Lincoln Electric IM467-B User Manual

SQUARE WAVE TIG 355

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Safety Depends on You

Lincoln arc welding and cutting
equipment is designed and
built with safety in mind.
However, your overall safety
can be increased by proper
installation . . . and thoughtful
operation on your part. DO

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.

IM467-B

May, 2003

For use with machines having Code Numbers: 9951, 10056, 10389

9952, 10057, 10390
9953, 10058
9954, 10059
9955, 10060

Cleveland, Ohio 44117-1199 U.S.A. TEL: [phone] FAX: [phone] WEB SITE: www.lincolnelectric.com

OPERATOR’S MANUAL

Copyright © 2003 Lincoln Global Inc.

• World's Leader in Welding and Cutting Products •

• Sales and Service through Subsidiaries and Distributors Worldwide •

i

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

i

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. 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.

___________________________________________________

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.

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

ii

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.

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.

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.

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.

vapors

to

5.e. Also see item 1.b.

Mar ‘95

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.

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.

Mar ‘95

iv

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.

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
zones où l’on pique le laitier.

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

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.

Product _________________________________________________________________________________

Model Number ___________________________________________________________________________

Code Number or Date Code_________________________________________________________________

Serial Number____________________________________________________________________________

Date Purchased___________________________________________________________________________

vv

Where Purchased_________________________________________________________________________

Whenever you request replacement parts or information on this equipment, always supply the information you
have recorded above. The code number is especially important when identifying the correct replacement parts.

On-Line Product Registration

- Register your machine with Lincoln Electric either via fax or over the Internet.

• For faxing: Complete the form on the back of the warranty statement included in the literature packet
accompanying this machine and fax the form per the instructions printed on it.

• For On-Line Registration: Go to our

“Product Registration”. Please complete the form and submit your registration.

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:

WEB SITE at www.lincolnelectric.com. Choose “Quick Links” and then

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.

vi vi

TABLE OF CONTENTS

Page

Safety.................................................................................................................................................i-iv

Installation .............................................................................................................................Section A

Technical Specifications Square Wave TIG 355.........................................................................A-1

Input and Output Specifications ..........................................................................................A-1

Cable and Fuse Sizes...........................................................................................................A-1

Physical Dimensions ............................................................................................................A-1

Safety Precautions......................................................................................................................A-2

Select Suitable Location.............................................................................................................A-2

Stacking................................................................................................................................A-2

Lifting .................................................................................................................................A-2

Tilting .................................................................................................................................A-2

High Frequency Precautions.......................................................................................................A-2

Input Connections.......................................................................................................................A-3

Ground Connection ..............................................................................................................A-3

Input Supply Connections....................................................................................................A-3

Reconnect Procedure .................................................................................................................A-4

Output Connections....................................................................................................................A-6

TIG Torch Connection ..........................................................................................................A-6

Stick Electrode Cable Connection .......................................................................................A-7

Operation...............................................................................................................................Section B

Safety Instructions ...............................................................................................................B-1

General Description ....................................................................................................................B-2

Recommended Processes ...................................................................................................B-2

Operational Features and Controls......................................................................................B-2

Design Features and Advantages ........................................................................................B-2

Welding Capability................................................................................................................B-3

Limitations ............................................................................................................................B-3

Controls and Settings.................................................................................................................B-4

Upper Case Front Controls..................................................................................................B-4

Lower Case Front Controls ................................................................................................B-10

Hand and Foot Amptrol™ Operation.................................................................................B-12

Welding Operation ....................................................................................................................B-14

Initial Start-up.....................................................................................................................B-14

Stick Welding ....................................................................................................................B-14

TIG Welding Guidelines......................................................................................................B-14

TIG Welding Sequence of Operation (2-Step Mode).........................................................B-19

SQUARE WAVE TIG 355

vii vii

TABLE OF CONTENTS

TIG Welding Sequence of Operation (4-Step Mode).........................................................B-19

Overload Protection..................................................................................................................B-20

Auxiliary Power .........................................................................................................................B-20

Accessories...........................................................................................................................Section C

Options/Accessories...................................................................................................................C-1

Maintenance .........................................................................................................................Section D

Safety Precautions......................................................................................................................D-1

Input Filter Capacitor Discharge Procedure...............................................................................D-1

Routine and Periodic Maintenance ............................................................................................D-2

General Component Locations...................................................................................................D-3

Troubleshooting ....................................................................................................................Section E

Wiring Diagram, Dimension Prin tand Equipment Manufacturer’s Certification Form..Section F

Parts Manual .....................................................................................................................P196 Series

SQUARE WAVE TIG 355

A-1 A-1

INSTALLATION

TECHNICAL SPECIFICATIONS - SQUARE WAVE TIG 355

INPUT - SINGLE PHASE ONLY

Input Voltages: 208 230 460 575

Input Currents

@ 350A/34 VDC 110 100 50 40

RATED OUTPUT

Duty Cycle Amps Volts at Rated Amperes

40% Duty Cycle 350 34 v
60% Duty Cycle 300 32 v

100% Duty Cycle 220 29 v

OUTPUT

Maximum Open Continuous

Circuit Voltage Current Range Auxiliary Power

80 Volts Max. 2-400 Amps AC and DC 115 VAC

15 Amps Continuous

RECOMMENDED INPUT WIRE AND FUSE SIZES

For all Stick, DC TIG, and Balanced AC TIG

Welding at 350A/34V/40% Duty Cycle Based

on the 1990 U.S. National Electrical Code

Input (Super Lag) Ampere Copper Wire in Wire in Conduit Copper Wire in Wire in Conduit (Super LAG)

Voltage / or Breaker Rating on Conduit AWG AWG (IEC) Input Conduit AWG AWG (IEC) or Breaker

Frequency Size Nameplate (IEC) Sizes Sizes Amperes (IEC) Sizes Sizes Size

208/60 150 110 4 (25mm2) 6 (16mm2) 148 2 (35mm2) 6 (16mm2) 200

230/60 125 100 6 (16mm2) 6 (16mm2) 134 2 (35mm2) 6 (16mm2) 175

460/60 60 50 8 (10mm2) 10 (6mm2) 67 6 (16mm2) 8 (10mm2)80

575/60 50 40 8 (10mm

Fuse Input Type75°C Copper Ground Type 75°C Copper Ground Fuse

2

Type 75°C Type 75°C

) 10 (6mm2) 54 6 (16mm2) 8 (10mm2)70

For Unbalanced AC TIG Welding Above 230 Amps,

300/32V/60% Duty Cycle, Unbalance Based on the

1990 U.S. National Electrical Code

PHYSICAL DIMENSIONS

Height Width Depth Weight

884 mm 565 mm 660 mm 232 kg

34.84 in. 22.25 in. 26.00 in. 510 lbs.

OPERATING TEMPERATURE RANGE STORAGE TEMPERATURE RANGE

0° to 40°C -50° to 85°C

SQUARE WAVE TIG 355

A-2 A-2

INSTALLATION

Read this entire installation section before you
start installation.

SAFETY PRECAUTIONS

WARNING

ELECTRIC SHOCK can kill.

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

• Insulate yourself from the work
and ground.

• Always wear dry insulating gloves.

Only qualified personnel should install, use, or service
this equipment.

SELECT SUITABLE LOCATION

Place the Square Wave TIG 355 where clean, cooling
air can flow freely in through the side louvers and out
through the rear louvers. Keep dust, dirt, and other
foreign materials that can be drawn into the machine
to a minimum. Failure to observe these precautions
can lead to excessive operating temperatures and
nuisance shut-downs. Read the section, "High
Frequency Interference Protection" before planning
the installation.

TILTING

Place the machine on a secure, level surface or on a
recommended undercarriage. Any surfaces you
place it on other than the ground must be firm, non­skid, and structurally sound.

HIGH FREQUENCY INTERFERENCE
PROTECTION

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.

The Square Wave TIG 355 has been field tested under
recommended installation conditions. It complies with
FCC allowable limits for radiation. For convenience, a
certificate of compliance is packed with the welder. It
can be used to prove FCC RF Energy Radiation Limits
compliance if necessary. (It is the owner's responsi­bility to obtain this certification.) The Square Wave TIG
355 also complies with NEMA standards for high fre­quency stabilized power sources.

Radiated interference can develop in the following four
ways:

1. Direct interference radiated from the welder.

2. Direct interference radiated from the welding leads.

STACKING

Square Wave TIG 355s may be stacked two high.
The bottom machine must be on a stable, hard, level
surface. Be sure that the two pins in the roof of the
bottom machine fit into the holes in the base of the
top machine.

LIFTING

WARNING

CYLINDER MAY EXPLODE if damaged.

• Do not lift the welder with a cylinder attached.

The Square Wave TIG 355 weighs 510 lbs. (232 kg)
without a gas cylinder. Lift the machine by the lift
bail only. Never lift the machine with a cylinder

attached.

SQUARE WAVE TIG 355

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.

A-3 A-3

INSTALLATION

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.

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 con-

tact 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 re-radi­ation, effectively making these members radiating
antennas.

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

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 buidling,
several good earth driven electrical grounds (as in
5 (b) above) around the periphery of the building
are recommended.

FIGURE A.1 – REAR PANEL

2

3

1. WARNING DECAL

2. INPUT POWER ENTRY

3. RECONNECT PANEL COVER

GROUND CONNECTION

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.
Also follow other grounding instructions given in the
section “High Frequency Interference Protection.”

INPUT SUPPLY CONNECTION

Be sure the voltage, phase, and frequency of the input
power is as specified on the welder nameplate.

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 front of the machine.

Welder supply line entry provision is in the case rear
panel with a removable cover over the input connec­tion panel area. See Figure A.1.

SQUARE WAVE TIG 355

WARNING

ELECTRIC SHOCK can kill.

• Have a qualified electrician install
and service this equipment.

• Turn the input power off at the fuse
box before working on this equip­ment.

• Do not touch electrically hot parts.

Have a qualified electrician connect the input power
leads to L1 and L2 of the input contactor in accor­dance with all local codes and national electrical
codes. Use a single phase line or one phase of a two
or three phase line. Refer to the connection diagram
located on the inside of the cover of the Reconnect
Panel. Also see Figure A.2.

A-4 A-4

INSTALLATION

FIGURE A.2 – INPUT SUPPLY CONNECTIONS

WARNING

ELECTRIC SHOCK can kill.

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

• Insulate yourself from the work and ground.

• Always wear dry insulating gloves.

RECONNECT PROCEDURE

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

CAUTION

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

Refer to Figure A.2 for the following procedure.
Welders are shipped connected for the highest input
voltage listed on the rating plate. To change this con­nection for a different input voltage, reconnect both
the power strap (P) and control lead (C) to their
respective terminals 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: On 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
and grounding wire size according to local or national
codes or refer to Tables A.1 and A.2. 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 230 amps is planned, the higher input currents
require larger input wire sizes and fuses. See Table
A.2.

1

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

1

circuit breakers. Choose an input

SQUARE WAVE TIG 355

A-5 A-5

INSTALLATION

The Square Wave TIG 355 should be permanently
wired into the power system. Plugs or connectors are
not recommended.

TABLE A.1

RECOMMENDED INPUT WIRE AND FUSE SIZES

For all Stick, DC TIG, and Balanced AC TIG Welding

Based on the 1990 U.S. National Electrical Code

Input Ampere Type 75°C

Input Rating on Wire in Conduit Grounding Wire Fuse Size

Volt/Freq. Nameplate AWG Copper Cond. AWG Copper Cond. (Super Lag)

208/60 110 4 6 150
230/60 100 6 6 125
460/60 50 8 10 60
200/50 137 4 6 150
220/50 124 4 6 125
440/50 65 8 10 60

(2)

40% Duty Cycle

TABLE A.2

RECOMMENDED INPUT WIRE AND FUSE SIZES

For Unbalanced AC TIG Welding Above 230 AMPS

Based on the 1990 U.S. National Electrical Code

(2)

60% Duty Cycle

Input Amperes

at 300 Amp Type 75°C

Input Unbalanced Wire in Conduit Grounding Wire Fuse Size

Volt/Freq. AC Output AWG Copper Cond. AWG Copper Cond. (Super Lag)

208/60 148 2 6 200
230/60 134 2 6 175
460/60 67 6 8 80
200/50 154 1 6 200
220/50 140 2 6 200
440/50 70 6 8 90

(2)

Article 630 of the 1990 U.S. National Electrical Code allows the rated ampacity of the supply conductors to be determined by multiplying
the nameplate rating by the appropriate multiplier, depending on the duty cycle of the welder.

SQUARE WAVE TIG 355

A-6 A-6

INSTALLATION

OUTPUT CONNECTIONS

WARNING

ELECTRIC SHOCK can kill.

• Keep the electrode holder, TIG
torch and cables insulation in
good condition and in place.

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

• Insulate yourself from work and ground.

• Turn the power off pushbutton on the Square Wave
TIG 355 “off” before connecting or disconnecting
output cables or other equipment.

See Figure A.3 for the location of the work and elec­trode terminals, the gas and optional water solenoids,
and the Remote Receptacle.

TIG TORCH CONNECTION

WARNING

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

FIGURE A.3 – FRONT PANEL

TIG welding torches come with 15 ft (4.6m) 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” terminal on the welder. Connect a sepa­rate work cable to the “Work” terminal of the welder.
See Table A.3 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 ouput terminals.

Connect the TIG torch gas and water fittings to the
welder fittings. any torch with fittings that conform to
Compressed Gas Association (CGA) standards can be
used.

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.

TABLE A.3

CABLE SIZES FOR COMBINED LENGTHS OF COPPER ELECTRODE AND WORK CABLE

1. REMOTE RECEPTACLE

2. WATER AND GAS
SOLENOIDS

3. WORK (LEFT) AND
ELECTRODE TERMINALS

Lengths up to 100 to 200 ft 200 to 250 ft

Machine Size 100 ft (30 m) (30 to 61 m) (61 to 76 m)

350 Amp

40% Duty Cycle #1 (45mm

2

) 1/0 (55mm2) 2/0 (70mm2)

SQUARE WAVE TIG 355

A-7 A-7

INSTALLATION

DO NOT operate a water-cooled torch unless water is
flowing. Water doesn’t flow until the 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 water coolers or torches, 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 A.3

WARNING

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

SQUARE WAVE TIG 355

B-1 B-1

OPERATION

OPERATING INSTRUCTIONS

Read and understand this entire section of operating
instructions before operating the machine.

SAFETY INSTRUCTIONS

WARNING

ELECTRIC SHOCK can kill.

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

• 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 SPARKS can cause
fire or explosion.

• Keep flammable material away.

• Do not weld on containers that have held com­bustibles.

ARC RAYS can burn.

• Wear eye, ear, and body protection.

Observe additional Safety Guidelines detailed in
the beginning of this manual.

SQUARE WAVE TIG 355

B-2 B-2

OPERATION

GENERAL DESCRIPTION

DESIGN FEATURES AND ADVANTAGES

The Square Wave TIG 355 is a constant current, single
range square wave AC/DC TIG (GTAW) arc welding
power source with built-in high frequency stabilization.
It also has stick (SMAW) capability. The Square Wave
TIG 355 gives the operator full control of the welding
current plus the ability to preset weld and start cur­rents. Preflow and postflow timers are included for
shielding gas and cooling water control. Altogether
the many features of the machine allow part or all of a
weld cycle to be preset or "programmed," which sim­plifies the TIG welding process.

The Square Wave TIG 355 includes advanced features
such as Auto-Balance™ 2-Step/4-Step Arc Start
Switch Operation, start controls, crater controls, spot
timer, and status LEDs. Preflow and postflow timers
allow control of shielding gas and cooling water.

RECOMMENDED PROCESSES

The Square Wave TIG 355 is recommended for TIG
(GTAW) and stick (SMAW) welding processes within its
output capability of 2 to 400 amps on both AC and DC
polarity. It is compatible with all Magnum TIG acces­sories as well as many industry standard TIG torches,
hoses, and water coolers. (See the Accessories sec­tion of this manual.)

• Designed to NEMA EW-1 and International IEC-974
Standards.

• Single output range of 2-400 amps covers the
majority of TIG welding applications.

• Solid State Output Contactor: no noise, no parts to
wear.

• Digital Ammeter and Voltmeter for precise readings
from 2-400 amps welding.

• Welding current limit can be preset from 2-400
amps and is displayed on the ammeter when not
welding.

• Auto Balance™ circuitry automatically provides the
proper amount of cleaning and penetration when
AC TIG welding. Manual AC wave balance adjust­ment is also possible.

• 2-Step/4-Step Arc Start switch capability.

• Spot control for 2-Step Arc Start switch mode.

• TIG Pulser with On/Off selection, and Pulses Per
Second adjustment. Background current and duty
cycle are automatically adjusted according to the
peak welding current.

• Crater Fill control for current fade-out at the end of
a weld.

OPERATIONAL FEATURES AND
CONTROLS

The following operational controls are standard on the
Square Wave TIG 355: Local/Remote current control
switch, Stick/TIG mode selection switch, TIG 2­Step/TIG 4-Step mode selection switch, High
Frequency Continuous/Start/Off switch, Peak Current
control, Volts/Amps switch for the digital ammeter
reading, AC Wave Balance control, Afterflow timer for
shielding gas and water flow, Arc Force current control
for stick welding, Preflow timer for shielding gas and
water flow, Spot Time Controls, Start current/time
controls, Pulse controls (pulses per second, back­ground % peak current, pulse % on), and Crater Fill
controls (fade-out, % peak current).

The following additional features are also standard:
Digital ammeter selectable for either volts or amps;
Status Indicator LEDs for gas and water, high frequen­cy, arc established, start, peak, background, crater fill.

• Adjustable preflow time from 0 to 10 seconds.
Preflow time is eliminated if welding restarts during
gas afterflow of previous weld. This avoids unnec­essary delays when making repeated welds.

• Adjustable afterflow time control.

• Locate/Remote current selection.

• Stick/TIG selection.

• Arc Force control of added current when electrode
shorts to the work in stick mode.

• Continuous/Start/Off High Frequency selection.

• DC+/AC/DC- Polarity switch.

• Power Factor Correction for lower input currents
and smaller input wire sizes.

• Remote Receptacle for Amptrol™ or Arc Start
switch.

• Low Voltage Arc Start switch circuit (24 VAC) for
maximum operator safety.

• Gas and optional water valves: Inlet and outlet fit­tings conform to Compressed Gas Association
(CGA) standards.

• Built-In High Frequency Generator.

SQUARE WAVE TIG 355

B-3 B-3

OPERATION

• 115 Volt receptacle with 15 amp circuit breaker.

• Excellent arc starting and stability up through 400
amps.

• High resistance to AC arc rectification.

• No tungsten spitting within current range of elec­trode.

• Compact size, requires only a 22.25 in x 26 in (565
mm 660 mm) footprint.

• Strain relief holes in base for welding cables, gas
and water hoses and control cables.

WELDING CAPABILITY

The Square Wave TIG 355 is NEMA Class II (40) Power
Source rated 350 amps at 34 volts, 40% duty cycle.
The duty cycle is based upon a 10 minute time period.
(For 40% duty cycle, it is 4 minutes on and 6 minutes
off.) The overload capacity is 375 amps at 35 volts,
30% duty cycle.

The “Lincoln Plus” rating of 300 amps at 40 volts pro­vides additional voltage to overcome voltage drops in
long cables when stick welding at high currents.

• Easy access for input connections. Connections
are simple strip and clamp of input wires (no lugs
required).

• Low fan noise at idle.

• Modular construction for easy servicing.

• Unused controls are automatically locked out to
simplify setup. Examples: the AC Wave Balance
control has no effect in DC; the High Frequency and
gas and water valves do not operate in Stick mode;
TIG Pulser is locked out in the Stick mode.

• Recessed panels protect controls, output terminals,
gas and water fittings.

• Large safety margins and protective circuits protect
rectifiers from transient voltages and high currents.

• Line voltage compensated.

• Thermostatically protected.

• Electronic over current protection.

LIMITATIONS

• The Square Wave TIG 355 is not recommended for
arc gouging. The machine's output capacity is too
limited.

• The Square Wave TIG 355 is not recommended for
AC TIG welding with high concentrations of helium
shielding gas. Starting problems and arc rectifica­tion may occur.

• The Square Wave TIG 355 is not recommended for
pipe thawing.

SQUARE WAVE TIG 355

B-4 B-4

OPERATION

CONTROLS AND SETTINGS

UPPER CASE FRONT CONTROLS

Controls on the upper case front control panel are
used for manual TIG and stick welding. Their func­tions are described below. Some controls are active in
both TIG and stick welding, while others are active in
TIG only. Refer to Figure B.1 for control locations.

FIGURE B.1 – UPPER CASE FRONT CONTROLS

1

2

3

4

5

6 7

8

10

9

11

12

1. REMOTE/LOCAL CURRENT CONTROL SWITCH 7. VOLTS/AMPS METER SWITCH 12. PREFLOW TIMER

2. MODE SWITCH (STICK/TIG) 8. AC WAVE BALANCE 13. SPOT CONTROLS

3. 2-STEP/4-STEP SWITCH 9. AUTO-BALANCE™ LED 14. START CONTROLS

4. HIGH FREQUENCY SWITCH 10. AFTERFLOW 15. PULSE CONTROLS

5. DIGITAL VOLTMETER/AMMETER 11. STICK ARC FORCE 16. CRATER FILL CONTROLS

6. PEAK CURRENT CONTROL 17. STATUS INDICATOR LEDs

13

14

SQUARE WAVE TIG 355

15

16

17

B-5 B-5

OPERATION

UPPER CASE FRONT CONTROL PANEL

The upper case front panel controls are used for man­ual TIG and stick welding.

1. CURRENT CONTROL SWITCH

A two-position toggle switch:

LOCAL (PANEL): Current is controlled by the
machine settings; remote Amptrol has no affect
on current.

REMOTE: Current is controlled by a remote
Amptrol up to the current set on the machine.

2. MODE SWITCH

A two-position toggle switch:

STICK: For stick electrode welding (SMAW), this
position makes the Stick Arc Force control active.
This switch locks out high frequency, the gas and
water valves, and the AC Wave Balance control.
The STICK position also locks out the Spot Time,
Start Time and Crater Fill controls. The Pulse con­trols are locked out except when an Arc Start
switch connected to the Remote receptacle is
closed.

TIG: For TIG welding (GTAW), this position locks
out the Stick Arc Force control. It makes all other
controls active. To start and stop the welding
sequence and to get output current, an Amptrol or
Arc Start switch must be used when this switch is
in the TIG position.

3. 2-STEP/4-STEP SWITCH

A two-position toggle switch: (Locked out in the
STICK mode.)

2-STEP: For use with an Arc Start switch or an
Amptrol remote current control. The Arc Start
switch must be held down during the entire weld
cycle. Pressing the Arc Start switch starts the
Preflow cycle, and releasing the switch ends the
weld cycle.

NOTE: If the Crater Fill switch (Item 16) is ON,
welding will continue after the Arc Start switch is
released. (See Crater Fill controls.)

4-STEP: For use with an Arc Start switch only. The
Arc Start switch must be pressed and released to
start the weld cycle. Pressing and releasing the
Arc Start switch a second time ends the weld
cycle. This eliminates the need to continuously
hold down the Arc Start switch during a weld. If
the Preflow timer (Item 12) is being used, the Arc
Start switch must be held down during the Preflow
time. The Arc switch can be released once an arc
is established.

NOTE: If the Crater Fill switch (Item 16) is ON,
welding will continue after the Arc Start switch is
pressed and released the second time. (See
Crater Fill Controls.)

NOTE: If the arc goes out while welding in the 4­Step mode, the machine will try to re-establish an
arc for a period of two seconds. The output con­tactor will remain closed, and the High Frequency,
if in the Start Only or continuous mode, will be
activated. If an arc does not re-establish within
two seconds, the weld cycle is automatically
ended.

4. HIGH FREQUENCY SWITCH

A three-position toggle switch: (Locked out in
STICK mode).

CONTINUOUS: High frequency will come on after
the gas Preflow time and remain on until the weld
is stopped.

START : High Frequency will come on for 1-2 sec­onds after an arc is established, then go off.
(When AC TIG welding, the high frequency will
stay on until after the Start period and come on
again during the Crater Fill period.)

OFF: No high frequency.

5. DIGITAL VOLTMETER/AMMETER

Displays the output voltage of the welder when the
VOLTS/AMPS switch (Item 7) is held in the
“VOLTS” position.

When the VOLTS/AMPS SWITCH IS IN THE
“AMPS” position, this display functions as an
ammeter.

When you are not welding, the ammeter displays
the value preset by the Peak Current control.

When you are not welding and the Start Current
Display pushbutton is pressed, the ammeter will
display the preset Start (Item 14). (See Start
Controls)

NOTE: The ammeter display is an indicator of the
preset current. Actual welding current will be
slightly different.

While you are welding, the ammeter displays the
actual welding current. The ammeter is accurate
within ±3% of its reading or ±2 amps, whichever is
greatest. The ammeter displays RMS current.
(RMS current is the actual “heating value” of the
arc.) NOTE: Some types of ammeters will not
accurately read true RMS currents, particularly
when AC TIG welding aluminum. AC only amme­ters may read as much as 40% low when measur­ing AC TIG welding currents.

SQUARE WAVE TIG 355

B-6 B-6

OPERATION

6. PEAK CURRENT CONTROL

Presets the maximum welding current the
machine will produce, from 2 through 400 amps.
The preset current is displayed on the digital
ammeter when you are not welding.

NOTE: The ammeter display is an indicator of the
preset current. Actual welding current will be
slightly different.

If you use an Amptrol, it will control the current
from 2 amps up to the current preset by the Peak
Current control. See the section, “Hand and Foot
Amptrol Operation” for proper use of hand and
foot Amptrols.

If pulsing, the peak current is the current set and
controlled by the Peak Current control (Item 6) and
the Amptrol.

7. VOLTS/AMPS SWITCH

A two-position, spring-loaded toggle switch for
selecting either arc voltage or welding current/pre­set current to be displayed on the digital meter.

To read the arc voltage, you must hold the switch
in the “Volts” position. This spring-loaded switch
always returns to the “AMPS” position when
released.

8. AC WAVE BALANCE

This control is active only in AC TIG mode. It con­trols the amounts of positive and negative current
in the AC output. It has no effect on stick or DC
TIG welding.

AUTO BALANCE
ic adjustment of the AC wave balance, and it is the
preferred balance setting for most welding condi­tions. This setting gives the ideal amount of clean­ing and penetration, based on the welding current
output. When the control is set to the Auto
Balance position, the Auto Balance LED (Item 9)
will light. This feature operates only in the AC TIG
mode.

For those procedures when manual adjustment of
the Wave Balance control is necessary, use the
following as a guide:

™

: This setting provides automat-

.

CAUTION

Use only the amount of “cleaning” required. Greater
amounts of positive current will heat the tungsten
more and possibly cause it to melt or “spit.” Also, the
arc is usually more flared and less stable with more
positive “cleaning” current.

PENETRATION (Above “3” on the dial): Provides
more negative current than positive current. The
“cleaning” effect will be reduced, but the arc plas­ma will be more concentrated and more easily
directed to where the heat is needed. The
reduced amount of positive current allows the
tungsten to run cooler at a given current than
when set balanced.

In general, use just enough “cleaning” to remove
oxides and to give good wetting of the puddle.

™

9. AUTO BALANCE

Illuminates only when the Auto Balance function is
active. The welder must be in the AC TIG mode,
with the AC Wave Balance control fully clockwise.

10. AFTERFLOW

This control adjusts the amount of time the gas
and water valves stay open after the end of a weld.
Minimum time is approximately 5 seconds; maxi­mum is approximately 55 seconds. Use enough
Afterflow time to protect the hot tungsten with gas
shielding until it cools. Too short of a time will
cause the tungsten to oxidize and become conta­minated. When in doubt, set a longer time, then
reduce it to a time that still gives good protection.

PREFLOW

All machines have an adjustable Preflow time.

If a new weld is started during the Afterflow time of
a previous weld, the Preflow time is bypassed,
since gas shielding is already present. This allows
new welds to start immediately, with no preflow
delay.

11. ARC FORCE

LED

BALANCED: The amounts of positive and negative
are the same.

CLEANING (Below “3” on the dial): Provides more
positive current than negative current. Since the
positive current produces the “cleaning” or oxide
removal on aluminum, this setting is used for
heavily oxidized aluminum.

SQUARE WAVE TIG 355

This control is active only in Stick mode. It con­trols the amount of current added to the welding
current when the electrode shorts to the work.

At Minimum, no extra short circuit current is
added. The arc will be softer and will have less
spatter but may be more prone to sticking.

B-7 B-7

OPERATION

At Maximum, the arc will be more forceful and less
prone to sticking but will produce more spatter.

12. PREFLOW

This control adjusts the amount of time the gas
and water valves are open before the arc starts. It
is adjustable from 0 to 10 seconds.

Press and hold in this pushbutton to display the
Start Current preset by the Start Current control.
(The Volts/Amps switch (Item 7) must be in the
“AMPS” position to read preset current.)

Start Current Control

Locked out if the Start switch is off.

The Preflow time occurs only if the valves were
closed (no gas flow) when the Arc Start switch or
Amptrol was pressed. If a new weld is started
while the gas valve is still on during the Afterflow
time of a previous weld, the Preflow time is
bypassed since gas shielding is already present.
This allows new welds to start immediately with no
preflow delay.

Note that since the arc cannot start during the
Preflow time, a long Preflow setting can cause
complaints about arc starting. In general, a
Preflow time of 0.5 seconds is satisfactory for
most applications.

13. SPOT CONTROLS

Spot Switch — A two-position toggle switch:

Recommended for use in the 2-step Arc Start
Switch mode only.

ON: Spot Time control is active. Once the arc is
established, the Spot time begins. At the end of
the Spot time (or if the Arc Start switch/Amptrol is
released sooner), the arc stops. (If Crater Fill [Item
16] is on, downslope begins.)

OFF: Locks out the Spot Time control.

Spot Time Control: Not active if the Spot switch
is off. Adjusts weld time from 0.1 to 5 seconds.
Weld time is the time from when the arc is fully
established until the arc is turned off (or when
Crater Fill downslope is started). The Arc Start
switch or Amptrol must be held down during the
Spot time; if it is released before the end of the
Spot time, the arc will be turned off (or Crater Fill
started).

14. START CONTROLS

Start Switch — A two-position toggle switch:

ON: Start Current control is active. At the begin­ning of the weld, current will be the value preset by
the Start Current control. Th position of the
Amptrol has no effect on this current.

OFF: Locks out Start Current and Time controls.

Presets the current that will be provided at the
start of the weld. The current can be preset from
2 to 400 amps. The position of the amptrol has no
effect on the initial current. The present Start
Current is displayed on the Ammeter when the
pushbutton is pressed before welding.

A “hot” start is used to quickly heat the tungsten
and work, usually on DC TIG welding. Set the
Start Current higher than what the welding current
will be. After the time is set on the Start Time con­trol, the current will step down to the current set
and controlled by the Peak Current control (Item 6)
and the Amptrol.

A “soft” start is used to preheat the tungsten and
work, usually on AC TIG welding. Set the Start
Current lower than what the welding current will
be. The arc will establish at the Start Current and
then ramp up to the current set and controlled by
the Peak Current control (Item 6) and the Amptrol.
The time to get up to welding current is set by the
Start Time control. During the ramp up, the
Amptrol will affect the current that the ramp is
going toward and therefore the rate at which the
current increases.

Start Time Control

Locked out if the Start switch is off. Adjusts the
Start Time from approximately 0.1 to 10 seconds.

15. PULSE CONTROLS

Pulse Switch — A two-position toggle switch:

ON: Pulsing will begin as soon as an arc is estab­lished and will continue until the weld is complet­ed. If you are using Start Controls, pulsing begins
after the Start Current. If you are using Crater Fill,
pulsing will continue during the downslope period.

OFF: Locks out Pulse controls.

Pulses per Second Control — Controls the num­ber of pulses per second from approximately 0.1
to 10 pps. 0.1 pulses per second is slow pulsing
(one pulse every 10 seconds); 10 pulses per sec­ond is fast pulsing.

Start Current Display Pushbutton

Background % Peak Current Control —
Controls the background (low pulse) current from
zero to 100% of the peak current set and con­trolled by the Peak Current control (Item 6) and the
Amptrol.

SQUARE WAVE TIG 355

B-8 B-8

OPERATION

Example: The Peak Current control is preset at 50
amps and the Amptrol is partially down, giving a
peak current of 30 amps. If the Background
Current control is set at 50%, the Background (low
pulse) current will be 15 amps.

The Amptrol raises and lowers the Peak current.
Since Background current is always a percentage
of Peak current, the Amptrol also raises and low­ers the Background current.

Pulse % On — Controls the percentage of the
pulse cycle that is at the Peak current.

Example: You are pulsing at 1 Pulse per second
with a 30% Pulse % On setting. The welding cur­rent would be at the Peak current for 0.3 seconds
and at the Background current for the remainder
of the cycle, 0.7 seconds.

16. CRATER FILL CONTROLS

Use the Crater Fill controls to automatically control
current fade-out at the end of a weld. LOCAL cur­rent control (Item 1) MUST be used when Crater
Fill is used.

Crater Fill Switch — A two-position toggle
switch.

ON: Crater Fill Fade-out will begin when the Arc
Start Switch or Amptrol is released (2-Step mode)
or pressed and released a second time (4-Step
mode). If used with Spot Time (item 13), Crater Fill
begins at the end of the Spot Time. The current
control (item 1) switch must be in LOCAL when
using Crater Fill.

OFF: Locks out Crater Fill controls.

Fade-out Control — Controls how slowly the cur­rent fades out. The FAST setting will cause current
to ramp down from the welding current toward 2
amps in approximately 1/2 second; the SLOW set­ting, in approximately 20 seconds. The time for
downslope to the Crater Fill Current level depends
on the difference between the weld current and
the Crater Fill Current.

Crater Fill % Peak Current Control — Controls
the final Crater Fill current from zero to 100% of
the weld current preset on the Peak Current con­trol.

Example: WIth a Crater Fill % Current setting of
20% and a weld current preset at 100 amps, the
current will fade from 100 amps to 20 amps and
then dwell at 20 amps for about 1-1/2 seconds
before the arc goes out.

The final Crater Fill current dwell time is approxi­mately 1-1/2 seconds, regardless of Crater Fill
control settings.

17. STATUS INDICATOR LEDs — Seven Light

Emitting Diodes (LEDs) which light when their
function is active.

• GAS & WATER LED is on when the solenoid
valves are open, from the beginning of Preflow
to the end of Afterflow.

• HIGH FREQUENCY LED is on when the high
frequency circuit is on.

FIGURE B.2 – STATUS INDICATOR LIGHT SEQUENCE

SQUARE WAVE TIG 355

SQUARE WAVE TIG 355

B-9 B-9

OPERATION

• ARC ESTABLISHED LED goes on when the arc
is fully established and goes out if the arc goes
out.

• START LED is on from the time the arc is estab­lished until current begins to go up (soft start) or
down (hot start). Note that the Start LED is off
during upslope if a soft start is used.

• PEAK LED goes on after the Start period. If the
Pulse switch is on, the Peak LED goes off dur­ing the Background periods. The Peak LED and
Background LED will alternate when pulsing.

• BACKGROUND LED is on during the
Background (low pulse) period of pulsing.

• CRATER FILL LED is on during the Fade-Out
downslope and final current periods.

NOTE: An LED will light in response to the control cir­cuit command, even if other components do not work.
For example, if the gas supply is turned off or the gas
solenoid valve malfunctions or the fuse is blown, the
gas will not flow even though the Gas and Water LED
lights up. Another example is the High Frequency LED
which can light, yet there will not be high frequency
due to a blown fuse or defective high frequency circuit
or spark gaps set too large.

The Status Indicator LEDs are useful for understanding
which functions are active during a weld sequence
and for how long. They are useful for setting times of
the controls on the Function Panel. See Figure B.2.

The Status Indicator LED circuit board includes a
receptacle for plugging in the circuit board included
with the Optional Interface Kit.

SQUARE WAVE TIG 355

B-10 B-10

OPERATION

LOWER CASE FRONT CONTROLS

Refer to Figure B.3 for the location of the following controls.

FIGURE B.3 – LOWER CASE FRONTCONTROLS

4

5

3

2

1

9

6

8

7

SQUARE WAVE TIG 355

B-11 B-11

OPERATION

1. POWER ON/OFF — A momentary start/stop
pushbutton, which controls the input contactor. If
the input power supply goes off or if the thermo­stat in the welder trips, the start pushbutton must
be pressed to restart the welder.

2. PILOT LIGHT — Indicates when the input contac-
tor is energized (power is on).

CAUTION

Do not switch polarity under load.

3. POLARITY SWITCH — Selects DC-/AC/DC+

4. FUSE F1 — 0.5 amp control circuit fuse protects
the control transformer from overloads. Input
overvoltage protection circuitry will blow this fuse
to protect electronic components if the input volt­age to the welder is too high (more than 40% over
rated voltage). If this fuse blows, the digital meters
will not light and the input contactor will not latch
when the Power On/Off Start pushbutton is
pressed and released.

5. FUSE F2 — 1.5 amp gas, water, and high fre-
quency fuse protects the circuitry that drives the
gas and water valves and the high frequency sup­ply transformer. If this fuse blows, the valves and
high frequency will not work. However, the LEDs
for Gas and Water and High Frequency will still
light.

6. REMOTE RECEPTACLE — A six-pin circular con-
nector for an Arc Start switch or an Amptrol
remote current control.

7. 115 VOLT RECEPTACLE AND CIRCUIT BREAK-
ER — A duplex 15 amp grounded NEMA 5-15R
receptacle and 15 amp circuit breaker. Fifteen
amps of 115 volt AC power is available continu­ously whenever the power is on. The circuit
breaker button will pop out if it trips. Reset by
pushing it in after the circuit breaker cools and the
overload has been removed.

8. HIGH FREQUENCY INTENSITY CONTROL AND
SPARK GAP — This control changes the high fre­quency intensity. Use the lowest intensity which
still gives good arc starting to minimize Radio
Frequency Interference (RFI). The spark gap is set
at the factory to the normal setting marked on the
cover plate. Instructions for larger or smaller gap
settings are also on the cover plate.

9. GAS AND OPTIONAL WATER VALVES —
Solenoid valves that open at the beginning of the
Preflow time and close at the end of the Afterflow
time.

The gas valve inlet and outlet are standard 5/18-18
right-hand female fittings. The water valve inlet
and outlet are standard 5/8-18 left-hand female fit­tings. The fittings conform to CGA (Compressed
Gas Association) standards. Use a water line
strainer to prevent particles from jamming the
water valve.

SQUARE WAVE TIG 355

B-12 B-12

OPERATION

HAND AND FOOT AMPTROL OPERATION

Both the Hand and Foot Amptrol (optional kits K870 or
K963) work in a similar manner. They are meant to be
used for remote current control when Remote Current
control is selected. The TIG 2-Step mode must be
selected when using an Amptrol for remote current
control. As explained below, Amptrols can also be
used as arc start switches if Local Current control is
selected.

For simplicity, the following explanation will refer only
to “Amptrols,” meaning both Foot and Hand models.
The term “minimum” refers to a Foot pedal in the “up”
position, as it would be with no foot pressure, or a
Hand Amptrol in the relaxed position, with no thumb
pressure. “Maximum” refers to a fully depressed Foot
Amptrol, or a fully extended Hand Amptrol.

The Amptrol is capable of controlling the output cur­rent from 2 amps to whatever current is preset on the
ammeter. For example, if the ammeter is preset for
200 amps and the Current Control switch is in the
Remote position, the Amptrol, when depressed just
past its minimum position, will cause the Square Wave
TIG 355 to weld at 2 amps. At the Amptrol’s maximum
position, the output would be near 200 amps. See
Figure B.4.

CAUTION

Since the full output of the current setting is available
when the Amptrol is fully depressed, care must be
taken not to set a current which will exceed the current
carrying capacity of the tungsten. When in doubt, use
a lower current setting first, then increase.

A similar situation occurs when the Start controls are
used. For example, a 3/32” (2.4 mm) tungsten is again
used for welding DC- up to 200 amps (preset on the
ammeter). A Start current of 50 amps is set on the
Start Level control. When you depress the Amptrol,
the start circuitry sets the output current to 50 amps.
If the Amptrol is kept near the minimum position, at the
end of the start period the output current will drop to 2
amps, causing the arc to go out in most cases.
Depress the Amptrol at least 1/4 of the way down, or
to around 70 amps, so that the tungsten remains lit
when the start period ends.

The same holds true for a “hot” start, or one in which
the Start current is set to a current higher than the cur­rent preset on the ammeter. Again, at the end of the
start period, the Amptrol must be depressed far
enough so that the machine output will be high
enough to keep the arc lit.

The best technique when using the start controls and
an Amptrol is to press the Amptrol to maximum at the
beginning of the weld, wait until the end of the start
period, and then back off on the amptrol only if the
current is too high.

If the Current Control switch is set to the Local posi­tion, an Amptrol can be used as an arc start switch.
Depressing the amptrol just past minimum will cause
the Amptrol’s built-in arc start switch to close, and
backing off completely causes the built-in start switch
to open. The Amptrol will have no effect on the weld­ing current when used as an arc start switch. See
Figure B.5.

It is important to note that, for many applications, the
tungsten will not start an arc at only 2 amps. To start
an arc reliably, it is important to depress the Amptrol
far enough so that the machine output current is near
the tungsten operating range. (See Table B.2 for rec­ommended tungsten currents.) In the example above,
a 3/32” (2.4 mm) tungsten may be used on DC- to
weld near 200 amps. To start the weld, the operator
may have to depress the Amptrol approximately 1/4 of
the way down, or to nearly 70 amps, in order to start
the arc. Merely depressing the Amptrol to its 2 amp
minimum position will not start the arc.

SQUARE WAVE TIG 355

B-13 B-13

OPERATION

FIGURE B.4 – AMPTROLS USED WITH CURRENT CONTROL IN THE LOCAL POSITION

FIGURE B.5 – AMPTROLS USED WITH CURRENT CONTROL IN REMOTE POSITION

SQUARE WAVE TIG 355

B-14 B-14

OPERATION

WELDING OPERATION

INITIAL START-UP

Be sure the Square Wave TIG 355 has been installed
correctly with respect to location, high frequency pro­tection, input power, and output connections.

If you are TIG welding, connect a K870 or K963
Amptrol or a K814 Arc Start switch to the Remote
Receptacle. Check that the gas supply is on. Check
for the correct type and size of tungsten electrode, gas
cone size and torch size. If you are using a water
cooled torch, check that the water supply is on.

Press the Start (green) Power pushbutton. The input
contactor will pull in, the pilot light will come on, the
meter displays will light up, and the fans will start. In
TIG mode, the gas and water valves will open for one
Afterflow period to purge the lines. The ammeter will
display the preset current (if there is no load on the
welder output terminals). The voltmeter will read zero
in TIG mode, or from 60 to 70 in STICK mode.

Select the Electrode Polarity needed (DC-/AC/DC+) .

Set the controls by going from left to right across the
top row and then the bottom row, choosing the correct
setting for each. Note that the bottom row of controls
includes on/off switches to easily lock out the controls
within blocks (Spot, Start, Pulse, or Crater Fill) without
changing the settings. Also, note that some of the
controls are automatically locked out internally if they
do not apply in STICK mode or do not apply in TIG
mode. This reduces the number of controls which
must be set. See Table B.1 for examples of the effects
of the Function controls on TIG welding.

STICK WELDING

1. Remove the Amptrol or Arc Start switch from the
Remote Receptacle.

2. Turn the welder on. The pilot light on the front
panel indicates when the power is on.

3. Select LOCAL current control;

Select STICK mode. (High Frequency switch has
no effect in STICK mode.)

4. Preset the current with the Current control and the
Ammeter.

5. Set the desired Arc Force. (See CONTROLS AND
SETTINGS, item 11, “Arc Force.”) (The Wave
Balance and Afterflow controls have no effect in
STICK mode.)

6. Turn the Start switch OFF, or set the START con­trols for a hot start if needed. (See CONTROLS
AND SETTINGS, item 14, “Start Controls.”)

7. Strike an arc and weld. (There will be a buzzing
sound from the arc if you are AC welding, due to
the faster rate of current reversal of the Square
Wave.

TIG WELDING GUIDELINES

Recommended tungsten electrode sizes, stickouts,
currents, cup or nozzle sizes and gas flow are shown
in Table B.2. SINCE TIG APPLICATIONS CAN VARY,
THIS TABLE IS INTENDED AS A GUIDE ONLY.

Aluminum Welding: Set the Electrode Polarity switch
to AC, the High Frequency switch to CONTINUOUS,
and the Mode switch to TIG. Make all other control
settings to suit the size tungsten and current. In gen­eral, pure or zirconiated tungsten electrode is best for
aluminum and should have a “balled” end not exceed­ing the diameter of the tungsten. A buzzing sound will
occur in the arc when AC TIG welding aluminum. We
recommend that you set the AC Wave Balance control
to the Auto Balance position. For more information
see CONTROLS AND SETTINGS, item 8, “AC Wave
Balance.”

Stainless or Mild Steel Welding: Set the Electrode
Polarity switch to DC-, the High Frequency switch to
START, and the Mode switch to TIG. In general, 1% or
2% thoriated tungsten electrode is best for stainless or
mild steel and should have the end ground to a point.
If there is difficulty starting the arc, the tunsten may be
contaminated, or it may be too large to get up to oper­ating temperature.

Note: Starting difficulties may often be due to not

pressing the Amptrol far enough. When the
Amptrol is just “cracked,” the minimum current
(2 amps) is produced. Pressing the Amptrol
more at the start of the weld will often solve
starting problems.

SQUARE WAVE TIG 355

B-15 B-15

OPERATION

TABLE B.1

SPECIFIC EFFECTS OF CONTROLS

(illustrated in the 2-Step Mode for clarity)

EFFECT OF CONTROLS ON TIG WELDING

CLOSE ARC

START SWITCH

WELD BEGINS

PREFLOW

OPEN ARC

START SWITCH

PRESET
CURRENT

AFTERFLOW

LOCAL CURRENT CONTROL
ALL LOWER PANEL
SWITCHES OFF

REMOTE AMPTROL CONTROLS

START TIME

REMOTE AMPTROL CONTROLS

FROM 2 AMPS UP TO

PRESET CURRENT

START CURRENT

FROM 2 AMPS UP TO

PRESET CURRENT

PRESET
CURRENT

PRESET
CURRENT

REMOTE CURRENT CONTROL
ALL LOWER PANEL
SWITCHES OFF

LOCAL OR REMOTE CURRENT CONTROL
START SWITCH ON
START CURRENT SET HIGHER THAN

PRESET CURRENT (HOT START)
START TIME: VARIABLE
ALL OTHER PANEL SWITCHES OFF

HOT START

SQUARE WAVE TIG 355

B-16 B-16

OPERATION

EFFECT OF CONTROLS ON TIG WELDING

CLOSE ARC

START SWITCH

MIN

TIME

START

START

CURRENT

WELD BEGINS

MAX START

TIME

REMOTE AMPTROL CONTROLS

FROM 2 AMPS UP TO

PRESET CURRENT

OPEN ARC

START SWITCH

PRESET
CURRENT

LOCAL OR REMOTE CURRENT CONTROL
START SWITCH ON
START CURRENT SET LOWER THAN

PRESET CURRENT (SOFT START)
START TIME: VARIABLE
ALL OTHER PANEL SWITCHES OFF

PRESET

CURRENT

FAST FADE-OUT

START
CURRENT

-3 SEC.
CRATER FILL TIME

PRESET
CURRENT

CRATER FILL
% CURRENT

OPEN

ARC

START

SWITCH

PRESET
CURRENT
(PEAK)

BACKGROUND
% CURRENT

SLOW
FADE-OUT

LOCAL CURRENT CONTROL
CRATER FILL SWITCH ON
CRATER FILL % CURRENT VARIABLE
FADE-OUT VARIABLE

ALL OTHER LOWER PANEL SWITCHES

CRATER FILL

% CURRENT

OFF

LOCAL CURRENT CONTROL
START SWITCH ON

(SOFT START SHOWN; MAY HAVE HOT
START)
CRATER FILL SWITCH ON
ALL OTHER PANEL SWITCHES OFF

LOCAL OR REMOTE CURRENT CONTROL
PULSE SWITCH ON

PULSES PER SECOND
BACKGROUND % DUTY CYCLE
PULSE % ON
ALL OTHER LOWER PANEL SWITCHES

OFF

START & CRATER FILL

PULSE SOFT STARTCRATER FILL

REMOTE AMPTROL CONTROLS

FROM 2 AMPS UP TO

PRESET CURRENT

SQUARE WAVE TIG 355

B-17 B-17

OPERATION

EFFECT OF CONTROLS ON TIG WELDING

CLOSE ARC

START SWITCH

WELD BEGINS

START TIME
START CURRENT

BACKGROUND
% CURRENT

OPEN ARC

START SWITCH

PRESET
CURRENT

LOCAL CURRENT CONTROL
START SWITCH ON

(SHORT HOT START SHOWN)

PULSE SWITCH ON
CRATER FILL SWITCH ON

CRATER FILL

% CURRENT

(SLOW FADE-OUT SHOWN)
SPOT SWITCH OFF

START & PULSE & CRATER FILLSPOT

LOCAL OR REMOTE
SPOT SWITCH ON

ALL OTHER LOWER PANEL SWITCHES

OFF

SPOT TIME

CLOSE ARC

START SWITCH

SPOT TIME

CLOSE ARC

START SWITCH

PRESET
CURRENT

(SPOT TIME IS CUT SHORT IF ARC
START SWITCH IS OPENED BEFORE
END OF SPOT TIME)

OPEN ARC

START SWITCH

PREFLOW

REMOTE AMPTROL CONTROLS CURRENT

FROM 2 AMPS UP TO PRESET CURRENT

AFTER SPOT TIME

THE SPOT TIMER CAN BE USED TO TIME A PROGRAMMED SEQUENCE OF START AND/OR
PULSE UP TO 5 SECONDS LONG, OPTIONALLY FOLLOWED BY CRATER FILL. IF CRATER FILL
IS USED, FADE-OUT BEGINS AT THE END OF THE SPOT TIME.

SQUARE WAVE TIG 355

SPOT & START PULSE & CRATER FILL

B-18 B-18

OPERATION

TABLE B.2

TYPICAL CURRENT RANGES

(1)

FOR TUNGSTEN ELECTRODES

(2)

DCEN (-) DCEP (+)

AC

Unbalanced Wave Balanced Wave

Approximate Argon

Gas Flow Rate

C.F.H. (l/min)

Tungsten 1%, 2% 1%, 2%

Electrode 1%, 2% 1%, 2% Thoriated Thoriated TIG Torch

Diameter Thoriated Thoriated Pure Tungsten Pure Tungsten Stainless Nozzle

in. (mm) Tungsten Tungsten Tungsten Zirconated Tungsten Zirconiated Aluminum Steel Size

.010 (.25) 2-15

0.020 (.50) 5-20

0.040 (1.0) 15-80

(3)

(3)

3)

(

2-15 2-15 2-15 — 3-8 (2-4) 3-8 (2-4) 4,5,6
5-15 5-20 10-20 5-20 5-10 (3-5) 5-10 (3-5)

10-60 15-80 20-30 20-60 5-10 (3-5) 5-10 (3-5)

(4), (5)

1/16 (1.6) 70-150 10-20 50-100 70-150 30-80 60-120 5-10 (3-5) 9-13 (4-6) 5,6

3/32 (2.4) 150-250 15-30 100-160 140-235 60-130 100-180 13-17 (6-8) 11-15 (5-7) 6,7,8
1/8 (3.2) 250-400 25-40 150-210 225-325 100-180 160-250 15-23 (7-11) 11-15 (5-7)

5/32 (4.0) 400-500 40-55 200-275 300-400 100-240 200-320 21-25 (10-12) 13-17 (6-8) 8,10
3/16 (4.8) 500-750 55-80 250-350 400-500 190-300 290-390 23-27 (11-13) 18-22 (8-10)
1/4 (6.4) 750-1000 80-125 325-450 500-630 250-400 340-525 28-32 (13-15) 23-27 (11-13)

(1) When used with argon gas. The current ranges shown must be reduced when using argon/helium or pure helium shielding gases.
(2) Tungsten electrodes are classified as follows by the American Welding Society (AWS):

Pure .................................EWP

1% Thoriated ..................EWTh-1

2% Thoriated ..................EWTh-2

Though not yet recognized by the AWS, Ceriated Tungsten is now widely accepted as a substitute for 2% Thoriated Tungsten in AC and DC applications.
(3) DCEP is not commonly used in these sizes.
(4) TIG torch nozzle “sizes” are in multiples of 1/16ths of an inch:

# 4 = 1/4 in. (6mm)
# 5 = 5/16 in. (8mm)
# 6 = 3/8 in. (10mm)
# 7 = 7/16 in. (11mm)
#8 = 1/2 in. (12.5mm)
#10 = 5/8 in. (16mm)

(5) TIG torch nozzles are typically made from alumina ceramic. Special applications may require lava nozzles, which are less prone to breakage, but cannot withstand high

temperatures and high duty cycles. Currents above 350 amps require metal nozzles on water cooled torches.

SQUARE WAVE TIG 355

B-19 B-19

OPERATION

TIG WELDING SEQUENCE OF
OPERATION (2-STEP MODE)

hose and torch. After a time determined by the
Preflow control setting, the high frequency
becomes available to strike the arc.

WARNING

Do not leave stick electrode welding cable connected.
It will be electrically “hot” when TIG welding.

1. Connect an Amptrol or Arc Start switch to the
Remote Receptacle.

2. Turn the welder, water supply (if equipped) and
gas supply on. The pilot light on the front panel
indicates when the power is on.

3. Select REMOTE or LOCAL current control
(REMOTE requires an Amptrol).

Select TIG mode.
Select CONTINUOUS or START high frequency.
Select AC or DC- electrode polarity. See Table B.3
for recommended polarity settings.

TABLE B.3

RECOMMENDED SETTINGS FOR TIG WELDING

Electrode High Frequency

Type of Welding Polarity Switch

Stainless Steel DC- Start

Aluminum and

Magnesium AC Continuous

Other Metals DC- Start

11. Hold the Arc Start Switch down or operate the
Amptrol until the weld is completed. Release the
Arc Start switch or the Amptrol to stop the arc.
When the Afterflow timer completes the cycle, the
gas and water valves close. To make another
weld, repeat steps 10 and 11.

TIG WELDING SEQUENCE OF
OPERATION (4-STEP MODE)

WARNING

Do not leave stick electrode welding cable connected.
It will be electrically “hot” when TIG welding.

1. Connect an Arc Start switch to the Remote
Receptacle.

2. Turn the welder, water supply (if so equipped) and
gas supply on. The pilot light on the front panel
indicates when the power is on.

3. Select LOCAL current control. Select TIG mode.
Select CONTINUOUS or START high frequency.
Select AC or DC- electrode polarity (See Table
B.3 for recommended polarity settings).

4. Preset the maximum current with the Peak
Current control and the Ammeter.

5. (Arc Force Control has no effect in TIG mode.)

4. Preset the maximum current with the Current con­trol and the Ammeter.

5. (Arc Force control has no effect in TIG mode.)

6. If in AC, set AC Wave Balance control. (See CON­TROLS AND SETTINGS, item 8, “AC Wave
Balance.” This control has no effect in DC.)

7. Set Afterflow time.

8. Set Function Panel controls as needed. (See
CONTROLS AND SETTINGS.)

9. Press the Arc Start switch or Amptrol and set the
gas flowmeter. The welder is now ready for weld­ing.

10. Position the tungsten electrode at the start of the
weld at a 65° to 75° angle with the horizontal so
that the electrode is approximately 1/8” (3.2 mm)
above the workpiece. Press the Arc Start switch
or operate the Amptrol. This opens the gas and
water valves to automatically purge air from the

SQUARE WAVE TIG 355

6. If in AC, set AC Wave Balance control. (See CON­TROLS AND SETTINGS, item 8, “AC Wave
Balance. This control has no effect in DC.)

7. Set Afterflow time.

8. Set Function Panel controls as needed. (See
CONTROLS AND SETTINGS, “Lower Case Front
Controls”)

9. Press the Arc Start switch and set the gas
flowmeter. The welder is now ready for welding.

10. Position the tungsten electrode at the start of the
weld at a 65° to 75° angle with the horizontal so
that the electrode is approximately 1/8” (4 mm)
above the workpiece. Press the Arc Start switch.
This opens the gas and water valves to automati­cally purge air from the hose and torch. After a
time determined by the Preflow control setting,
the high frequency becomes available to strike the
arc.

B-20 B-20

OPERATION

11. Hold the Arc Start switch down until an arc is
established. At this point, the Arc Start Switch
can be released, and the weld will continue.
Press and release the Arc Start switch a second
time to stop the arc. When the Afterflow timer
completes the cycle, the gas and water valves
close. To make another weld, repeat steps 10
and 11.

Note: Starting difficulties may often be due to not
pressing the Amptrol far enough. When the Amptrol is
just “cracked,” the minimum current (2 amps) is pro­duced. Pressing the Amptrol more at the start of the
weld will often solve starting problems.

OVERLOAD PROTECTION

The Square Wave TIG 355 has thermostatic protection
from overloads, loss of cooling, and high ambient tem­peratures. When the welder is subjected to an over­load or loss of cooling, a thermostat will open.

If the secondary thermostat opens, the effect will be
the same as pushing the Stop power pushbutton: the
power will go off, the pilot light and meters will go out,
and the fans will stop. Pressing the Start power push­button after the thermostat cools and resets will restart
the welder.

AUXILIARY POWER

ALL MACHINES

The Square Wave TIG 355 provides 15 amps of 115
volt AC power at a standard NEMA 5-15R receptacle,
located on the lower case back of the machine. This
circuit is protected from shorts and overloading by a
15 amp circuit breaker, located next to the receptacle.
The auxiliary circuit is intended for running water cool­ers and small power tools, whose current draw is with­in the 15 amp rating.

CAUTION

Note that some types of equipment, especially pumps
and motors, have starting currents significantly higher
than their running currents. These higher starting cur­rents may cause the circuit breaker to open. If this sit­uation occurs, the user should avoid using the Square
Wave TIG 355 auxiliary for that equipment.

If the primary thermostat opens, the power will stay on
(pilot light and meters on and fans running), but no
more than 5 amps DC output current will be available.
This allows the fans to cool the machine. Depending
on the amount of welder overload, the thermostat
should reset within five minutes with the fan motors
running. When the primary thermostat cools and
resets, normal output current will be available.

SQUARE WAVE TIG 355

FEB97

C-1 C-1

ACCESSORIES

OPTIONS/ACCESSORIES

The following options/accessories are available for
your Square Wave TIG 355 from your local Lincoln
Electric Distributor.

Undercarriage (K841) – Includes a platform, wheels,
and brackets for supporting the welder and two gas
cylinders.

Pump Mounting Platform (K827) – Mounts on top of
the welder to provide a mounting surface suitable for
water recirculating pumps.

Arc Start Switch (K814) – Starts the welding
sequence if remote control for TIG welding is not
desired. Plugs into the Remote Receptacle. The
Current Control switch must be in the LOCAL position
when using the Arc Start switch; only a minimum cur­rent (2 amp) is available in REMOTE. Includes 25 ft.
(7.6 m) cable.

Interface Kit (K846) – Mounts to the back of the LED
status PC board. Provides six isolated circuits that
can be closed to provide status indication when each
of the following functions is active: High Frequency,
Arc Established, Start, Pulse Peak, Pulse Background,
and Crater Fill. Each circuit occupies two positions on
a terminal strip and consists of a fuse, fuse holder, and
sockets for an industry standard, optically isolated
Solid State Relay (SSR) module (purchased separate­ly, see below).

Solid State Relays (SSRs):

K847-DC – Can switch up to 40VDC, 2 amps

maximum load. Package of two.

K847-AC – Can switch up to 130VAC, 2 amp

maximum load. Package of two.

Amptrol™ (K870 or K963) – Provides a remote cur­rent control for most TIG welding applications. Model
K870 is a foot operated control; model 812 is hand
operated. Both models plug into the remote control
receptacle. A separate switch on the Amptrol starts
the welding sequence. When the Current Control
switch on the welder is set in the LOCAL position, the
Amptrol works as an arc start switch only; it does not
control current. (Current is controlled by the rheostat
on the front panel.) When the Current Control switch
on the welder is set to the REMOTE position, current
is controlled by the Amptrol, in a range from 2 amps up
to the current set on the control panel. For a more
detailed explanation of Amptrol operation, see the
Operation Section of this manual.

1

Use of the Synergic 7 wire feeder requires appropriate input cable assembly, wire stand, and drive roll kit. Refer to Synergic 7 Operator’s
Manual for available options.

SQUARE WAVE TIG 355

D-1 D-1

MAINTENANCE

SAFETY PRECAUTIONS

WARNING

• Only Qualified personnel should
perform this maintenance.

• Turn the input power OFF at the
disconnect switch or fuse box
before working on this equipment.

• Do not touch electrically hot parts.

INPUT POWER FACTOR
CAPACITOR DISCHARGE
PROCEDURE

This procedure ensures that the power factor capaci­tors are discharged, for greater safety when you are
working on the Square Wave TIG 355 with INPUT
POWER REMOVED.

1. Remove input power to the machine.

2. With a 5/16" nut driver, remove the sheet metal
screws that hold the right case side in place.
Remove the right case side.

3. With a volt/ohmmeter, carefully check the voltage
across the input power factor capacitors. When
input power is removed, the voltage across each
capacitor should be zero. (Normally, the capaci­tors discharge through the primary winding in the
main transformer.)

4. If capacitor voltage is zero, you may begin working
on the Square Wave TIG 355.

SQUARE WAVE TIG 355

D-2 D-2

MAINTENANCE

5. If any voltage is present, DISCHARGE EACH INDI­VIDUAL CAPACITOR as follows:

a. Obtain a 500 Ohm resistor. Grip the 500 ohm

resistor with insulated gloves and insulated
gripping pliers and hold the resistor across the
terminals on each capacitor for 20 seconds.
See Figure D.1.

b. With the volt/ohmmeter, recheck each capac-

itor for voltage.

6. After all the capacitors are discharged completely,
check for broken capacitor leads or an open pri­mary winding on the main transformer, which
would have prevented the capacitors from dis­charging normally.

ROUTINE AND PERIODIC
MAINTENANCE

WARNING

To avoid receiving a high frequency shock, keep elec­trode holders, TIG torches and cable insulation in
good condition.

1. Disconnect power supply lines to the machine
before performing periodic maintenance.

2. Periodically blow out dust and dirt from the inside
of the machine with a low pressure air system. Be
sure to clean the following components thorough­ly. See Figure D.2 for their location.

• Main transformer

• Output terminals (located on case front)

• Polarity switch (located on case front)

• Rectifier assembly

• Control box assembly

• Spark gap assembly

• Protection PC board

3. Inspect the welder output terminals and control

cables for fraying, cuts, and bare spots.

4. Inspect the spark gap spacing at regular intervals.
To access the spark gap, remove the nameplate
located on the lower right section of the output
panel. Maintain the gap marked on the
machine cover plate. Please note the following:

• If more intensity is needed than is available with

the "High Frequency" set to MAXIMUM,
increase the spark gap according to the inter­vals on the cover plate. (To minimize RFI prob­lems, use the smallest possible spark gap set­ting that still provides good welding.)

• Do not dress or refinish the spark gap contacts.

Replace the electrodes if the contact surfaces
become irregular or completely eroded.

5. The fan motors have sealed ball bearings and
require no maintenance.

FIGURE D.1 – POWER FACTOR CAPACITOR DISCHARGE DETAILS

SQUARE WAVE TIG 355

D-3 D-3

MAINTENANCE

FIGURE D.2 – GENERAL COMPONENT LOCATIONS

1. OUTPUT RECTIFIER/SCR BRIDGE ASSEMBLY

2. INPUT CONTACTOR

3. RECONNECT PANEL

4. PILOT TRANSFORMER

5. FAN AND FAN MOTOR

6. INPUT POWER FACTOR CAPACITOR

7. MAIN TRANSFORMER

8. CHOKE

9. HIGH VOLTAGE TRANSFORMER

10. PC BOARDS (POWER, CONTROL)

11. CASE FRONT

2

1

3

4

5

6

7

10

11

SQUARE WAVE TIG 355

8

9

E-1 E-1

TROUBLESHOOTING

TROUBLESHOOTING GUIDE Observe Safety Guidelines

detailed throughout this manual.

WARNING

ELECTRIC SHOCK can kill.

• Do not touch electrically live parts such
as output terminals or internal wiring.

• Turn the input power off at the fuse box
before working on equiptment.

• Only qualified personnel should
perform this installation.

HOW TO USE THIS GUIDE: Carefully read through each
applicable section listed below. Remember that most prob­lems are caused by improper setup, such as switch settings,
control settings, electrode sizes, improper shielding gases,
etc.

If you believe the setup is correct and the trouble still exists,
first check for the obvious: input power, blown fuses, loose
PC board connectors, broken wires and the like. The sections
listed below are intended to help you find the less obvious
sources of trouble.

General Troubleshooting

Stick Welding Trouble

TIG Welding Trouble

Lower Panel Controls Trouble

Accessory Troubles

GENERAL MACHINE TROUBLE

SYMPTOM CAUSE AND REMEDY

Machine will not turn on. 1. Input supply lines not “hot”. Check input supply line fuses.

2. Blown control circuit fuse (F1). Replace.

3. Thermostat (secondary) has opened. Allow machine to cool
before restarting.

Control circuit fuse (F1) keeps blowing. 1. Machine reconnect panel hooked up for wrong voltage.

Connect per connection diagram in this manual.

2. Fuse is too small. Use 1/2 amp fuse.

3. Shorted control transformer T5. Replace.

4. Defective Power, Meter, Control, or Protection PC board.
Replace PC boards one by one in this order until fuse no
longer blows.

Digital meter does not light, but welder 1. Defective Meter PC board. Replace.
turns on as indicated by the Pilot Light
and fan operation.

Accessories plugged into 115 volt recep- 1. Is accessory defective? Plug it into a known “hot” receptacle
tacle do not work. to check if it works.

Cannot preset a current, but meter lights up. 1. Set control knob to 12 o’clock position. Switch Start function

2. Defective Control PC board. Replace.

2. Circuit Breaker CB1 is open. Before resetting the Circuit
Breaker, find out why it opened. Is the accessory exceeding
the 15 amp maximum load? Is the accessory defective?

OFF. Machine should weld at approximately 80 amps. If
machine welds okay but ammeter does not display the weld­ing current while welding:

a) The Meter PC board may be defective. Replace.
b) The Control PC Board may be defective. Replace.

2. If machine does not weld:

a) Current control pot may be defective. Replace.
b) The Control PC board may be defective. Replace.

WARNING

This Troubleshooting Guide is designed to be used by the machine Owner/Operator. 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, please observe all safety notes and precautions detailed in the Safety
Section of this manual to avoid electrical shock or danger while troubleshooting this equipment.

___________________________________________________________________________________________________________________________________

SQUARE WAVE TIG 355

E-2 E-2

TROUBLESHOOTING

TROUBLESHOOTING GUIDE Observe Safety Guidelines

detailed throughout this manual.

STICK WELDING

SYMPTOM CAUSE AND REMEDY

Machine shuts off in Stick mode. 1. Welder has overheated and secondary thermostat has

opened. Allow welder to cool before attempting to turn
on. Be sure to provide adequate ventilation around
welder to prevent recurrence.

Stick electrode “blasts off” when touched 1. Weld current is set too high for electrode size. Reduce

weld

to workpiece. current.

2. Start Switch is “On”, and Start Current is set too high
for electrode size. Either turn Start Switch OFF, or
reduce Start Current.

3. Arc Force control is set too high. Turn to minimum.

Arc seems too hot, and reducing current 1. Arc Force control is set too high. Turn to minimum.
potentiometer does not help.

2. Start Switch is ON and Start Current is set too high.
Start time may be set too long. Reduce or turn Start
Switch OFF.

Machine welds at very low output, regard- 1. Current Control switch is in REMOTE. Switch to

LOCAL.

less of Current potentiometer setting.

Machine welds at very high output, regard- 1. Are the Start controls set correctly? See “Stick elec-

less of Current potentiometer setting. blasts off” above.

Arc Force control has no effect. 1. The effect of the Arc Force Control will be less notice-

2. Start Switch is ON, and Start Current is set too low for
the electrode size. Either turn Start Switch OFF, or set
Start Current to proper level for the electrode size.

3. Does machine have correct output in TIG mode? If not,
see “Machine welds at low output” in TIG troubleshoot­ing section.

4. If TIG welding output is OK, Control PC board is defec­tive. Replace.

trode

2. Are the TIG welding outputs OK? If not, see TIG trou­bleshooting section.

3. If TIG welding output is OK, Control PC board may be
defective. Replace.

able at high welding currents. Weld at low current (less
than 150 amps) and check Arc Force effect.

2. If no effects are seen at low currents, the Arc Force
control potentiometer may be defective. Replace.

3. Control PC board may be defective. Replace.

Gas and water do not flow even though Gas Machine is operating properly; gas and water solenoids, as

well as

and Water LED is lit in Stick mode. the high frequency circuit, are disabled in the Stick mode.

WARNING

This Troubleshooting Guide is designed to be used by the machine Owner/Operator. 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, please observe all safety notes and precautions detailed in the Safety
Section of this manual to avoid electrical shock or danger while troubleshooting this equipment.

___________________________________________________________________________________________________________________________________

SQUARE WAVE TIG 355

E-3 E-3

TROUBLESHOOTING

TROUBLESHOOTING GUIDE Observe Safety Guidelines

detailed throughout this manual.

TIG WELDING

SYMPTOM CAUSE AND REMEDY

Machine does not respond (no gas flow, no 1. Defective Arc Start Switch or Amptrol. Check for con­high frequency, no open circuit voltage) when tinuity between pins D and E on cable connector when Arc
Arc Start Switch or Amptrol is pressed. Start Switch or Amptrol is pressed.

2. Defective Protection PC board. Replace.

3. Defective Control PC board. Replace.

No gas or water flow when Arc Start Switch 1. Gas supply is empty or not turned on.
is closed in TIG mode.

No High Frequency. 1. High Frequency switch S12 must be in either START or

2. Pinched gas or water hose.

3. Gas and High Frequency fuse (F2) blown. Replace fuse.

4. Gas and High Frequency fuse (F2) is too small. Use 1.5 amp
fuse.

5. Gas and water lines or solenoids are blocked with dirt. Clean
out and use filters to prevent recurrence.

6. Power PC board is defective. Replace.

CONTINUOUS position for high frequency to function.

2. Preflow control is set too long. Reduce Preflow setting. (High
Frequency does not come on until end of preflow period.)

3. Gas and High Frequency fuse (F2) blown. Replace fuse F2.

4. Gas and High Frequency fuse (F2) is too small. Use 1.5 amp
fuse.

5. Spark Gap is too large. Set to gap specified on cover plate.

6. Power PC board is defective. Replace.

Weak high frequency. 1. Spark gap is set too close. Set to 0.015 inches (0.381 mm)

gap for most applications.

2. High Frequency Intensity control set too low. Increase to suit.

3. Work and electrode cables in poor condition, allowing high
frequency to “leak” to ground. Use good quality cables,
preferably those with a high natural rubber content, as short
as possible.

4. No shielding gas. Adjust gas flow for 10 to 30 CFH (4.7 to

14.1 l/min.) for most applications. (High frequency will not
jump from the tungsten to the work without shielding gas.)

Machine shuts down (pilot light goes out 1. If open circuit voltage is greater than 80 volts before shut­and fans stop) when Arc Start Switch or down occurs, Control PC board is defective. Replace.
Amptrol is pressed.

Cannot preset a current on Ammeter when the 1. Defective Arc Start Switch. There should be no continuity
Arc Start Switch or Amptrol is not pressed. between pins D and E of cable connector when Arc Start

Switch or Amptrol is not pressed.

2. Defective Current Control potentiometer. Replace.

3. Defective Control PC board. Replace.

4. Defective Feedthrough PC board. Replace.

SQUARE WAVE TIG 355

E-4 E-4

TROUBLESHOOTING

TROUBLESHOOTING GUIDE Observe Safety Guidelines

detailed throughout this manual.

TIG WELDING (Continued)

SYMPTOM CAUSE AND REMEDY

Machine has gas flow and high frequency but no 1. Turn High Frequency Switch OFF. Look at the two LED’s in
open circuit voltage when the Arc Start Switch the upper left corner of the Power PC board. They should
or Amptrol is pressed. glow when the Arc Start Switch is pressed.

If the LED’s do glow, leads 232A and 233A may be reversed
on the primary of control transformer T5 in control box. Turn
the machine off. Reverse the leads. Turn back on and check
for open circuit voltage. If this does not fix the problem,
restore wires 232A and 233A to their original positions.

If the LED’s do not glow, the Power PC board may be defec­tive. Replace. If the problem still exists, the Control PC board
may be defective. Replace.

Difficulty in getting tungsten to “light off”. 1. Current Control switch is in REMOTE but machine is being

used with an Arc Start Switch and no Amptrol. Set switch to
LOCAL.

2. Start switch is ON, and Start Current is set too low for tung­sten size. Either turn Start switch OFF, or increase Start
Current to proper level for tungsten size.

3. Current control is set too low. Amptrol is not being pressed
far enough for the tungsten size being used. Try in LOCAL
Current Control at a higher current setting. SEE NOTE
BELOW.

4. Contaminated tungsten. If tungsten becomes contaminated
with foreign materials, grind off end of tungsten to expose
fresh electrode. Grind to a point for DC work and leave an
end for AC work.

5. Incorrect tungsten type. Pure or zirconiated is recommended
for AC welding; thoriated is required for DC welding.

6. No shielding gas (or not enough). Adjust gas flow for 10 to
30 CFH (4.7 to 14.1 l/min) for most applications.

Machine welds only at minimum output when 1. Current Control switch is in REMOTE but machine is being
the Current Control switch is in the REMOTE used with an Arc Start Switch and no Amptrol. Set switch to
position. LOCAL.

2. Use LOCAL Current Control. If problem goes away, Amptrol
may be defective. Replace or repair Amptrol.

3. Current Control switch may be defective. Replace.

4. Can machine be preset for currents from 2 to 400 amps? If
not, see “Cannot preset a current” in General
Troubleshooting section.

Arc goes out soon after it is lit. 1. Current Control is set too low, or Amptrol is not being

pressed far enough for the tungsten size being used. SEE
NOTE BELOW.

2. In AC, use Continuous High Frequency.

NOTE: STARTING DIFFICULTIES MAY OFTEN BE DUE TO NOT PRESSING THE AMPTROL FAR ENOUGH.
WHEN THE AMPTROL IS JUST “CRACKED”, THE MINIMUM CURRENT (2 AMPS) IS PRODUCED. PRESSING
THE AMPTROL MORE AT THE START OF THE WELD WILL OFTEN SOLVE STARTING PROBLEMS. Refer to
page 23 for proper use of amptrols.

SQUARE WAVE TIG 355

E-5 E-5

TROUBLESHOOTING

TROUBLESHOOTING GUIDE Observe Safety Guidelines

detailed throughout this manual.

TIG WELDING (Continued)

SYMPTOM CAUSE AND REMEDY

Tungsten is eroding quickly. 1. Current potentiometer is set too high for tungsten size.

Reduce welding current or increase tungsten size.

2. In AC, Wave Balance control may be set too far towards
CLEANING. Turn Balance pot towards PENETRATION, or
increase tungsten size.

Tungsten seems to “spit” when Arc Start Switch High welding current is thermally “shocking” the cold
or Amptrol is pressed at high currents. tungsten causing pieces of the end to spall off. Turn Start

Switch ON, and set Start Current to a value lower than the
welding current to give a “soft” start.

LOWER PANEL CONTROLS

SYMPTOM CAUSE AND REMEDY

Machine does not always wait for Preflow time Machine is operating correctly; it does not go through a
when starting arc. Preflow period if the Arc Start Switch or Amptrol is pressed

during the Afterflow period.

The Spot Time does not last as long as the When in the 2-Step mode, be sure to keep the Arc Start Switch or
nameplate setting. Amptrol pressed until the Spot Time is completed. Releasing the

Arc Start Switch before the Spot Timer has timed out will cause
the arc to go out.

The Spot Time lasts much longer than the The Crater Fill switch should be turned OFF. If it is left ON,
nameplate setting. the actual weld time will be the spot time plus the crater fill time.

The Start Current seems very hot. The Start Current dial is labeled MIN to MAX of the welder

output or, 2 to 400 amps. Always be sure to use the Start Read
pushbutton to check the Start Current preset reading on the digital
ammeter before welding.

The Pulser does not seem to operate. 1. If Start Controls are used, pulsing does not begin until the

end of the start time, which can be as much as 10 seconds.

2. Check the Pulses Per Second control. If it is set near mini­mum, each pulse may be as long as ten seconds. Set all
three of the pulse controls near the midpoints to see the
Pulser’s effects.

3. The Pulse % On control may be set at either extreme. If that
is the case, the pulses may be too short to be seen, depend­ing on the settings of the Current and Background % Current
controls. Set all three of the pulse controls near the mid­points to see the Pulser’s effects.

When using Crater Fill, the arc goes out 1. The Crater Fill % Current control may be set too low for the
before the final Crater Fill Current level tungsten being used. Increase the Crater Fill % Current con­is reached. trol until the final Crater Fill current is within the tungsten’s

operating range.

2. If using the Pulser in conjunction with the Crater Fill, the
Background % Current may be too low for the tungsten as
the current is downsloping in Crater Fill. The best solution is
to increase the Background % Current level.

3. If welding with AC use CONTINUOUS High Frequency. The
high frequency will stabilize the arc as the current goes
down.

SQUARE WAVE TIG 355

E-6 E-6

TROUBLESHOOTING

TROUBLESHOOTING GUIDE Observe Safety Guidelines

detailed throughout this manual.

ACCESSORIES

SYMPTOM CAUSE AND REMEDY

K870 Foot Amptrol or K963 Hand Amptrol.

Amptrol does not control welder output with 1. Check continuity between pins D and E in the cable connec­Current Control switch in REMOTE and tor. There should be an open circuit when the Amptrol is not
Mode switch in TIG. pressed and a short circuit when it is pressed part way. If this

is not the case, check the Amptrol cable for breaks. The
microswitch in the Amptrol may not be operating properly.
Repair or replace as necessary.

2. Using an ohmmeter, check the resistance between pins A
and B in the Amphenol connector. The resistance should be
10K ohms when the pedal is up, and near zero ohms when
the pedal is fully depressed. An open circuit would indicate a
bad cable or defective potentiometer. Check for breaks and
repair or replace the damaged cable or potentiometer.

K814 Arc Start Switch

Arc Start Switch does not start welder output 1. Check continuity between pins D and E of the cable
in TIG Mode and LOCAL Current Control. connector. There should be an open circuit when the switch

is not pressed, and a short circuit when the switch is

pressed.

Check the cable for breaks, and repair or replace as
necessary. Check the switch and its connections.

2. Be sure the 2-Step/4-Step Switch is set correctly.

K846 Interface Kit

Solid State Relay Module output does not close 1. Is the correct type of solid state relay module installed? AC
when corresponding Status PC board LED lights. modules work only for AC circuits, and DC modules only for

DC circuits.

2. Is the corresponding fuse (F1 for CR1, F2 for CR2, etc.)
blown? If so, find cause and replace with a 4 amp fuse.

3. Are the Interface and Status PC boards correctly mated to
one another? Be sure that all 10 pins on P701 are inserted
into J602 on the Status PC board.

4. Is harness connector P601 plugged into J701 on the
Interface PC board?

5. Is Terminal Strip (TS701) wired correctly (terminals 3 and 4
for CR1, terminals 5 and 6 for CR2, etc.)?

6. Is DC polarity of terminal strip connection correct? Odd num­bers (+), even numbers (–).

7. Defective solid state relay. Replace.

Solid State Relay Module output seems to 1. High Frequency pickup may be a problem. Reroute leads
make contact at wrong times. going to Interface terminal strip away from welding cables

which carry high frequency.

2. Use shielded cables to make connections to the Interface PC
board terminal strip. Ground the shield to terminal 1 or 2 on
TS701.

3. Be sure that the white ground lead is on the Interface PC
board tab terminal and is connected to the welder chassis
screw.

SQUARE WAVE TIG 355

F-1 F-1

DUAL VOLTAGE MACHINE

SINGLE VOLTAGE MACHINE

MODE

S10

LOCAL

STICK

CONTINUOUS

REMOTE

TIG

OFF

S11

S12

START

TO GROUND PER NATIONAL ELECTRIC CODE

303

301

302

304

7-25-97C

SQUARE WAVE TIG 355

WIRING DIAGRAM

2519

G

4 STEP

2 STEP

S19

HIGH

FREQUENCY

CURRENT

CONTROL

2 STEP/4 STEP

DIAGRAMS

WIRING DIAGRAM - Square Wave TIG355

SQUARE WAVE TIG 355

F-2 F-2

6-18-93C

17275

M

S.W. TIG 355

K841

50.41

26.00 6.67

15.22

.74

24.12 .94

23.28

22.25

11.12

7.11

20.00

27.65

LOCATION OF .406 MOUNTING HOLES.

*

***

43.93

34.84

45.20

3.25

Ø

DIAGRAMS

DIMENSION PRINT - Square Wave TIG355

SQUARE WAVE TIG 355

F-3 F-3

EQUIPMENT MANUFACTURER’S CERTIFICATION

Type of Equipment

Model Number
Code Number
Serial Number
Operating Instruction Manual Number

This certificate indicates manufacturer’s conformity to FCC Rules & Regulations. User’s
compliance with these regulations requires he fill out this certificate & attach it to the
equipment or other location where it will be conveniently available for inspection.

The High Frequency Generator of the above identified equipment has been tested
under field test condition standards recommended by the Joint Industry Committee on
High Frequency Stabilized Arc Welding Machines. It was found to comply with the
Federal Communications Commission established maximum allowable R. F. energy
radiation limit of 10 micro volts per meter at a distance of 1 mile.

If this equipment is installed, operated and maintained as recommended in the accom­panying manual, it may reasonably be expected to meet the Federal Communications
Commission established R. F. energy radiation limitation.

The Lincoln Electric Company

EQUIPMENT INSTALLATION CERTIFICATION

The above identified equipment has been installed and will be operated and maintained
in compliance with manufacturer’s recommendations made in the accompanying oper­ating manual.

Certifying Signature & Title
Date
THE LINCOLN ELECTRIC COMPANY CLEVELAND, OHIO U.S.A.

S14929 (9-2-83E)

Notes

WARNING

Spanish

AVISO DE

PRECAUCION

● Do not touch electrically live parts or

electrode with skin or wet clothing.

● Insulate yourself from work and

ground.

● No toque las partes o los electrodos

bajo carga con la piel o ropa moja­da.

● Aislese del trabajo y de la tierra.

● Keep flammable materials away.

● Mantenga el material combustible

fuera del área de trabajo.

● Wear eye, ear and body protection.

● Protéjase los ojos, los oídos y el

cuerpo.

French

ATTENTION

German

WARNUNG

Portuguese

ATENÇÃO

Japanese

Chinese

Korean

Arabic

● Ne laissez ni la peau ni des vête-

ments mouillés entrer en contact
avec des pièces sous tension.

● Isolez-vous du travail et de la terre.

● Berühren Sie keine stromführenden

Teile oder Elektroden mit Ihrem
Körper oder feuchter Kleidung!

● Isolieren Sie sich von den

Elektroden und dem Erdboden!

● Não toque partes elétricas e elec-

trodos com a pele ou roupa molha­da.

● Isole-se da peça e terra.

● Gardez à l’écart de tout matériel

inflammable.

● Entfernen Sie brennbarres Material!

● Mantenha inflamáveis bem guarda-

dos.

● Protégez vos yeux, vos oreilles et

votre corps.

● Tragen Sie Augen-, Ohren- und Kör-

perschutz!

● Use proteção para a vista, ouvido e

corpo.

READ AND UNDERSTAND THE MANUFACTURER’S INSTRUCTION FOR THIS EQUIPMENT AND THE CONSUMABLES TO
BE USED AND FOLLOW YOUR EMPLOYER’S SAFETY PRACTICES.

SE RECOMIENDA LEER Y ENTENDER LAS INSTRUCCIONES DEL FABRICANTE PARA EL USO DE ESTE EQUIPO Y LOS
CONSUMIBLES QUE VA A UTILIZAR, SIGA LAS MEDIDAS DE SEGURIDAD DE SU SUPERVISOR.

LISEZ ET COMPRENEZ LES INSTRUCTIONS DU FABRICANT EN CE QUI REGARDE CET EQUIPMENT ET LES PRODUITS A
ETRE EMPLOYES ET SUIVEZ LES PROCEDURES DE SECURITE DE VOTRE EMPLOYEUR.

LESEN SIE UND BEFOLGEN SIE DIE BETRIEBSANLEITUNG DER ANLAGE UND DEN ELEKTRODENEINSATZ DES HER­STELLERS. DIE UNFALLVERHÜTUNGSVORSCHRIFTEN DES ARBEITGEBERS SIND EBENFALLS ZU BEACHTEN.

● Keep your head out of fumes.

● Use ventilation or exhaust to

remove fumes from breathing zone.

● Turn power off before servicing.

● Do not operate with panel open or

guards off.

WARNING

● Los humos fuera de la zona de res-

piración.

● Mantenga la cabeza fuera de los

humos. Utilice ventilación o
aspiración para gases.

● Gardez la tête à l’écart des fumées.

● Utilisez un ventilateur ou un aspira-

teur pour ôter les fumées des zones
de travail.

● Vermeiden Sie das Einatmen von

Schweibrauch!

● Sorgen Sie für gute Be- und

Entlüftung des Arbeitsplatzes!

● Mantenha seu rosto da fumaça.

● Use ventilação e exhaustão para

remover fumo da zona respiratória.

● Desconectar el cable de ali-

mentación de poder de la máquina
antes de iniciar cualquier servicio.

● Débranchez le courant avant l’entre-

tien.

● Strom vor Wartungsarbeiten

abschalten! (Netzstrom völlig öff­nen; Maschine anhalten!)

● Não opere com as tampas removidas.

● Desligue a corrente antes de fazer

serviço.

● Não toque as partes elétricas nuas.

● No operar con panel abierto o

guardas quitadas.

● N’opérez pas avec les panneaux

ouverts ou avec les dispositifs de
protection enlevés.

● Anlage nie ohne Schutzgehäuse

oder Innenschutzverkleidung in
Betrieb setzen!

● Mantenha-se afastado das partes

moventes.

● Não opere com os paineis abertos

ou guardas removidas.

Spanish

AVISO DE

PRECAUCION

French

ATTENTION

German

WARNUNG

Portuguese

ATENÇÃO

Japanese

Chinese

Korean

Arabic

LEIA E COMPREENDA AS INSTRUÇÕES DO FABRICANTE PARA ESTE EQUIPAMENTO E AS PARTES DE USO, E SIGA AS
PRÁTICAS DE SEGURANÇA DO EMPREGADOR.

• World's Leader in Welding and Cutting Products •

• Sales and Service through Subsidiaries and Distributors Worldwide •

Cleveland, Ohio 44117-1199 U.S.A. TEL: [phone] FAX: [phone] WEB SITE: www.lincolnelectric.com