Lincoln Electric IM520 User Manual

IM520-B

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SQUARE WAVE TIG 255

For use with machines having Code Number 10022 thru 10026 & 10134, 10451,10452,10453.

Safety Depends on You

Lincoln arc welding and cutting
equipment is designed and built
wi th saf ety in mind. Howe ver ,
you r o v e rall s afet y ca n b e
increased by proper installation ...
and thoughtful operation on your
par t . DO NOT IN S TALL,

OPE R A TE O R RE P AIR T HIS
EQU I P MENT WIT H O UT
READING THIS MANUAL AND
THE SAF ETY P RECAU TIONS
CO NTA INE D THROUG HOU T.

And , m o s t i mport a n tly, thi n k
before you act and be careful.

January, 1997

World's Leader in Welding and Cutting Products Premier Manufacturer of Industrial Motors

OPERATOR’S MANUAL

Sales and Service through Subsidiaries and Distributors Worldwide

22801 St. Clair Ave. Cleveland, Ohio 44117-1199 U.S.A. Tel. [phone]

SAFETY

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.

____________________________________________________

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.

___________________________________________________

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.

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. Nev er c oil 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

– 2 –

SAFETY

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

– 3 –

SAFETY

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.

Sparks and spatter are thrown from the welding arc. Wear oil

6.f.
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.

– 4 –

Mar ‘95

SAFETY

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.

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.

5. Toujours porter des lunettes de sécurité dans la zone de
soudage. Utiliser des lunettes avec écrans lateraux dans les

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
place.

Mar. ‘93

– 5 –

for selecting a QUALITY product by Lincoln Electric. We want you

Thank You

to take pride in operating this Lincoln Electric Company product

••• as much pride as we have in bringing this product to you!

Please Examine Carton and Equipment For Damage Immediately

When this equipment is shipped, title passes to the purchaser upon receipt by the carrier. Consequently, Claims
for material damaged in shipment must be made by the purchaser against the transportation company at the
time the shipment is received.

Please record your equipment identification information below for future reference. This information can be
found on your machine nameplate.

Model Name & Number _____________________________________

Code & Serial Number _____________________________________

Date of Purchase _____________________________________

Whenever you request replacement parts for or information on this equipment always supply the information
you have recorded above.

Read this Operators Manual completely before attempting to use this equipment. Save this manual and keep it
handy for quick reference. Pay particular attention to the safety instructions we have provided for your protection.
The level of seriousness to be applied to each is explained below:

WARNING

This statement appears where the information must be followed exactly to avoid serious personal injury or
loss of life.

CAUTION

This statement appears where the information must be followed to avoid minor personal injury or damage to

this equipment.

– 6 –

TABLE OF CONTENTS

Page

Safety .....................................................................................................................2-6

Installation................................................................................................................8-12

Technical Specifications ............................................................................................8

Input and Output Specifications
Cable and Fuse Sizes

Physical Dimensions

Location .....................................................................................................................9

Machine Grounding....................................................................................................9

Input Connections....................................................................................................10

Output Connections.................................................................................................11

Operation................................................................................................................13-23

Safety Instructions ...................................................................................................13

Graphic Symbols ................................................................................................14-15

General Description.................................................................................................16

Design Features and Advantages............................................................................16

Welding Capability...................................................................................................17

Limitations................................................................................................................17

Controls and Settings...............................................................................................18

Hand and Foot Amptrol Operation...........................................................................20

Welding Operation..............................................................................................20-23

Tig Welding Guidelines.......................................................................................20

Tig Welding Sequence of Operation (2 Step Mode)...........................................21

Tig Welding Sequence of Operation (4 Step Mode)...........................................22

Advanced Tig Welding Features.........................................................................22

Stick Welding......................................................................................................23

Auxillary Power........................................................................................................23

Overload Protection.................................................................................................23

Accessories.................................................................................................................24

Maintenance...........................................................................................................25-26

Safety Precautions...................................................................................................25

Routine and Periodic Maintenance..........................................................................25

General Assembly Exploded View...........................................................................26

Troubleshooting ....................................................................................................27-34

How To Use Troubleshooting Guide........................................................................27

Troubleshooting Guide .......................................................................................28-34

Wiring Diagrams ....................................................................................................35-36

Parts Manual .................................................................................................APPENDIX

– 7 –

INSTALLATION

TECHNICAL SPECIFICATIONS - SQUARE WAVE TIG 255

INPUT - SINGLE PHASE ONLY

Standard

Voltage

208/230/460/1/60

230/460/575/1/60
200/240/400/1/50/60
220/380/440/1/50/60
380/415/500/1/50/60
220/380/415/1/50/60

Input Current at
Rated Output

81/74/37
74/37/30
85/77/44
77/45/39
45/41/33
77/45/41

RATED OUTPUT

(1)

Code

Number

10022
10023
10024
10452
10453
10451

Duty Cycle

40% Duty Cycle

NEMA Class II (40)

60% Duty Cycle

100% Duty Cycle

Welding Current Range

(Continuous)

5-315 Amps

AC and DC

Fuse

Input

Voltage /

Frequency

208/60
230/60
460/60

575/60
200/50/60
220/50/60
380/50/60
400/50/60
415/50/60
440/50/60
500/50/60

(Super Lag)

or Breaker

Size

125
100

50

50
125
100

70

60

60

60

50

Amps

Volts at Rated Amperes

255
200

150

OUTPUT

Constant Open
Circuit Voltage

115 Volts AC, 10 Amps

Stick OCV: 76

TIG OCV: 53

RECOMMENDED INPUT WIRE AND FUSE SIZES

For all Stick, DC TIG, and Balanced AC TIG

Welding at 255A/30V/40% Duty Cycle

Based on the 1993 US. National

Electrical Code

Type 75°C

Input

Ampere

Rating on

Nameplate

81
74
37
30
85
77
46
43
41
39
34

Type 75°C

Copper Wire in

Conduit AWG

(IEC) Sizes

6 (16mm2)
6 (16mm2)
10 (6mm2)
10 (6mm2)
6 (16mm2)
6 (16mm2)
8 (10mm2)
10 (6mm2)
10 (6mm2)
10 (6mm2)
10 (6mm2)

Copper Ground
Wire in Conduit

AWG (IEC)

Sizes

6 (16mm2)
8 (10mm2)
10 (6mm2)
10 (6mm2)
6 (16mm2)
8 (10mm2)
8 (10mm2)
10 (6mm2)
10 (6mm2)
10 (6mm2)
10 (6mm2)

For Unbalanced AC TIG Welding Above 180

Amps, 255A/16V/40% Duty Cycle, Auto

Balance Based on the 1993 U.S. National

Electrical Code

Copper Wire in

Input

Amperes

102

92
46
37

105

96
55
53
51
48
42

Conduit AWG

30
28

26

Auxiliary Power

220Volts AC, 2 Amps

(50/60 Hz. machines only)

Type 75°C

Type 75°C

(IEC) Sizes

4 (25mm2)
4 (25mm2)
8 (10mm2)
10 (6mm2)
4 (25mm2)
4 (25mm2)
8 (10mm2)
8 (10mm2)
8 (10mm2)
8 (10mm2)
10 (6mm2)

Copper Ground
Wire in Conduit

AWG (IEC)

6 (16mm2)
6 (16mm2)
10 (6mm2)
10 (6mm2)
6 (16mm2)
8 (10mm2)
8 (10mm2)
10 (6mm2)
10 (6mm2)
10 (6mm2)
10 (6mm2)

Sizes

PHYSICAL DIMENSIONS

Height Width Depth Weight

30.5 in. 19.0 in. 30.0 in.
(Lift bail, add 3.5 in) 300 lbs

775 mm 485 mm 760 mm

(Lift bail, add 90 mm)

(1)

Unbalanced TIG welding above 180 amps will draw higher input currents; see Supply Connections section.

– 8 –

(137 kg)

INSTALLATION

Read entire installation section before starting
installation.

Safety Precautions

WARNING

ELECTRIC SHOCK can kill.

• Only qualified personnel should

perform this installation.

• Turn the input power OFF at the

disconnect switch or fuse box
before working on this
equipment.

• Do not touch electrically hot

parts.

• Always connect the Square Wave

TIG 255 grounding terminal
(located on the bottom of the
input connection box) to a good
electrical earth ground.

MACHINE GROUNDING AND HIGH
FREQUENCY INTERFERENCE
PROTECTION

The frame of the welder must be grounded. A ground
terminal marked with the symbol is located at
the bottom of the input box for this purpose. See your
local and national electrical codes for proper
grounding methods.

The spark gap oscillator in the high frequency
generator, being similar to a radio transmitter, can be
blamed for many radio, TV and electronic equipment
interference problems. These problems may be the
result of radiated interference. Proper grounding
methods can reduce or eliminate radiated
interference.

Radiated interference can develop in the following
four ways:

1. Direct interference radiated from the welder.

2. Direct interference radiated from the welding leads.

SELECT SUITABLE LOCATION

Place the welder where clean cooling air can freely
circulate in through the rear louvers and out through
the side louvers. Dirt, dust or any foreign material that
can be drawn into the welder should be kept at a
minimum. Failure to observe these precautions can
result in excessive operating temperatures and
nuisance shut-downs.

STACKING

Square Wave TIG 255’s cannot be stacked.

TILTING

Each machine must be placed on a secure, level
surface, either directly or on a recommended
undercarriage. The machine may topple over if this
procedure is not followed.

ENVIRONMENTAL PROTECTION

3. Direct interference radiated from feedback into the
power lines.

4. Interference from re-radiation of “pickup” by
ungrounded metallic objects.

Keeping these contributing factors in mind, installing
equipment per the following instructions should
minimize problems.

1. Keep the welder power supply lines as short as
possible and completely enclose them in rigid
metallic conduit or equivalent shielding for a
minimum distance of 50 feet (15.2m). There
should be good electrical contact between this
conduit and the welder. Both ends of the conduit
should be connected to a driven ground and the
entire length should be continuous.

2. Keep the work and electrode leads as short as
possible and as close together as possible.
Lengths should not exceed 25 ft (7.6m). Tape the
leads together when practical.

Square Wave TIG 255 power sources carry an IP21
protection rating. They are rated for use in rain­sheltered environments.

3. Be sure the torch and work cable rubber coverings
are free of cuts and cracks that allow high
frequency leakage. Cables with high natural
rubber content, such as Lincoln Stable-Arc® better
resist high frequency leakage than neoprene and
other synthetic rubber insulated cables.

– 9 –

INSTALLATION

1

4

3

2

4. Keep the torch in good repair and all connections
tight to reduce high frequency leakage.

5. The work terminal must be connected to a ground
within ten feet of the welder, using one of the

following methods:
a) A metal underground water pipe in direct

contact with the earth for ten feet or more.

b) A 3/4” (19mm) galvanized pipe or a 5/8”

(16mm) solid galvanized iron, steel or copper
rod driven at least eight feet into the ground.

The ground should be securely made and the
grounding cable should be as short as possible
using cable of the same size as the work cable, or
larger. Grounding to the building frame electrical
conduit or a long pipe system can result in re­radiation, effectively making these members
radiating antennas.

6. Keep all access panels and covers securely in
place.

See Figure 1 for the location of the rating plate, the
entry hole, and the reconnect panel.

FIGURE 1 - REAR PANEL

7. All electrical conductors within 50 ft (15.2m) of the
welder should be enclosed in grounded rigid
metallic conduit or equivalent shielding. Flexible
metallic conduit is generally not suitable.

8. When the welder is enclosed in a metal building,
several good earth driven electrical grounds (as in
5 (b) above) around the periphery of the building
are recommended.

Failure to observe these recommended installation
procedures can cause radio or TV interference
problems and result in unsatisfactory welding
performance resulting from lost high frequency
power.

INPUT 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.

1. RATING PLATE 3. 220V RECEPTACLE & BREAKER

2. INPUT ENTRY & (50/60 HZ MACHINE ONLY)
RECONNECT PANEL 4. 115V RECEPTACLE & BREAKER

Have a qualified electrician connect the input leads to
L1 and L2 of the input panel in accordance with all
local codes and national electrical codes, and the
connection diagram located on the inside of the cover.
Use a single phase line or one phase of a two or three
phase line.

On multiple input voltage welders, be sure the
reconnect panel is connected per the following
instructions for the voltage being supplied to the
welder.

CAUTION

Welder supply line entry provision is in the case rear
panel with a removable cover over the input
connection panel area. Entry is through a 1.7 in
(43mm) diameter hole in the case back. European
machines have a plastic bushing good for 3 - 10mm
conductors. For larger input conductors a customer
supplied plastic bushing should be used if required by
local or national code specifications.

2

Failure to follow these instructions can cause
immediate failure of components within the welder.

___________________________________________

– 10 –

INSTALLATION

DC

DC

AC

O

I

POWER

WARNING

ELECTRODE

WORK

GAS

IN

OUT

WATER

IN

OUT

DO NOT SWITCH
WHILE WELDING

L9119-1

L9119-2

REMOTE

1

2

3

4

5

6

7

8

Welders are shipped connected for the highest input
voltage as listed on the rating Plate. To change this
connection for a different input voltage, reconnect the
power strap (P) to the terminal corresponding to the
input voltage used. Designations on reconnect panel,
LOW, MID and HIGH correspond to the nameplate
input voltages of a triple voltage welder. Dual voltage
welders use only LOW and HIGH. Single voltage
welders use only HIGH.

EXAMPLE: O n a 208/230/460 volt welder, LOW is

208V, MID is 230V, and HIGH is 460V.

Fuse the input circuit with the recommended super lag
fuses or delay type

1

circuit breakers. Choose an input
and grounding wire size according to local or national
codes, refer to Specification page at the beginning of
this chapter. Using fuses or circuit breakers
smaller than recommended may result in “nuisance”
shut-offs from welder inrush currents even if not
welding at high currents.

Unbalanced AC TIG welding draws higher input
currents than those for stick, DC TIG, or Balanced AC
TIG welding. The welder is designed for these higher
input currents. However, where unbalanced AC TIG
welding above 180 amps is planned, the higher input
currents require larger input wire sizes and fuses.
Refer to Specification page at the beginning of this
chapter.

The Square Wave TIG 255 should be permanently
wired into the power system. No plugs or connectors
are necessary.

OUTPUT CONNECTIONS

WARNING

FIGURE 2 - FRONT PANEL

1. CONTROL AND DISPLAY AREA 5. OPTIONAL WATER SOLENOID

2. POWER SWITCH 6. GAS SOLENOID

3. THERMOSTATIC 7. WORK (LEFT) AND
PROTECTION LIGHT ELECTRODE STUDS

4. POLARITY SWITCH 8. REMOTE RECEPTACLE

TIG TORCH CONNECTION

TIG welding torches come with 12.5 ft (3.8m) and 25 ft
(7.6m) cables. Use the shorter length whenever
possible to minimize possible radio interference
problems. With power source off, connect the torch
cable to the “Electrode” stud on the welder. Connect
a separate work cable to the “Work” stud of the
welder. See Table 1 for recommended work cable
sizes. Both work and electrode cables should be
routed through the cable strain relief holes provided in
the base directly below the welding output terminals.

To avoid receiving a high frequency shock, keep the
TIG torch and cables in good condition.

___________________________________________

See Figure 2 for the location of the work and
electrode terminals, the gas and optional water
solenoids, and the Remote Receptacle.

1

Also called “inverse time” or “thermal/magnetic”
circuit breakers; circuit breakers which have a delay
in tripping action that decreases as the magnitude
of the current increases.

– 11 –

TABLE 1

Cable Sizes for Combined Lengths of Copper

Electrode and Work Cable

Machine Size

255 Amp

40% Duty Cycle #2 (35mm2) #1 (45mm2) 1/0 (55mm2)

Lengths up to

100 ft 100 to 200 ft 200 to 250 ft

TIG torches include the necessary gas and, when
designed for water cooling, water hoses. Connect the
fittings on these hoses to the welder fittings. Any torch
conforming to Compressed Gas Association (CGA)
standards can be connected.

INSTALLATION

The welder fittings have the following threads: Gas
Inlet and Outlet: 5/8”-18 right-hand female; Water inlet
and Outlet: 5/8”-18 left-hand female. The cylinder of
inert shielding gas must be equipped with a pressure
regulator and flow meter. Install a hose between the
flow meter and gas inlet on the welder.

WARNING

Observe the safety precautions necessary for
handling and using compressed gas containers.
Contact your supplier for specific information.

___________________________________________

DO NOT operate a water-cooled torch unless water is

flowing. Water doesn’t flow until solenoid is actuated.
If using a water-cooled torch with a Magnum water

cooler, connect the cooler water outlet to the ‘Water
Valve In” fitting. Connect the TIG torch inlet to the
“Water Valve Out” fitting.

If using a water-cooled torch with a free-running water
supply, install a water line between the welder “Water
Inlet” and the supply. Include a strainer in the water
supply line to prevent dirt particles from obstructing
water flow in the valve and cooling chamber of the
TIG torch. Failure to do so could result in water valve
malfunction and overheating of the water-cooled
torch. Connect the torch water line to the welder
“Water Out” fitting. Use a nonmetallic drain line from
the electrode connection to the drain or water
recirculating pump.

For other conditions, consult the manufacturer’s
instructions for the water cooler or TIG torch being
used.

STICK ELECTRODE CABLE CONNECTION

Turn the Power switch Off. Run the electrode and
work cables through the strain relief holes below the
welding output terminals, and connect the cables to
the proper terminals. This strain relief prevents
damage to the welding output terminals if the cables
are pulled excessively. Select cable size according to
Table 1.

WARNING

Do not connect a TIG torch and stick electrode cable
at the same time. They will both be electrically HOT
whenever the output contactor is energized.

___________________________________________

– 12 –