" hex head screws from the side and top of the machine and remove wrap-around machine cover.
3. Be careful not to make contact with the capacitor terminals that are located in the top and bottom of the Power Board.
4. Obtain a high resistance and high wattage resistor (25-1000 ohms and 25 watts minimum). This resis­tor is not supplied with machine. NEVER USE A SHORTING STRAP FOR THIS PROCEDURE.
5. Locate the four capacitor terminals (large hex head cap screws) shown in Figure D.1. One pair at the top and one pair at the bottom of the Power Board.
6. Use electrically insulated gloves and insulated pli­ers. Hold body of the resistor and connect resistor leads across the two capacitor terminals. Hold resistor in place for 10 seconds. DO NOT TOUCH CAPACITOR TERMINALS WITH YOUR BARE HANDS.
7. Repeat discharge procedure for the capacitor on
other two terminals.
8. Check voltage across terminals of all capacitors with a DC voltmeter. Polarity of capacitor terminals is marked on PC board above terminals. Voltage should be zero. If any voltage remains, repeat this capacitor discharge procedure.
FIGURE D.1 — LOCATION OF INPUT FILTER CAPACITOR TERMINALS.
POWER
BOARD
RIGHT SIDE OF MACHINE
CAP ACIT OR TERMINALS
UPPER 
LOWER  CAPACITOR  TERMINALS
POWER
RESISTOR
INSULATED
PLIERS
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INSULATED
GLOVES
INVERTEC V250-S
Page 23
D-3
MAINTENANCE
D-3
ROUTINE MAINTENANCE
1. Perform the following preventive maintenance procedures at least once every six months. It is good practice to keep a preventive maintenance record; a record tag attached to the machine works best.
2. Remove the machine wrap-around cover and per­form the input filter capacitor discharge procedure (detail at the beginning of this chapter).
3. Keeping the machine clean will result in cooler operation and higher reliability. Be sure to clean the following areas with a low pressure air stream. See figure D.2 for component locations.
Power and control printed circuit boards
Power switch
Main transformer
Input rectifier
Heat sink fins
• Input Filter Capacitors
• Output Terminals
FILTER CAPACITOR CONDITIONING
A protection circuit is included to monitor the voltage across filter capacitors C1 and C2. In the event that the capacitor voltage is too high, the protection circuit will prevent output. Nominal trip setting is at 230/460 VAC +15%. Reset occurs about 3% lower (230/460 VAC +12%).
On new installations, the protection circuit may also prevent output providing all these circumstances are met:
1. Machine is connected for 380-415 or 440-460 VAC input.
2. Machine did not have power applied for many months.
3. Machine will not produce output when power is first switched on.
If these circumstances apply, the proper action is to switch the machine on and let it idle for up to 30 min­utes. This is required to condition the filter capacitors after an extended storage time. The protection circuit will automatically reset once the capacitor conditioning and resultant voltage levels are acceptable. It may be necessary to turn the power switch off and back on again after this period.
4. Examine capacitors for leakage or oozing. Replace if needed.
5. Examine the sheet metal case for dents or break-
age. Repair the case as required. Keep the case in good condition to ensure that high voltage parts are protected and correct spacings are maintained. All external sheet metal screws must be in place to assure case strength and electrical ground continuity.
6. Check electrical ground continuity. Using an ohm­meter, measure resistance between either output terminal and an unpainted surface of the machine case. (See Figure D.2 for locations.) Meter reading should be 500,000 ohms or more. If meter reading is less than 500,000 ohms, check for electrical components that are not properly insulated from the case. Correct insulation if needed.
7. Replace machine cover and screws.
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INVERTEC V250-S
Page 24
D-4
MAINTENANCE
FIGURE D.2 — LOCATION OF MAINTENANCE COMPONENTS.
D-4
CONTROL PC BOARD
POWER SWITCH
OUTPUT TERMINALS
OUTPUT RECTIFIER HEATSINK FINS
INPUT RECTIFIER
POWER PC BOARD
COOLING FANS
MAIN TRANSFORMER
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AUXILIARY TRANSFORMER
INVERTEC V250-S
Page 25
E-1
THEORY OF OPERATION
TABLE OF CONTENTS
-THEORY OF OPERATION SECTION-
GENERAL DESCRIPTION...........................................................................................................E-2
INPUT LINE VOLTAGE................................................................................................................E-2
PRE-CHARGE AND PROTECTION............................................................................................E-3
MAIN TRANSFORMER................................................................................................................E-4
OUTPUT RECTIFICATION AND CONTROL...............................................................................E-5
PROTECTION CIRCUITS............................................................................................................E-6
INSULATED GATE BIPOLAR TRANSISTOR (IGBT) OPERATION............................................E-7
PULSE WIDTH MODULATION (PWM)........................................................................................E-8
E-1
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INVERTEC V250-S
Page 26
E-2
THEORY OF OPERATION
E-2
GENERAL DESCRIPTION
The Invertec V250-S is a 250 amp arc welding power source that utilizes either single or three phase input power to produce a constant current output. The output response of this machine has been optimized for the SMAW and TIG welding processes.
FIGURE E.1 - INPUT VOLTAGE CIRCUITS
INPUT
LINE
SWITCH
FAN
MOTORS
INPUT
RECTIFIER
A"
"
L E A D
AUXILIARY
TRANSFORMER
R E C O N N E C T
S W
I
T C H
18VAC
POWER BOARD
CR1
RELAY
IGBT
CAPACITOR
IGBT
IGBT
CAPACITOR
IGBT
O V E R V O L T A G E
PROTECTION SIGNAL
CR1 RELAY DRIVE SIGNAL
CURRENT TRANSFORMER
GATE SIGNALS
IGBT
REMOTE
RECEPTACLE
MAIN
TRANSFORMER
CONTROL BOARD
OUTPUT
CONTROL
THERMOSTATS
STRIKE
CONTROL
SHUNT
ARC
FORCE
CONTROL
F E E D B A C K
MODE
SWITCH
F E E D B A C K
LOCAL/
REMOTE
SWITCH
POSITIVE
OUTPUT
TERMINAL
NEGATIVE
OUTPUT
TERMINAL
THERMAL
LIGHT
INPUT LINE VOLTAGE
The single-phase or three-phase input power of 208, 230 or 460 volts AC is connected to the machine, through a line switch located on the front panel.
A reconnect panel and switch allows the user to con­figure the machine for either a low or high input volt­age and also connect the auxiliary transformer for the appropriate input voltage.
The auxiliary transformer develops the appropriate AC voltages to operate the cooling fans and the control board.
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NOTE: Unshaded areas of block logic diagrams are the subject of discussion.
INVERTEC V250-S
Page 27
E-3
THEORY OF OPERATION
FIGURE E.2 PROTECTION AND PRE-CHARGE CIRCUITS
E-3
INPUT
LINE
SWITCH
FAN
MOTORS
INPUT
RECTIFIER
A"
"
L E A D
AUXILIARY
TRANSFORMER
R E C O N N E C T
S W
I
T C H
18VAC
POWER BOARD
CR1
RELAY
IGBT
CAPACITOR
IGBT
IGBT
CAPACITOR
IGBT
O V E R V O L T A G E
PROTECTION SIGNAL
CR1 RELAY DRIVE SIGNAL
CURRENT TRANSFORMER
GATE SIGNALS
IGBT
REMOTE
RECEPTACLE
MAIN
TRANSFORMER
CONTROL BOARD
OUTPUT
CONTROL
THERMOSTATS
STRIKE
CONTROL
SHUNT
ARC
FORCE
CONTROL
F E E D B A C K
MODE
SWITCH
F E E D B A C K
LOCAL/
REMOTE
SWITCH
POSITIVE
OUTPUT
TERMINAL
NEGATIVE
OUTPUT
TERMINAL
THERMAL
LIGHT
PRECHARGE AND PROTECTION
The input voltage is rectified and the DC voltage is applied, through the reconnect switch, to the power board. The power board contains precharging circuit­ry for the safe charging of the input filter capacitors. Once the capacitors are precharged and balanced the control board activates the CR1 input relay which con­nects full input power to the filter capacitors. When the filter capacitors are fully charged they act as power supplies for the IGBT switching circuit. The Insulated Gate Bipolar Transistors supply the main transformer primary windings with DC current flow. See
IGBT Operation Discussion and diagrams
this section. The power board also monitors the filter capacitors for voltage balance and/or overvoltage and, if either should occur, sends the appropriate signal to the con­trol board to deactivate the CR1 input relay. The machine output will also be disabled.
in
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NOTE: Unshaded areas of block logic diagrams are the subject of discussion.
INVERTEC V250-S
Page 28
E-4
THEORY OF OPERATION
FIGURE E.3 MAIN TRANSFORMER
E-4
INPUT
LINE
SWITCH
FAN
MOTORS
INPUT
RECTIFIER
A"
"
L E A D
AUXILIARY
TRANSFORMER
R E C O N N E C T
S W
I
T C H
18VAC
POWER BOARD
CR1
RELAY
IGBT
CAPACITOR
IGBT
IGBT
CAPACITOR
IGBT
O V E R V O L T A G E
PROTECTION SIGNAL
CR1 RELAY DRIVE SIGNAL
CURRENT TRANSFORMER
GATE SIGNALS
IGBT
REMOTE
RECEPTACLE
MAIN
TRANSFORMER
CONTROL BOARD
OUTPUT
CONTROL
THERMOSTATS
STRIKE
CONTROL
SHUNT
ARC
FORCE
CONTROL
F E E D B A C K
MODE
SWITCH
F E E D B A C K
LOCAL/
REMOTE
SWITCH
POSITIVE
OUTPUT
TERMINAL
NEGATIVE
OUTPUT
TERMINAL
THERMAL
LIGHT
MAIN TRANSFORMER
Each IGBT pair acts as a switch assembly. Each assembly feeds a separate, oppositely wound primary winding of the main transformer. The reverse direc­tions of current flow through the main transformer pri­maries and the offset timing of the IGBT pairs induce an AC square wave output signal at the secondary of the main transformer. The DC current flow through each primary winding is redirected or “clamped” back to each respective filter capacitor when the IGBTs are turned off. This is needed due to the inductance of the transformer pri­mary winding. The primary currents also pass through the current transformer which sends a signal to the control board. If the primary currents are not equal the control board compensates by adjusting the IGBT gate signals. The firing of both IGBT pairs occurs during halves of the 50 microsecond intervals, creating a constant 20 KHZ output.
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NOTE: Unshaded areas of block logic diagrams are the subject of discussion.
INVERTEC V250-S
Page 29
E-5
THEORY OF OPERATION
FIGURE E.4 OUTPUT RECTIFICATION AND CONTROL
E-5
INPUT
LINE
SWITCH
FAN
MOTORS
INPUT
RECTIFIER
A"
"
L E A D
AUXILIARY
TRANSFORMER
R E C O N N E C T
S W
I
T C H
18VAC
POWER BOARD
CR1
RELAY
IGBT
CAPACITOR
IGBT
IGBT
CAPACITOR
IGBT
O V E R V O L T A G E
PROTECTION SIGNAL
CR1 RELAY DRIVE SIGNAL
CURRENT TRANSFORMER
GATE SIGNALS
IGBT
REMOTE
RECEPTACLE
MAIN
TRANSFORMER
CONTROL BOARD
OUTPUT
CONTROL
THERMOSTATS
STRIKE
CONTROL
SHUNT
ARC
FORCE
CONTROL
F E E D B A C K
MODE
SWITCH
F E E D B A C K
LOCAL/
REMOTE
SWITCH
POSITIVE
OUTPUT
TERMINAL
NEGATIVE
OUTPUT
TERMINAL
THERMAL
LIGHT
OUTPUT RECTIFICATION AND CONTROL
The AC output from the main transformer secondary is rectified to a DC output and applied to the output terminals. Output voltage and current feedback infor­mation, which is fed to the control board, is sensed at the output terminals and shunt. The control board monitors the panel controls and remote control recep­tacle and compares these commands to the feedback information to determine how the output should be controlled to optimized welding results. The control board controls the IGBT switching through pulse width modulation circuitry. See in this section.
IGBT Operation
Discussion
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NOTE: Unshaded areas of block logic diagrams are the subject of discussion.
INVERTEC V250-S
Page 30
E-6
THEORY OF OPERATION
PROTECTION CIRCUITS
Protective circuits are designed into the V250-S machine to sense trouble and shut down the machine before the trouble damages the internal machine com­ponents. Both overload and thermal protection cir­cuits are included.
E-6
OVERLOAD PROTECTION
The V250-S is electrically protected from producing high output currents. Should the output current exceed 290 amps, an electronic protection circuit will reduce the current to less than 200 amps. Lincoln Electric refers to this current reduction as “Fold Back”. The machine will continue to produce this low current until the protection circuit is reset. Reset occurs when the output load is removed.
A protection circuit is included to monitor the voltage across the input filter capacitors. In the event that the capacitor voltage is too high, the protection circuit will prevent output. On new installations, the protection circuit may pre­vent output, due to unbalanced capacitor leakages, providing the following circumstances are met:
1. Machine is connected for 380 - 460VAC input.
2. Machine did not have power applied for many months.
3. Improper connections.
THERMAL PROTECTION
Thermostats protect the machine from excessive operating temperatures. Excessive temperatures may be caused by a lack of cooling air or operating the machine beyond the duty cycle and output rating. If excessive operating temperature should occur, the thermostat will prevent output voltage or current and the thermal indicator light will glow.
Thermostats are self-resetting once the machine cools sufficiently. If the thermostat shutdown was caused be excessive output or duty cycle and the fan is oper­ating normally, the power switch may be left on and the reset should occur within 15 minute period. If the fan is not turning or the air intake louvers were obstructed, then the power must be switched off for 15 minutes in order to reset. The fan problem or air obstruction must be corrected.
4. Internal component damage.
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NOTE: Unshaded areas of block logic diagrams are the subject of discussion.
INVERTEC V250-S
Page 31
E-7
THEORY OF OPERATION
INSULATED GATE BIPOLAR TRANSISTOR (IGBT) OPERATION
E-7
An IGBT is a type of transistor. IGBTs are semicon­ductors well suited for high frequency switching and high current applications.
Drawing A shows an IGBT in a passive mode. There is no gate signal, zero volts relative to the source, and therefore, no current flow. The drain terminal of the IGBT may be connected to a voltage supply; but since there is no conduction the circuit will not supply cur­rent to components connected to the source. The cir­cuit is turned off like a light switch in the OFF position.
Drawing B shows the IGBT in an active mode. When the gate signal, a positive DC voltage relative to the
FIGURE E.6 IGBT OPERATION
source, is applied to the gate terminal of the IGBT, it is capable of conducting current. A voltage supply connected to the drain terminal will allow the IGBT to conduct and supply current to circuit components coupled to the source. Current will flow through the conducting IGBT to downstream components as long as the positive gate signal is present. This is similar to turning ON a light switch.
SOURCE
n + n +
p
n -
n + p +
DRAIN
A. PASSIVE
GATE
BODY REGION
DRAIN DRIFT REGION
BUFFER LAYER
INJECTING LAYER
SOURCE
n + n +
p
n -
n + p +
DRAIN
B. ACTIVE
POSITIVE  VOLTAGE APPLIED
GATE
BODY REGION
DRAIN DRIFT REGION
BUFFER LAYER
INJECTING LAYER
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INVERTEC V250-S
Page 32
E-8
THEORY OF OPERATION
PULSE WIDTH MODULATION
E-8
The term PULSE WIDTH MODULATION is used to describe how much time is devoted to conduction in the positive and negative portions of the cycle. Changing the pulse width is known as MODULATION. Pulse Width Modulation (PWM) is the varying of the pulse width over the allowed range of a cycle to affect the output of the machine.
MINIMUM OUTPUT
By controlling the duration of the gate signal, the IGBT is turned on and off for different durations during a cycle. The top drawing below shows the minimum output signal possible over a 50-microsecond time period.
1
An IGBT group consists of two IGBT modules feeding one transformer primary winding.
The positive portion of the signal represents one IGBT group1conducting for 1 microsecond. The negative portion is the other IGBT group1. The dwell time (off time) is 48 microseconds (both IGBT groups off). Since only 2 microseconds of the 50-microsecond time period is devoted to conducting, the output power is minimized.
MAXIMUM OUTPUT
By holding the gate signals on for 24 microseconds each and allowing only 2 microseconds of dwell time (off time) during the 50-microsecond cycle, the output is maximized. The darkened area under the top curve can be compared to the area under the bottom curve. The more dark area under the curve, the more power is present.
sec
FIGURE E.7 TYPICAL IGBT OUTPUTS
sec
48
sec
50
MINIMUM OUTPUT
sec
24
sec
2
sec
50
sec
24
sec
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MAXIMUM OUTPUT
INVERTEC V250-S
Page 33
SECTION F-1
TROUBLESHOOTING & REPAIR
SECTION F-1
TABLE OF CONTENTS
-TROUBLESHOOTING & REPAIR SECTION-
TROUBLESHOOTING AND REPAIR SECTION.........................................................................SECTION F
HOW TO USE TROUBLESHOOTING GUIDE.............................................................................F-2
PC BOARD TROUBLESHOOTING PROCEDURES...................................................................F-3
TROUBLESHOOTING GUIDE.....................................................................................................F-4
TEST PROCEDURES
AUXILIARY TRANSFORMER TEST ...................................................................................F-11
INPUT RECTIFIER TEST....................................................................................................F-15
POWER BOARD RESISTANCE TEST................................................................................F-19
OUTPUT DIODE TEST........................................................................................................F-23
POWER BOARD VOLTAGE TEST......................................................................................F-27
CONTROL BOARD VOLTAGE TEST..................................................................................F-31
PROTECTION CIRCUIT TEST............................................................................................F-35
CAPACITOR BALANCE TEST............................................................................................F-39
REPAIR AND REPLACEMENT PROCEDURES
CONTROL BOARD REMOVAL AND REPLACEMENT.......................................................F-43
POWER BOARD REMOVAL AND REPLACEMENT...........................................................F-45
FILTER CAPACITOR REMOVAL AND REPLACEMENT....................................................F-49
INPUT RECTIFIER BRIDGE REMOVAL AND REPLACEMENT ........................................F-53
OUTPUT DIODE ASSEMBLY REMOVAL AND REPLACEMENT ......................................F-57
(MACHINE CODES BELOW 10150)
OUTPUT DIODE ASSEMBLY REMOVAL AND REPLACEMENT ......................................F-61
(MACHINE CODES ABOVE 10150)
MAIN TRANSFORMER REMOVAL AND REPLACEMENT................................................F-65
(MACHINE CODES BELOW 10150)
MAIN TRANSFORMER REMOVAL AND REPLACEMENT................................................F-71
(MACHINE CODES ABOVE 10150)
RETEST AFTER REPAIR..........................................................................................................F-77
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INVERTEC V250-S
Page 34
F-2
TROUBLESHOOTING & REPAIR
F-2
HOW TO USE TROUBLESHOOTING GUIDE
WARNING
Service and Repair should only be performed by Lincoln Electric Factory Trained Personnel. Unauthorized repairs performed on this equipment may result in danger to the technician and machine operator and will invalidate your factory warranty. For your safety and to avoid Electrical Shock, please observe all safety notes and precautions detailed throughout this manual.
__________________________________________________________________________
This Troubleshooting Guide is provided to help you locate and repair possible machine malfunctions. Simply follow the three-step procedure listed below.
Step 1. LOCATE PROBLEM (SYMPTOM).
Look under the column labeled “PROBLEM (SYMPTOMS)”. This column describes possible symptoms that the machine may exhibit. Find the listing that best describes the symptom that the machine is exhibiting. Symptoms are grouped into the following categories: output problems and welding problems.
Step 2. PERFORM EXTERNAL TESTS.
The second column labeled “POSSIBLE AREAS OF MISADJUSTMENT(S)” lists the obvious external possibilities that may con­tribute to the machine symptom. Perform these tests/checks in the order listed. In general, these tests can be conducted with­out removing the case wrap-around cover.
Step 3. RECOMMENDED COURSE OF ACTION
The last column labeled “Recommended Course of Action” lists the most likely com­ponents that may have failed in your machine. It also specifies the appropriate test procedure to verify that the subject component is either good or bad. If there are a number of possible components, check the components in the order listed to eliminate one possibility at a time until you locate the cause of your problem.
All of the referenced test procedures referred to in the Troubleshooting Guide are described in detail at the end of this chap­ter. Refer to the Troubleshooting and Repair Table of Contents to locate each specific Test Procedure. All of the specified test points, components, terminal strips, etc. can be found on the referenced electrical wiring diagrams and schematics. Refer to the Electrical Diagrams Section Table of Contents to locate the appropriate diagram.
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CAUTION
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical trou­bleshooting assistance before you proceed call 216-383-2531 or 1-800-833-9353.
_____________________________________________________________
OSCILLOSCOPE WARNING
WARNING
Do not use oscilloscopes and other test equipment which are powered by 115 VAC. This equipment should not be used with inverter-type machines, such as Invertec V250-S. There are high voltages present, which are “floating” off case ground (floating ground). Connecting the ground lead of a test probe (which may be connected to the case of the test equipment) to a high voltage potential presents a shock hazard as well as the possibility of damage to the equipment in question.
_____________________________________________________________________
INVERTEC V250-S
Page 35
F-3
TROUBLESHOOTING & REPAIR
PC BOARD TROUBLESHOOTING PROCEDURES
F-3
WARNING
ELECTRIC SHOCK can kill. Have an electrician install and service this equip­ment. Turn the input power OFF at the fuse box before working on equipment. Do not touch electrically hot parts.
_______________________________
CAUTION: Sometimes machine failures appear to be due to PC board failures. These problems can sometimes be traced to poor electrical connections. To avoid problems when troubleshooting and replacing PC boards, please use the following procedure:
1. Determine to the best of your technical ability that the PC board is the most likely component causing the failure symptom.
2. Check for loose connections at the PC board to assure that the PC board is prop­erly connected.
3. If the problem persists, replace the sus­pect PC board using standard practices to avoid static electrical damage and electri­cal shock. Read the warning inside the static resistant bag and perform the follow­ing procedures:
- Remove the P.C. Board from the static­shielding bag and place it directly into the equipment. Don’t set the P.C. Board on or near paper, plastic or cloth which could have a static charge. If the P.C. Board can’t be installed immediately, put it back in the static­shielding bag.
- If the P.C. Board uses protective shorting jumpers, don’t remove them until installation is complete.
- If you return a P.C. Board to The Lincoln Electric Company for credit, it must be in the static-shielding bag. This will prevent further damage and allow proper failure analysis.
4. Test the machine to determine if the fail­ure symptom has been corrected by the replacement PC board.
NOTE: It is desirable to have a spare (known good) PC board available for PC board trou­bleshooting.
NOTE: Allow the machine to heat up so that all electrical components can reach their oper­ating temperature.
5. Remove the replacement PC board and substitute it with the original PC board to recreate the original problem.
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P.C. Board can be dam­aged by static electricity.
- Remove your body’s stat­ic charge before opening
ATTENTION Static-Sensitive Devices Handle only at Static-Safe Workstations
Reusable Container Do Not Destroy
equipment frame. Keep touching the frame to prevent static build-up. Be sure not to touch any electrically live parts at the same time.
- Tools which come in contact with the P.C. Board must be either conductive, anti-static or static-dissipative.
the static-shielding bag. Wear an anti-static wrist strap. For safety, use a 1 Meg ohm resistive cord connected to a grounded part of the equipment frame.
- If you don’t have a wrist strap, touch an unpainted, grounded, part of the
INVERTEC V250-S
a. If the original problem does not reap-
pear by substituting the original board, then the PC board was not the problem. Continue to look for bad connections in the control wiring har­ness, junction blocks, and terminal strips.
b. If the original problem is recreated by
the substitution of the original board, then the PC board was the problem. Reinstall the replacement PC board and test the machine.
6. Always indicate that this procedure was followed when warranty reports are to be submitted.
NOTE: Following this procedure and writing on the warranty report, “INSTALLED AND SWITCHED PC BOARDS TO VERIFY PROBLEM,” will help avoid denial of legitimate PC board warranty claims.
Page 36
F-4
TROUBLESHOOTING & REPAIR
Observe all Safety Guidelines detailed throughout this manual
F-4
PROBLEMS
(SYMPTOMS)

Major physical or electrical damage is observed when cover wrap-around is removed.

The machine is dead - no output ­no fan.
POSSIBLE AREAS OF
MISADJUSTMENT(S)
OUTPUT PROBLEMS
Contact your local Lincoln Authorized Field Service Facility.
1. The input power switch must be in the ON position.
2. Make sure the input voltage is correct for the machine.
3. If the machine is set for single­phase operation, inspect to assure that the WHITE and BLACK leads are connected properly and the RED lead is not connected and is insulated.
4. Check that the input voltage set­up switch and jumper “A” (the reconnect auxiliary jumper) are in the proper position for the input voltage being applied. Refer to
Input Voltage Reconnect Procedure
Chapter.
in the Installation
RECOMMENDED
COURSE OF ACTION
Contact Lincoln Electric Service Department (216)-383-2531 or 1-800-833-9353
1. The power switch (S1) may be faulty. Check or replace.
2. Check for loose or broken leads between the power switch (S1) and the input rectifier D9. See wiring diagram.
3. Perform the
Transformer Test
Auxiliary
.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353.
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5. Check continuity of the 0.6-amp slow blow fuse located on the reconnect panel.
CAUTION
INVERTEC V250-S
Page 37
F-5
TROUBLESHOOTING & REPAIR
Observe all Safety Guidelines detailed throughout this manual
F-5
PROBLEMS
(SYMPTOMS)
No output but the fan operates nor­mally.
POSSIBLE AREAS OF
MISADJUSTMENT(S)
OUTPUT PROBLEMS
1. The mode switch must be in one of the SMAW modes or if in the GTAW mode the remote trigger circuit must be activated.
2. The Local/Remote switch (S3) must be in the LOCAL position unless a remote control device is attached to the remote receptacle.
3. If the machine has not been used for a long time and is connected for 380 VAC or higher, the capacitors may need “condition­ing”. See
Conditioning
4. The machine may be overheated. Check the thermal indicator light. Wait for the machine to cool and the thermostats to reset.
Input Filter Capacitor
.
RECOMMENDED
COURSE OF ACTION
1. Perform the
Transformer Test
2. Check for loose or broken connections on the high current carrying parts of the V250-S. (i.e., output diodes, output terminals, shunt and main transformer connections.)
3. Check the continuity of the normally closed thermostats and associated wiring. See wiring diagram.
4. Perform the
5. Perform the
Test
.
6. Perform the
Test
.
Auxiliary
.
Output Diode Test Capacitor Balance
Protection Circuit
.
CAUTION
7. Perform the
Voltage Checks
8. Perform the
Voltage Checks
Power Board
.
Control Board
.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353.
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INVERTEC V250-S
Page 38
F-6
TROUBLESHOOTING & REPAIR
Observe all Safety Guidelines detailed throughout this manual
F-6
PROBLEMS
(SYMPTOMS)

Output turns on momentarily, then switches off and repeats cycle.

POSSIBLE AREAS OF
MISADJUSTMENT(S)
OUTPUT PROBLEMS
1. Check the input voltages and reconnection procedures. Make sure the input voltage is correct for the machine. See
Voltage Reconnect Procedure
2. Check or replace remote control device. (If used)
Input
RECOMMENDED
COURSE OF ACTION
1. Check Local/Remote switch (S3) and associated wiring for loose or faulty connections.
.
2. Check Mode Switch (S2) and associated wiring for loose or faulty connections.
3. If the machine is connected for 380VAC input or higher, perform the
Capacitor Balance Test
4. The power board may be faulty. Replace.
5. The control board may be faulty. Replace.
.

Remote output control not functioning. The machine operates normally on LOCAL control.

1. Make sure the Local/Remote switch (S3) is in the REMOTE position.
2. The remote control device may be faulty. Replace.
1. Check the Local/Remote switch (S3) and the associated wiring. See wiring diagram.
2. Check for loose or faulty connections at the remote control receptacle.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353.
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CAUTION
INVERTEC V250-S
Page 39
F-7
TROUBLESHOOTING & REPAIR
Observe all Safety Guidelines detailed throughout this manual
F-7
PROBLEMS
(SYMPTOMS)

No output - Main input fuses open, indicating excessive current draw.

The machine operates normally when connected for 200 - 230VAC input. There is no output when the machine is connected to 380VAC or higher.
POSSIBLE AREAS OF
MISADJUSTMENT(S)
OUTPUT PROBLEMS
1. Inspect input leads for possible shorts or grounds or mis-connec­tions.
2. Install new fuses and reapply power. If fuses open again, con­sult a Lincoln Authorized Field Service Facility.
1. Check the input voltage and input voltage reconnect procedures. See
Installation Section
manual.
of this
RECOMMENDED
COURSE OF ACTION
1. Inspect interior of machine for physical signs of electrical and heat damage. Replace any dam­aged components after conduct­ing the following tests.
2. Perform the
3. Perform
Resistance Test
4. Check the reconnect switch and associated leads for “shorts” or faulty wiring.
1. Perform the
Test
.
2. Perform the
Test
.
Input Rectifier Test
Power Board
.
Capacitor Balance
Protection Circuit
.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353.
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CAUTION
INVERTEC V250-S
3. Perform the
Transformer Test
4. Perform the
Resistance Test
Auxiliary
.
Power Board
.
Page 40
F-8
TROUBLESHOOTING & REPAIR
Observe all Safety Guidelines detailed throughout this manual
F-8
PROBLEMS
(SYMPTOMS)

The machine will not produce more than 200 amps.

POSSIBLE AREAS OF
MISADJUSTMENT(S)
OUTPUT PROBLEMS
1. This may be normal operation. If the output current exceeds 290 amps, an electronic protection circuit will reduce the current to less than 200 amps. The machine will continue to produce this low current until the protection circuit is reset. Reset occurs when the output load is removed.
2. Check the input voltage and input voltage reconnect procedures. See
Input Voltage Reconnect
Procedure
3. Check for loose or faulty welding cables.
.
RECOMMENDED
COURSE OF ACTION
1. Perform the
2. The control board may be faulty. Replace.
Output Diode Test
.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353.
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CAUTION
INVERTEC V250-S
Page 41
F-9
TROUBLESHOOTING & REPAIR
Observe all Safety Guidelines detailed throughout this manual
F-9
PROBLEMS
(SYMPTOMS)

Poor welding, weld settings drift, or output power is low.

Poor stick electrode welding performance. The arc pops out.

POSSIBLE AREAS OF
MISADJUSTMENT(S)
WELDING PROBLEMS
1. Make sure the machine settings are correct for the weld process being used.
2. Check machine performance on LOCAL control. If OK then the remote control device may be faulty. Check or replace.
3. Check the input voltages and input voltage reconnect procedures. See
Section
1. Check for loose or faulty welding cables.
2. Is the electrode DRY? Try weld­ing with another electrode from a different container. Make sure you have the correct electrode for the application.
of this manual.
Installation
RECOMMENDED
COURSE OF ACTION
1. Check the operation of the mode switch (S2) and the associated circuitry. See wiring diagram.
2. Check for loose or faulty connec­tions in the heavy current carrying leads (i,e,. output diodes, output terminals, shunt and main trans­former.)
3. Perform
4. Perform
Test
1. Check for loose or faulty connec­tions in the heavy current carrying leads (i,e,. output diodes, output terminals, shunt and main trans­former.)
2. Perform
Output Diode Test Control Board Voltage
.
Output Diode Test
.
.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353.
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3. Make sure the machine settings are correct for the weld process being used.
CAUTION
INVERTEC V250-S
3. Perform
Test
.
Control Board Voltage
Page 42
F-10
NOTES
F-10
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INVERTEC V250-S
Page 43
F-11
TROUBLESHOOTING & REPAIR
AUXILIARY TRANSFORMER TEST
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-11
TEST DESCRIPTION
This test will determine if the auxiliary transformer is functional when the correct primary volt­age is applied to the primary winding.
MATERIALS NEEDED
Volt/ohmmeter Machine wiring diagram 5/16” nut-driver 230VAC isolated power supply
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INVERTEC V250-S
Page 44
F-12
TROUBLESHOOTING & REPAIR
AUXILIARY TRANSFORMER TEST (continued)
F-12
TEST PROCEDURE
1. Remove main input power to the V250-S.
2. Perform Filter Capacitor Discharge Procedure detailed in Maintenance Section
3. Locate the Auxiliary Transformer just behind the input line switch on the lower right side of the machine.
AUXILIARY TRANSFOMER
PLUG J7
4. Locate and disconnect plug J7 from the wiring harness.
5. Carefully apply the 230VAC isolated supply to leads H1(1J7) and H3(2J7) of the auxiliary transformer.
6. Carefully check for the presence of the following voltages at the appro­priate leads. See
Table F.1
.
1J7
4J7
2J7
5J7
3J7
6J7
Figure F.1 Auxiliary Transformer and Plug J7.
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INVERTEC V250-S
Page 45
F-13
TROUBLESHOOTING & REPAIR
AUXILIARY TRANSFORMER TEST (continued)
TABLE F.1 Auxiliary Transformer Test Points
TEST POINT TEST POINT EXPECTED VOLTAGE
H1 (1J7) H2 (4J7) 200 - 208VAC H1 (1J7) H4 (3J7) 380 - 415VAC H1 (1J7) H5 (6J7) 440 - 460VAC
RED LEAD (1J1) RED LEAD (3J1) 18VAC (SECONDARY)
On Control Board On Control Board
7. If the correct test voltages are pre­sent the auxiliary transformer is good.
8. If any of the voltages are missing or very low, with the proper primary voltage applied, the auxiliary trans­former may be faulty. Replace.
F-13
9. If the auxiliary transformer tests good but does not function when connect­ed to the V250-S check the harness wiring to the auxiliary transformer. See wiring diagram.
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INVERTEC V250-S
Page 46
F-14
NOTES
F-14
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INVERTEC V250-S
Page 47
F-15
TROUBLESHOOTING & REPAIR
INPUT RECTIFIER TEST
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-15
TEST DESCRIPTION
This test will help determine if the input rectifier has “shorted” or “open” diodes.
MATERIALS NEEDED
Analog voltmeter/ohmmeter (Multimeter) Phillips head screwdriver Wiring diagram
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INVERTEC V250-S
Page 48
F-16
TROUBLESHOOTING & REPAIR
INPUT RECTIFIER TEST (continued)
TEST PROCEDURE
F-16
1. Remove main input power to the V250-S.
2. Perform
Procedure
Section.
3. Locate Input Rectifier (D9) and lead locations.
Filter Capacitor Discharge
detailed in Maintenance
4. With the Phillips head screwdriver remove leads #207, 207A and #209 from the rectifier. See Figure F.2.
5. Use the analog ohmmeter to perform the tests detailed in wiring diagram.
Table F.2.
See
#207 #207A
A
B
C
#209
Figure F.2 Input Rectifier and Leads.
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INVERTEC V250-S
Page 49
F-17
TROUBLESHOOTING & REPAIR
INPUT RECTIFIER TEST (continued)
TABLE F.2 Input Rectifier Test Points
TEST POINT TERMINALS ANALOG METER X10 RANGE + Probe - Probe Acceptable Meter Readings
A 207 Greater than 1000 ohms B 207 Greater than 1000 ohms
C 207 Greater than 1000 ohms
A 209 Less than 100 ohms B 209 Less than 100 ohms
C 209 Less than 100 ohms
207 A Less than 100 ohms 207 B Less than 100 ohms 207 C Less than 100 ohms
209 A Greater than 1000 ohms 209 B Greater than 1000 ohms 209 C Greater than 1000 ohms
F-17
6. If the Input Rectifier does not meet the acceptable readings outlined in Table F.2. the component may be faulty. Replace.
Note: Before replacing the Input
Rectifier(D9) check the input power switch (S1) and perform the
Power Board Resistance
Test
. Also check for leaky or
faulty filter capacitors.
7. When installing a new Input
Rectifier, torque the mounting nuts to 44IN-LBS. A thin coating of Dow Corning 340 Heat Sink Compound (Lincoln E1868) is recommended. Torque the lead terminals to 31IN­LBS. See
Removal And Replacement
Input Rectifier Bridge
.
8. If the Input Rectifier is good be sure to reconnect leads #207, #207A and #209 to the correct terminals and torque to 31IN-LBS. See wiring dia­gram and Figure F.2.
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INVERTEC V250-S
Page 50
F-18
NOTES
F-18
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INVERTEC V250-S
Page 51
F-19
TROUBLESHOOTING & REPAIR
POWER BOARD RESISTANCE TEST
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-19
TEST DESCRIPTION
This test will help determine if the Power Board has any “shorted” or “leaky” power diodes or Insulated Gate Bipolar Transistors. Also it will help to indicate any “shorted” filter capacitors.
MATERIALS NEEDED
Analog voltmeter/ohmmeter (Multimeter) Wiring diagram
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INVERTEC V250-S
Page 52
F-20
TROUBLESHOOTING & REPAIR
POWER BOARD RESISTANCE TEST (continued)
TEST DESCRIPTION
F-20
1. Remove main input power to the V250 -S.
2. Perform
Procedure
Section.
3. Locate the Power Board and associ­ated lead locations. See Figure F.3.
Filter Capacitor Discharge
detailed in Maintenance
201
204
4. Carefully remove main transformer primary leads #201, #204, #205 and #208 from the power board.
5. Use the analog ohmmeter to perform the tests outlined in power board schematic.
Table F.3
+
207A
202A
. See
DANGER
HIGH VOLTAGE CAN KILL
V250S POWER G2684
209
208
205
203A
Figure F.3 Power Board Test Points.
+
206
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INVERTEC V250-S
Page 53
F-21
TROUBLESHOOTING & REPAIR
POWER BOARD RESISTANCE TEST (continued)
TABLE F.3 Power Board Resistance Test Points.
TEST POINT TERMINALS ANALOG METER X10 RANGE + Probe - Probe Acceptable Meter Readings
201 207A Greater than 1000 ohms
207A 201 Less than 100 ohms
204 207A Greater than 1000 ohms
207A 204 Less than 100 ohms 202A 204 Greater than 1000 ohms
204 202A Less than 100 ohms
202A 201 Greater than 1000 ohms
201 202A Less than 100 ohms 205 203A Greater than 1000 ohms
203A 205 Less than 100 ohms
F-21
208 203A Greater than 1000 ohms
203A 208 Less than 100 ohms
206 208 Greater than 1000 ohms 208 206 Less than 100 ohms
206 205 Greater than 1000 ohms 205 206 Less than 100 ohms
6. If the power board does not meet the acceptable readings outlined in Table F.3. the board may be faulty. Replace. See
Removal and Replacement Procedure
Note: Complete power board and filter capacitor replacement is recommended .
7. If the power board “passes” the resistance test proceed to the
Board Voltage Test
.
Power Board
Power
.
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Note: Reconnect leads #201, #204, #205 and #208 to their appropriate ter­minals.
INVERTEC V250-S
Page 54
F-22
NOTES
F-22
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INVERTEC V250-S
Page 55
F-23
TROUBLESHOOTING & REPAIR
OUTPUT DIODES TEST
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-23
TEST DESCRIPTION
This test will help determine if any of the output diodes are “shorted”.
MATERIALS NEEDED
Analog voltmeter/ohmmeter (Multimeter) Wiring diagram. Note: Output diode polarity will vary with machine codes.
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INVERTEC V250-S
Page 56
F-24
TROUBLESHOOTING & REPAIR
OUTPUT DIODES TEST (continued)
F-24
TEST PROCEDURE
1. Remove main input power to the V250-S.
2. Locate the output terminals on the front panel of the machine. See Figure F.4.
3. Remove any output cables and load from the output terminals.
SMAW
SOFT
GTAW
SMAW CRISP
A
OUTPUT
50
THERMAL
85
4. Using the analog ohmmeter test for more than 200 ohms resistance between positive and negative out­put terminals. Positive test lead to the positive terminal; Negative test lead to the negative terminal. See Figure F.5.
NOTE: THE POLARITY OF THE TEST LEADS IS MOST IMPORTANT. IF THE TEST LEADS POLARITY IS NOT CORRECT THE TEST WILL HAVE ERRONEOUS RESULTS.
HOT START
5
6
4
7
8
0
9
10
120
3
2
1
170
NEGATIVE OUTPUT  TERMINAL
Figure F.4 Machine Output Terminals.
REMOTE
15
LOCAL
1
INVERTEC V250-S
-
+
250
230
3
2
®
POSITIVE OUTPUT  TERMINAL
ARC FORCE
4
1
0
O
5
6
7
8
9
10
S
I
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INVERTEC V250-S
Page 57
F-25
TROUBLESHOOTING & REPAIR
OUTPUT DIODES TEST (continued)
INVERTEC V250-S
-
- PROBE
+
+ PROBE
F-25
®
S
I
O
Figure F.5 Meter Probes.
5. If more than 200 ohms is measured the output diodes are not “shorted”.
6. If less than 200 ohms is measured, one or more output diodes or snub­bers may be shorted or “leaky”.
7. Perform
Procedure
Section.
Filter Capacitor Discharge
detailed in Maintenance
8. Locate output diodes and snubbers. See Figure F.6. for machine codes 10102 and 10103 only. See Figure F.7. for machine codes 10187 and 10188 only.
9. Test all output diodes and snubbers
(if used) individually.
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INVERTEC V250-S
Page 58
F-26
TROUBLESHOOTING & REPAIR
OUTPUT DIODES TEST (continued)
OUTPUT DIODES
SNUBBERS
F-26
Figure F.6 Output Diodes and Snubber Locations (Codes 10102 and 10103)
DIODE MODULES
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Figure F.7 Output Diode Module Locations (Codes 10187 and 10188)
INVERTEC V250-S
Page 59
F-27
TROUBLESHOOTING & REPAIR
POWER BOARD VOLTAGE TEST
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-27
TEST DESCRIPTION
This test will aid the technician in determining if the voltage board or some other machine component may be faulty.
MATERIALS NEEDED
Voltmeter/ohmmeter (Multimeter) Wiring diagram. Power board schematic drawing.
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INVERTEC V250-S
Page 60
F-28
N
2
+
+
TROUBLESHOOTING & REPAIR
POWER BOARD VOLTAGE TEST (continued)
F-28
TEST PROCEDURE
1. Remove main input power to the V250-S.
2. Perform
Procedure
Filter Capacitor Discharge
detailed in Maintenance
Section.
3. Locate and familiarize yourself with the leads and pin locations in plug J6 on the power board. See Figure F.8.
#309 (6J6)
4. The following tests will be performed with the input power applied to the V250-S. BE CAREFUL. ALWAYS
REMOVE INPUT POWER AND PERFORM FILTER CAPACITOR DISCHARGE PROCEDURE BEFORE TOUCHING ANY MACHINE COMPONENT.
5. Apply input power and turn On the V250-S.
6. Perform the voltage checks outlined in
Table F.4
. making sure all of the
test conditions are in effect.
#313 (5J6)
#311 (4J6)
205
#310 (3J6)
209
208
203A
#307 (2J6)
PLUG J6
J6
V250S POWER G2684
DANGER
HIGH VOLTAGE CA
#308 (1J6)
204
201
207A
20
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Figure F.8 Plug J6 on Power Board
INVERTEC V250-S
Page 61
F-29
POWER BOARD VOLTAGE TEST (continued)
TEST DESCRIPTION
TROUBLESHOOTING & REPAIR
TABLE F.4. Power Board Voltage Test Points.
ACCEPTABLE
TEST POINTS
VOLTAGES
F-29
TEST CONDITIONS
The PWM pulse drive from the control board to the pulse transformer primary located on the power board.
The PWM pulse drive from the control board to the pulse transformer primary located on the power board.
The PWM pulse drive from the control board to the pulse transformer primary located on the power board.
The PWM pulse drive from the control board to the pulse transformer primary located on the power board.
Lead #307 (2J6)
to
Negative output terminal
Lead #308 (1J6)
to
Negative output terminal
Lead #307 (2J6)
to
Negative output terminal
Lead #308 (1J6)
to
Negative output terminal
14VDC.
14VDC.
7VDC.
7VDC.
No load on the machine - the mode switch in SMAW posi­tion.
No load on the machine - the mode switch in SMAW posi­tion.
Machine loaded to 250Amps. The output control R3 at the maximum position.
Machine loaded to 250Amps. The output control R3 at the maximum position.
CR1 (charge relay) coil volt­age.
This low voltage will be pre­sent when the protection cir­cuit has determined that the filter capacitor voltage is acceptable. Note: The CR1 charge relay should be acti­vated.
This voltage will be present unit the protection circuit determines that the filter capacitor is at an acceptable level. Note: The CR1 charge relay will not be activated.
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Lead #309 (6J6)+
to
lead #310 (3J6)
Lead #311 (4J6)+
to
lead #313 (5J6)-
Lead #311 (4J6)+
to
lead #313 (5J6)-
INVERTEC V250-S
12VDC
0 to 1VDC.
15VDC.
This voltage should be pre­sent only after the protection circuit as been satisfied.
If voltage protection circuit IS satisfied.
If voltage protection circuit is NOT satisfied.
Page 62
F-30
NOTES
F-30
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INVERTEC V250-S
Page 63
F-31
TROUBLESHOOTING & REPAIR
CONTROL BOARD VOLTAGE TEST
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-31
TEST DESCRIPTION
This test will aid the technician in determining if the control board or some other machine component may be faulty.
MATERIALS NEEDED
Voltmeter/ohmmeter (Multimeter) Wiring diagram. Control board schematic drawing.
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INVERTEC V250-S
Page 64
F-32
TROUBLESHOOTING & REPAIR
CONTROL BOARD VOLTAGE TEST (continued)
F-32
1J1 
(RED LEAD)
3J1 
(RED LEAD)
TEST PROCEDURE
1. Remove main input power to the V250-S.
2. Perform
Discharge Procedure
Maintenance Section.
3. Locate and familiarize yourself with the leads and pin locations in plugs J1 thru J5 on the control board. See Figure F.9.
J1
Filter Capacitor
detailed in
1J5
(#322)
J2 J5 J3 J4
4J5
(#318)
4. The following tests will be performed with the input power applied to the V250-S. BE CAREFUL. ALWAYS REMOVE INPUT POWER AND PERFORM FILTER CAPACITOR DISCHARGE PROCEDURE BEFORE TOUCHING ANY MACHINE COMPONENT.
5. Apply input power and turn ON the V250 -S.
6. Perform the voltage checks outlined in
Table F.5
. making sure all of the
test conditions are in effect.
1J3
(#375)
7J3
(#303)
(BLACK LEAD)
(WHITE LEAD)
1J4
2J4
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G2666-[ ]
V250S CONTROL
Figure F.9 Plugs J1-J5 on Control Board
INVERTEC V250-S
Page 65
F-33
CONTROL BOARD VOLTAGE TEST (continued)
TEST DESCRIPTION
TROUBLESHOOTING & REPAIR
TABLE F.5. Control Board Voltage Test Points.
ACCEPTABLE
TEST POINTS
VOLTAGES
F-33
TEST CONDITIONS
The 18VAC from the auxil­iary transformer to the con­trol board.
Remote trigger circuit test. (#2 and #4)
Remote trigger circuit test. (#2 and #4)
Shunt feedback milli-volt check.
Red lead (1J1)
to
Red lead (3J1)
Lead #318 (4J5)
to
Lead #322 (1J5)
Lead #318 (4J5)
to
Lead #322 (1J5)
White lead (2J4)+
to
Black lead (1J4)-
18VAC
Note: voltage will vary with
input line voltage.
0 VDC.
12VDC.
100 mV.
The correct input voltage applied to the V250-S and the input power switch (S1) in the ON position.
When remote trigger circuit is “closed”.
When remote trigger circuit is “open”.
Machine loaded to 120 Amps
Check for 15VDC control board supply voltage.
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Lead #303 (7J3)+
to
Lead #375 (1J3)-
INVERTEC V250-S
15VDC.
The correct input voltage applied to the V250-S and the input power switch (S1) in the ON position.
Page 66
F-34
NOTES
F-34
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INVERTEC V250-S
Page 67
F-35
TROUBLESHOOTING & REPAIR
PROTECTION CIRCUIT TEST
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-35
TEST DESCRIPTION
This check will aid the technician in the understanding and evaluation of the V250-S protec­tion circuit.
MATERIALS NEEDED
Voltmeter/ohmmeter (Multimeter) Machine wiring diagram Protection circuit simplified wiring diagram
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INVERTEC V250-S
Page 68
F-36
TROUBLESHOOTING & REPAIR
PROTECTION CIRCUIT TEST (continued)
F-36
TEST PROCEDURE
1. Remove main input power to the V250-S.
2. Perform
Procedure
Section.
Filter Capacitor Discharge
detailed in Maintenance
8J2
J1
J2 J5 J3 J4
6J2
1J2
2J2
3. Locate and familiarize yourself with the leads and pin locations in plug J2 on the control board and also plug J6 on the power board. See Figures F.10. and F.11.
G2666-[ ]
V250S CONTROL
Figure F.10 Control Board Plug J2 Test Points
#313 (5J6)
#309 (6J6)
#310 (3J6)
#311 (4J6)
#308 (1J6)
#307 (2J6)
PLUG J6
205
208
209
V250S POWER G2684
J6
204
201
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Figure F.11 Power Board Plug J6 Test Points
INVERTEC V250-S
Page 69
F-37
TROUBLESHOOTING & REPAIR
PROTECTION CIRCUIT TEST (continued)
F-37
4. The following tests will be performed with the input power applied to the V250-S. BE CAREFUL. ALWAYS
REMOVE INPUT POWER AND PERFORM FILTER CAPACITOR DISCHARGE PROCEDURE BEFORE TOUCHING ANY MACHINE COMPONENT.
5. Apply input power and turn ON the V250-S.
6. Check for 0 to 1 VDC at leads #311(4J6)+ to #313(5J6)- at the power board. If the correct voltage is present go to step #7.
If 15VDC is present the overvoltage protection circuit has not been satis­fied. Perform the
Test
. If the capacitor balance is
Capacitor Balance
good and the overvoltage protection circuit has NOT been satisfied the power board may be faulty. Replace.
7. Check for 0 to 1VDC at leads #311(2J2)+ to #313(8J2)- at the con­trol board. If the correct voltage is present go to step 8.
If the correct voltage is present at the power board but not at the control board check associated leads and connections.
8. Check for 15VDC at leads #309(1J2)+ to #310(6J2)- at the con­trol board. If the correct voltage is present check for 15VDC at leads #309(6J6) + to #310(3J6)- at the power board.
If the correct voltage is present at the control board but not at the power board check the associated leads and connections.
If the correct voltage, 15VDC, is not present at the control board the con­trol board may be faulty. Perform the
Control Board Voltage Test
.
9. If 15VDC IS present at leads #309(6J6)+ to #310(3J6)- at the power board the input relay (1CR), should activate (pull-in) and apply full input power to the filter capacitors.
If this does not take place the power board may be faulty. Replace.
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POWER BOARD
O
D
V
E
E
T
R
E
V
C
O
T
L
I
T
O
A
N
G E
1CR
CHARGE
RELAY
PROTECTION CIRCUIT (SIMPLIFIED)
TIMER
(4J6)
)
5J6(
(6J6)
(3J6)
INVERTEC V250-S
#311
#313
#309
#310
(2J2)
(8J2)
(1J2)
(6J2)
CONTROL BOARD
+15VDC
+15VDC
Page 70
F-38
NOTES
F-38
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INVERTEC V250-S
Page 71
F-39
TROUBLESHOOTING & REPAIR
CAPACITOR BALANCE TEST
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-39
TEST DESCRIPTION
This test will help the technician to determine if the input filter capacitors are being charged equally and to the correct voltage levels. Note: This test should only be conducted with the V250-S reconnect switch and “A” jumper configured for 380VAC and above.
MATERIALS NEEDED
Voltmeter/ohmmeter (Multimeter) Machine wiring diagram.
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INVERTEC V250-S
Page 72
F-40
TROUBLESHOOTING & REPAIR
CAPACITOR BALANCE TEST (continued)
F-40
TEST PROCEDURE
1. Remove main input power to the V250-S.
2. Perform
Procedure
Section.
3. Put the mode switch S2 in the SMAW (soft) position and put the Local/Remote switch S3 in the LOCAL position.
4. Put the Output Control R3 at the minimum position.
5. Locate and familiarize yourself with the capacitor test locations on the power board. See Figure F.12.
Filter Capacitor Discharge
detailed in Maintenance
6. The following tests will be performed with the input power applied to the V250-S.
BE CAREFUL. ALWAYS REMOVE THE INPUT POWER AND PERFORM FILTER CAPACITOR DISCHARGE PROCEDURE BEFORE TOUCHING ANY MACHINE COMPONENT.
7. Apply the correct input power†and turn ON the V250-S.
† Note: This test should only be conducted
with the V250-S reconnect switch and “A” jumper configured for 380VAC and above.
CAPACITOR (C2) TERMINALS
201
204
V250S POWER G2684
209
208
205
207A
203A
+
202A
DANGER
HIGH VOLTAGE CAN KILL
+
206
CAPACITOR (C1) TERMINALS
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Figure F.12 Power Board and Capacitor Test Locations
INVERTEC V250-S
Page 73
F-41
TROUBLESHOOTING & REPAIR
CAPACITOR BALANCE TEST (continued)
F-41
8. Check for the appropriate voltages outlined in Table F.6. Note: Voltages may vary with the input line voltage.
In the event the capacitor voltage is too high or not balanced (within 20VDC) the protection circuit will pre­vent output. The overvoltage trip set­ting is nominal line voltage (230/460) +15%. Reset occurs about 3% lower (230/460) +12%.
TABLE F.6 Capacitor Voltages
INPUT APPLIED TERMINALS
460VAC 325VDC 440VAC 311VDC 415VAC 293VDC 380VAC 269VDC
9. If the capacitor voltages are NOT balanced within 20VDC the capaci­tors may be need “conditioning” . See
maintenance
The capacitors or other components on the power board may be faulty. Replace power board.
EXPECTED VOLTS
DC AT CAPACITOR
section.
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NOTE
The following machine parts must be replaced in matched sets If Capacitor C1 is found to be defective, both Capacitors C1 and C2 must be replaced at the same time:
INVERTEC V250-S
Page 74
F-42
NOTES
F-42
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INVERTEC V250-S
Page 75
F-43
TROUBLESHOOTING & REPAIR
CONTROL BOARD REMOVAL AND REPLACEMENT
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-43
MATERIALS NEEDED
Small needle-nose pliers Small screwdriver 5/16” nut-driver
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INVERTEC V250-S
Page 76
F-44
TROUBLESHOOTING & REPAIR
CONTROL BOARD REMOVAL AND REPLACEMENT (continued)
F-44
PROCEDURE
1. Remove input power to the V250-S.
2. Perform
Procedure
Section.
3. Locate the control board and the five molex type plugs that are connected to it. See Figure F.13.
4. Carefully remove the five molex type plugs by depressing the locking tabs and gently extracting the plugs from the P.C. board receptacles.
5. Using the needle nose-pliers and small screwdriver gently remove the control board from the six mounting pins by depressing the tabs on the mounting pins and sliding the board from the pins. See Figure F.13.
Filter Capacitor Discharge
detailed in Maintenance
Note: Be sure to observe static elec­tricity precautions when handling P.C. boards.
6. When replacing the control board align the mounting holes with the mounting pins and gently slide the P.C. board onto the mounting pins until the board “snaps” onto the mounting pins.
Note: Be sure to observe static elec­tricity precautions when handling P.C. boards.
7. Replace the five molex type plugs in their appropriate receptacles.
8. Inspect, clear and secure all leads in preparation for case wrap-around reassembly.
9. Using the 5/16” nut-driver replace the case wrap-around.
J1
J2 J5 J3 J4
SIX MOUNTING TABS
V250S CONTROL
G2666-[ ]
DEPRESS LOCKING TAB ON MOUNTING PIN
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Figure F.13 Control Board Plugs and Mounting Pins
INVERTEC V250-S
Page 77
F-45
TROUBLESHOOTING & REPAIR
POWER BOARD REMOVAL AND REPLACEMENT
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-45
MATERIALS NEEDED
5/16” nut-driver 1/4” nut-driver 7/16” wrench 3/16” Allen type wrench
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INVERTEC V250-S
Page 78
F-46
TROUBLESHOOTING & REPAIR
POWER BOARD REMOVAL AND REPLACEMENT (continued)
F-46
PROCEDURE
1. Remove input power to the V250-S.
2. Perform
Procedure
Section.
3. Locate the power board, the molex type plug J6, the five leads with push-on connectors and the four capacitor leads that are connected to the power board.
4. Carefully remove leads (with push­on connectors) #201, #204, #205, #208, and #209 from the power board.
Filter Capacitor Discharge
detailed in Maintenance
5. Remove plug J6 by depressing the locking tab and removing it from the power board.
6. With the 7/16” wrench remove the four bolts and washers from the filter capacitor terminals.
Remove leads #202A, #207A, #203A and #206 from the capacitor terminals.
See Figure F.14. Cut any neces­sary cable ties.
201
204
J6
V250S POWER G2684
209
208
207A
203A
+
202A
4 SOCKET HEAD CAP SCREWS
DANGER
HIGH VOLTAGE CAN KILL
+
206
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205
Figure F.14 Power Board Lead Locations
INVERTEC V250-S
Page 79
F-47
TROUBLESHOOTING & REPAIR
POWER BOARD REMOVAL AND REPLACEMENT (continued)
F-47
7. Using the 1/4” nut-driver remove the two screws holding the P.C. board to the heat sink mounting bracket.
8. With the 3/16” Allen wrench remove the four socket head cap screws and washers holding the power board to the large aluminum heat sink.
9. Carefully remove the power board taking note as to the amount of heat sink compound used between the IGBTs and the large aluminum heat sink. Note: Be sure to observe static electricity precautions when handling P.C. boards.
If the filter capacitors are to be removed see
Removal and Replacement
POWER BOARD REPLACEMENT PROCEDURE
Filter Capacitor
.
13. Assemble the leads #202A, #207A, #203A and #206 to their respective capacitor terminals using the bolts, lockwashers and 7/16” wrench. Torque to 50 - 60 IN. Lbs.
14. Using the 1/4” nut-driver install the two screws holding the P.C. board to the heat sink mounting bracket.
15. Connect leads #201, #204, #205, #208, and #209 to their appropriate terminals.
16. Replace plug J6 into power board.
17. Replace any previously removed cable ties.
18 Inspect, clear and secure all leads
in preparation for case wrap-around reassembly.
10. Apply a thin coat of Dow Corning 340 heat sink compound (Lincoln E1868) to the filter capacitor termi­nals. Do not apply to screw threads or threaded area of terminals.
11. When replacing the power board
apply a thin coating (.005 to .010) of Dow Corning 340 heat sink compound (Lincoln E1868) to the mating surfaces between the IGBTs and the aluminum heat sink. Compound is NOT permitted on the screw heads or mounting hole threads. The mating surfaces must be clean and free of any for­eign material.
12. Install the power board and tighten the four cap head screws. Torque the cap head screws to 40 to 48 IN. Lbs. Note: Before tightening make certain the capacitor terminals are aligned with their respective holes in the power P.C. board.
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INVERTEC V250-S
Page 80
F-48
NOTES
F-48
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INVERTEC V250-S
Page 81
F-49
TROUBLESHOOTING & REPAIR
FILTER CAPACITOR REMOVAL AND REPLACEMENT
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-49
MATERIALS NEEDED
5/16” nut-driver Slot head screwdriver
MATCHED PARTS
The following machine parts must be replaced in matched sets If Capacitor C1 is found to be defective, both Capacitors C1 and C2 must be replaced at the same time:
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INVERTEC V250-S
Page 82
F-50
TROUBLESHOOTING & REPAIR
FILTER CAPACITOR REMOVAL AND REPLACEMENT (continued)
F-50
PROCEDURE
1. Remove input power to the V250-S.
2. Perform
Procedure
Section.
3 . Perform
Procedure
4. Using the 5/16’ nut-driver remove
the two screws from the top rear of the case back. See Figure F.15.
Filter Capacitor Discharge
detailed in Maintenance
Power Board Removal
in this section.
5. Using the 5/16” nut-driver remove the two screws from the top front of the case front panel. See Figure F.15.
6. Using the slot head screwdriver carefully disengage the heatsink/power board mounting bracket from the top center panel. This can be accomplished by sliding the bracket assembly towards the rear of the machine while at the some time gently lifting up on the top center panel. See Figure F.15.
REMOVE CASE FRONT  SCREWS
TOP CENTER PANEL
MOUNTING BRACKETS
REMOVE CASE BACK SCREWS
POWER BOARD
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Figure F.15 Heatsink/Power Board Removal
INVERTEC V250-S
Page 83
F-51
TROUBLESHOOTING & REPAIR
FILTER CAPACITOR REMOVAL AND REPLACEMENT (continued)
7. Once the top of the bracket assem­bly is disengaged from the top center panel the bracket assembly can be removed from the bottom of the case by sliding the bracket assembly towards the front of the machine. The locking tab on the bottom of the bracket will have to be lifted slightly to enable the assembly to slide freely towards the front.
8. With the bracket assembly out of the machine the filter capacitors can be removed by loosening the capacitor clamps and sliding the filter capaci­tors out of the assembly.
Note: Before removing the capaci­tors precisely mark where the capac­itors are positioned in the clamp. This is important so the new capaci­tor terminals will align with the holes in the power board. Also mark polarity configuration for reassembly purposes.
9. Install the new capacitors taking note of position in the clamp and also polarity location.
10. Using the slot head screwdriver
tighten the clamps.
11. Install the heatsink/power board bracket assembly (with new capaci­tors installed) into the machine by first positioning the bottom of the bracket into the slots in the case bottom and sliding the bracket assembly towards the rear of the machine.
12. Carefully position the top of the heatsink/power board bracket assembly into the top center panel and slide the panel towards the rear of the machine while holding the heatsink/power board mounting bracket in place.
13. Using the 5/16’ nut-driver replace
the two screws at the top rear of the case back. See Figure F.15.
14. Using the 5/16” nut-driver replace
the two screws at the top front of the case front panel. See Figure F.15.
15. Perform
Replacement Procedure
section.
Power Board
in this
F-51
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INVERTEC V250-S
Page 84
F-52
NOTES
F-52
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INVERTEC V250-S
Page 85
F-53
TROUBLESHOOTING & REPAIR
INPUT RECTIFIER BRIDGE REMOVAL AND REPLACEMENT
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-53
MATERIALS NEEDED
3/16” Allen type wrench Phillips head screwdriver 7/16” Box wrench Torque wrench
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INVERTEC V250-S
Page 86
F-54
TROUBLESHOOTING & REPAIR
INPUT RECTIFIER BRIDGE REMOVAL AND REPLACEMENT (continued)
F-54
PROCEDURE
1. Remove input power to the V250-S.
2. Perform
Procedure
Section.
3. Locate the input rectifier and the leads connected to it. See Figure F.16.
4. Identify and mark the leads connect­ed to the rectifier terminals.
Filter Capacitor Discharge
detailed in Maintenance
CAP HEAD  MOUNTING  SCREWS
5. With the Phillips head screwdriver remove the eight leads connected to the rectifier terminals.
6. Using the 3/16” Allen wrench and 7/16” box wrench remove the two cap head screws, washers and nuts mounting the input rectifier bridge to the center panel assembly.
#207 #207A
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A
B
C
#209
Figure F.16 Input Rectifier Lead Locations
INVERTEC V250-S
Page 87
F-55
TROUBLESHOOTING & REPAIR
INPUT RECTIFIER BRIDGE REMOVAL AND REPLACEMENT (continued)
7. Carefully remove the input rectifier bridge.
8. When installing a new input rectifier apply a thin coating of Dow Corning 340 Heat Sink Compound (Lincoln E1868) to the mating surfaces. Torque the mounting cap screws and nuts to 44 IN-LBS.
9. Reconnect the eight leads to the cor­rect terminals and torque the phillips head screws to 31 IN-LBS.
F-55
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INVERTEC V250-S
Page 88
F-56
NOTES
F-56
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INVERTEC V250-S
Page 89
F-57
TROUBLESHOOTING & REPAIR
OUTPUT DIODE ASSEMBLY REMOVAL AND REPLACEMENT
(MACHINE CODES BELOW 10150)
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-57
MATERIALS NEEDED
Slot head screwdriver 5/16” nut-driver 7/16” wrench Wire cutters 3/8” wrench
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INVERTEC V250-S
Page 90
F-58
TROUBLESHOOTING & REPAIR
OUTPUT DIODE ASSEMBLY REMOVAL AND REPLACEMENT
(MACHINE CODES BELOW 10150)
(continued)
F-58
PROCEDURE
1. Remove input power to the V250-S.
2. Perform
Procedure
Section.
3. Locate output diode assembly and associated leads. See Figure F.17.
4. Cut the necessary wire ties and slide the sleeving from the four wire con­nections to be disassembled. See Figure F.17
5. Label the leads for identification pur­poses for reassembly.
Filter Capacitor Discharge
detailed in Maintenance
6. Using the 7/16” wrench remove the bolts, nuts and washers from two of the splices.
7. Using the 3/8” wrench and slot head screwdriver disassemble the other two splices.
8. Using the 7/16” wrench remove the bolt and washers connecting the out­put cable to the diode heat sink. Be sure to take note of the small resistor connection at the same point. See Figure F.17.
9. With the 5/16” nut-driver remove the
two screws from the top rear case back. See
Figure F.15
.
SNUBBER RESISTORS
7/16 BOLT
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SLEEVED SPLICES
Figure F.17 Output Diode Assembly and Leads
INVERTEC V250-S
Page 91
F-59
TROUBLESHOOTING & REPAIR
OUTPUT DIODE ASSEMBLY REMOVAL AND REPLACEMENT
(MACHINE CODES BELOW 10150)
(continued)
LOCKING TABS
F-59
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Figure F.18 Heatsink Removal
10. Using the slot head screwdriver carefully disengage the output diode heat sink mounting bracket from the top center panel. Also dis­engage the bottom heat sink mounting bracket from the support bracket. This can be accomplished by lifting the locking tab and sliding the heat sink assembly towards the rear of the machine. See Figure F.18.
11. Carefully remove the output diode assembly from the V250-S.
12. Remove the two heat sink holders from the heat sink/diode assembly.
13. Assemble the two heat sink holders to the new heat sink/diode assem­bly.
14. Install the new output diode assem­bly into position and slide it towards the front of the machine until the locking tabs (both top and bottom) are engaged. See Figure F.18.
INVERTEC V250-S
15. Install the two screws into the top rear case back. See
16 Using the 7/16” wrench, bolt and
washers connect the output cable to the diode heat sink. Be sure to take note of the small resistor connection at the same point. See
F.17
.
17. Using the 7/16” wrench, bolts, nuts and washers assemble and tighten the two splices.
18. Using the 3/8” wrench and slot head screwdriver assemble and tighten the other two splices.
19. Position sleeving and secure with cable ties. Clear all leads and pre­pare unit for reassembly of wrap­around case.
Figure F.15
Figure
.
Page 92
F-60
NOTES
F-60
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INVERTEC V250-S
Page 93
F-61
TROUBLESHOOTING & REPAIR
OUTPUT DIODE ASSEMBLY REMOVAL AND REPLACEMENT
(MACHINE CODES ABOVE 10150)
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-61
MATERIALS NEEDED
7/16” wrench 1/8” Allen type wrench Torque wrench
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INVERTEC V250-S
Page 94
F-62
TROUBLESHOOTING & REPAIR
OUTPUT DIODE ASSEMBLY REMOVAL AND REPLACEMENT
(MACHINE CODES ABOVE 10150)
(continued)
F-62
PROCEDURE
1. Remove input power to the V250-S.
2. Perform
Procedure
Section.
3. Locate output diode assembly and associated leads. See Figure F.19.
4. Label the leads for identification pur­poses for reassembly.
Filter Capacitor Discharge
detailed in Maintenance
7/16 MOUNTING BOLTS
5. Using the 7/16” wrench remove the bolts, nuts and washers from the lead terminals of the module to be replaced. Clear leads and take care­ful note of lead placement.
DIODE MODULES
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7/16 BOLTED CONNECTIONS
Figure F.19 Output Diode Assembly and Leads
INVERTEC V250-S
Page 95
F-63
TROUBLESHOOTING & REPAIR
OUTPUT DIODE ASSEMBLY REMOVAL AND REPLACEMENT
(MACHINE CODES ABOVE 10150)
(continued)
F-63
6. Using 7/16” wrench remove the top and bottom mounting bolts and associated washers from the diode module to be replaced.
7. Using 1/8” Allen wrench remove the center socket head cap screw from the diode module to be replaced.
8. Carefully remove the diode module.
9. To install the new module first make sure the heat sink surface is clean and free of dirt.
10. Apply a thin even coating (.004 to
.010 IN.) of thermal compound Penetrox A13 (Lincoln E2529) to the bottom surface of the base plate. Keep the compound away from the mounting hole areas.
11. Apply a small amount of Loctite
#271 (Lincoln E1777-1) to the first three threads of the socket head cap screw.
13. Run the center cap screw in by hand until it makes contact with the surface of the module. Do not
torque down yet!
14. Tighten the top and bottom screws to between 5.0 and 10.0 IN-LBS.
15. Tighten the center cap screw to between 12 and 18 IN-LBS.
16. Further tighten the top and bottom screws to between 30 and 40 IN-LBS.
17. Connect the leads to the proper ter­minals and tighten the screws to between 30 to 40 IN-LBS. Do not stress the module terminals when making these connections.
18. Clear all leads and prepare unit for reassembly of wrap-around case.
12. Start threading the top and bottom screws and associated washers by hand. Also start the center socket head cap screw and associated washer.
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INVERTEC V250-S
Page 96
F-64
NOTES
F-64
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INVERTEC V250-S
Page 97
F-65
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER REMOVAL AND REPLACEMENT
(MACHINE CODES BELOW 10150)
WARNING
Service and repair should be performed only by Lincoln Electric factory trained per­sonnel. Unauthorized repairs performed on this equipment could result in danger to the technician or the machine operator and will invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety notes and precau­tions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric service department for technical troubleshooting assistance before you proceed. Call (216) 383-2531 or (800) 833-9353 (WELD).
_____________________________________________________________
F-65
MATERIALS NEEDED
7/16” Wrench 3/8” Wrench Wire cutters 3/4” Wrench Slot head screwdriver
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INVERTEC V250-S
Page 98
F-66
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER REMOVAL AND REPLACEMENT
(MACHINE CODES BELOW 10150)
(continued)
F-66
PROCEDURE
1. Remove input power to the V250-S.
2. Perform
Procedure
Section.
3. Locate main transformer and associ-
ated primary leads. See Figure F.20.
4. Disconnect transformer primary
leads #201, #204, #205 and #208 from the power board.
Note: Leads #204 and #205 will have to be removed from the T3 cur­rent transformer. Cut any necessary
Filter Capacitor Discharge
detailed in Maintenance
cable ties. Be sure to note the
direction that the leads are thread­ed through the current trans­former. Upon reassembly the leads must be threaded through correctly.
5. Locate main transformer and associ­ated secondary leads, reactor leads, and shunt connections. See Figure F.21.
201
204
T3 CURRENT TRANSFORMER
MAIN TRANSFORMER
208
205
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Figure F.20 Main Transformer Right Side
INVERTEC V250-S
Page 99
F-67
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER REMOVAL AND REPLACEMENT
(MACHINE CODES BELOW 10150)
(continued)
F-67
MAIN TRANSFORMER SECONDARY LEADS
Figure F.21 Main Transformer Left Side
6. Disconnect and clear the shunt sensing leads from the control board (plug J4).
7. Disconnect the thermostat leads from the thermostat mounted on the shunt assembly.
8. With the 3/4” wrench remove the shunt assembly from the negative output terminal. Take note of the by­pass connection on the negative ter­minal. Clear the shunt to allow access to the main transformer and lead connections. Cut any neces­sary cable ties.
9. With the 3/4” wrench remove the two secondary leads from the positive output terminal. Take note of the by­pass connection on the positive ter­minal.
10. Locate and cut the necessary wire ties and slide the sleeving from the four transformer secondary and reactor lead splices.
11. With slot head screwdriver and 3/8” nut-driver remove the two reactor leads from output rectifier leads. Label the leads for reassembly.
12. Using the 7/16” wrench remove the secondary leads from the output rectifier leads.
Label the leads and note washer and lead placement for reassembly.
13. With 3/8” wrench remove the two screws mounting the transformer assembly to the base of the machine. See The machine will have to be tilted on its side to gain access to the bottom of the unit.
Figure F.22
. Note:
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INVERTEC V250-S
Page 100
F-68
TROUBLESHOOTING & REPAIR
MAIN TRANSFORMER REMOVAL AND REPLACEMENT
(MACHINE CODES BELOW 10150)
(continued)
MAIN TRANSFORMER  LOCKING MOUNTING TABS
F-68
MAIN TRANSFORMER  MOUNTING SCREWS
Figure F.22 Main Transformer Mountings
14. Using the slot head screwdriver unclip the locking tabs and slide the transformer towards the front of the machine until it is free of the slots in the bottom of the machine.
Note: The machine will have to be tilted on its side to gain access to the bottom of the unit.
15. With the main transformer loose from the base carefully tilt and remove the transformer from the left side of the machine.
16. Install the new transformer by tilting and carefully positioning it in place in the slots in the case bottom. Slide towards the rear of the machine until the locking tabs are in place.
Note: The machine will have to be tilted on its side to gain access to the bottom of the unit.
18. Using the 7/16” wrench reassemble the two secondary leads to the out­put rectifier leads. Note lead and washer placement and lead labels.
19. Using the slot head screwdriver and 3/8” nut-driver reassemble the two reactor leads to the output rec­tifier leads. Note lead labels.
20. Replace the sleeving on the four connections and replace the cable ties.
21. With the 3/4” wrench assemble the two secondary leads to the positive output terminal.
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17. With the 3/8” wrench replace the two transformer mounting screws.
INVERTEC V250-S
Take note of the by-pass connec­tion on the positive output terminal.
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