Lincoln Electric SVM118-A User Manual
SERVICE MANUAL
World’s Leader in Welding and Cutting Products Premier Manufacturer of Industrial Motors
Sales and Service through subsidiaries and Distributors Worldwide
22801 St. Clair Ave. Cleveland, Ohio 44117-1199 U.S.A. Tel. (216) 481-8100
SVM118-A
August, 1998
For use with machines having Code Numbers: 9951
9952
9953
9954
9955
SQUARE WAVE TIG 355
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.
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i i
SAFETY
WARNING
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.
ELECTRIC SHOCK can kill.
1.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.
1.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 Reduce Voltage Control.
1.c. In semiautomatic or automatic wire welding, the electrode,
electrode reel, welding head, nozzle or semiautomatic welding gun are also electrically “hot”.
1.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.
1.e. Ground the work or metal to be welded to a good electrical
(earth) ground.
1.f. Maintain the electrode holder, work clamp, welding cable
and welding machine in good, safe operating condition.
Replace damaged insulation.
1.g. Never dip the electrode in water for cooling.
1.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.
1.i. When working above floor level, use a safety belt to protect
yourself from a fall should you get a shock.
1.j. Also see items 4.c. and 6.
2.b. Use suitable clothing made from durable flame-resistant
material to protect your skin and that of your helpers from the
arc rays.
2..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.
out of the fume. Use enough ventilation and/or exhaust at the
arc to keep fumes and gases away from the breathing zone.
When welding with electrodes which require special ventilation such as stainless or hard facing (see instructions on container or MSDS) or on lead or cadmium plated steel and other
metals or coatings which produce highly toxic fumes, keep
exposure as low as possible and below Threshold Limit
Values (TLV) using local exhaust or mechanical ventilation. In
confined spaces or in some circumstances, outdoors, a respirator may be required. Additional precautions are also
required when welding on galvanized steel.
3.b. Do not weld in locations near chlorinated hydrocarbon
vapors coming from degreasing, cleaning or spraying operations. The heat and rays of the arc can react with solvent
vapors to form phosgene, a highly toxic gas, and other irritating products.
3.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.
3.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.
3.e. Also see item 7b.
ARC RAYS can burn.
2.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
Z87.1 standards.
FUMES AND GASES
can be dangerous.
3.a. Welding may produce flames and
gases hazardous to health. Avoid
breathing these fumes and gases.
When welding, keep your head
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SQUARE WAVE TIG 355
ii ii
SAFETY
WELDING SPARKS can
cause fire or explosion.
4.a. Remove fire hazards from the welding area. If this is not possible,
cover them to prevent the welding
sparks from starting a fire.
Remember that welding
sparks and hot 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.
4.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.
4.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.
4.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 though they have
been “cleaned”. For information, purchase “Recommended
Safe Practices for the Preparation for Welding and Cutting of
Containers and Piping That Have Held Hazardous
Substances,” AWS F4.1 from the American Welding Society
(see address above).
4.e. Vent hollow castings or containers before heating, cutting or
welding. They may explode.
4.f. Sparks and spatter are thrown from the welding arc. Wear oil
free protective garments such as leather gloves, heavy shirt,
cuffless trousers, high shoes and a cap over your hair. Wear
eat plugs when welding out of position or in confined places.
Always wear safety glasses with side shields when in a welding area.
4.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.
4.h. Also see item 7c.
CYLINDER may explode
if damaged.
5.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.
5.b. Always keep cylinders in an upright position securely
chained to an undercarriage or fixed support.
5.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.
5.d. Never allow the electrode, electrode holder or any other electrically “hot” parts to touch a cylinder.
5.e. Keep your head and face away from the cylinder valve outlet
when opening the cylinder valve.
5.f. Valve protection caps should always be in place and hand
tight except when the cylinder is in use or connected for use.
5.g. Read and follow the instructions on compressed gas cylinders, associated equipment, and CGA publication P-I,
“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.
6.a. Turn off input power using the disconnect switch at the fuse box
before working on the equipment.
6.b. Install equipment in accordance with the U.S. National
Electrical Code, all local codes and the manufacturer’s recommendations.
6.c. Ground the equipment in accordance with the U.S. National
Electrical Code and the manufacturer’s recommendations.
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SQUARE WAVE TIG 355
iii iii
SAFETY
FOR ENGINE
powered equipment.
7.a. Turn the engine off before troubleshooting and maintenance
work unless the maintenance work requires it to be running.
7.b. Operate engines in open, well-ventilated
areas or vent the engine exhaust fumes
outdoors.
7.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.
7.d. Keep all equipment safety guards, covers
and devices in position and in good
repair. Keep hands, air, clothing and
tools away from V-belts, gears, fans and
all other moving parts when starting,
operating, or repairing equipment.
ELECTRIC AND MAGNETIC
FIELDS
may be dangerous
8.a. Electric current flowing through any conductor causes localized Electric and Magnetic Fields (EMF). Welding current cr eates EMF fields around welding cables and welding
machines.
8.b. EMF fields may interfere with some pacemakers, and welders
have a pacemaker should consult their physician before
welding.
8.c. Exposure to EMF fields in welding may have other health
effects which are now not known.
8.d. All welders should use the following procedures in order to
minimize exposure to EMF fields from the welding circuit:
8.d.1. Route the electrode and work cables together -
Secure them with tape when possible.
8.d.2. Never coil the electrode lead around your body.
8.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.
8.d.4. Connect the work cable to the workpiece as close as
possible to the area being welded.
8.d.5. Do not work next to welding power source.
7.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.
7.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.
7.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.
7.h. To avoid scalding, do not remove the
radiator pressure cap when the engine
is hot.
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SQUARE WAVE TIG 355
iv iv
SAFETY
PRÉCAUTIONS DE SÛRETÉ
Pour votre propre protection lir e 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 ten-
sion 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.
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
enroule 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 rayonnementde
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 laiter en fusion sont émises de l’arc de
soudage. Se protéger avec es 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.
6. Eloigner les matériaux inflammables ou les recouvrir afin de
prévenir ttout risque d’incendie dû 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 la 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 atres 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 fumées toxiques.
10. Ne pas souder en présence de vapeurs de chlore provenant
d’opéerations 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 roxique) ou autres produits irritants.
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, l’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 dispostifis de sûreté à leur
place.
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SQUARE WAVE TIG 355
v v
MASTER TABLE OF CONTENTS FOR ALL SECTIONS
RETURN TO MAIN INDEX
Safety .................................................................................................................................................i-iv
Installation.............................................................................................................................Section A
Installation Section Table of Contents........................................................................................A-1
Technical Specifications .............................................................................................................A-2
Safety Precautions ......................................................................................................................A-3
Select Suitable Location (Stacking, Tilting, Lifting)....................................................................A-3
High Frequency Interference Protection.....................................................................................A-3
Input Connections.......................................................................................................................A-4
Reconnect Procedure.................................................................................................................A-5
Output Connections....................................................................................................................A-7
Operation...............................................................................................................................Section B
Safety Instructions......................................................................................................................B-2
General Description....................................................................................................................B-3
Recommended Processes..........................................................................................................B-3
Operational Features and Controls ............................................................................................B-3
Design Features and Advantages...............................................................................................B-3
Welding Capability ......................................................................................................................B-4
Limitations .................................................................................................................................B-4
Controls and Settings (Upper and Lower Case Front Controls)................................................B-5
Welding Operation....................................................................................................................B-15
Overload Protection ..................................................................................................................B-21
Auxiliary Power.........................................................................................................................B-21
Page
Accessories...........................................................................................................................Section C
Maintenance .........................................................................................................................Section D
Safety Precautions......................................................................................................................D-2
Input Power Factor Capacitor Discharge Procedure.................................................................D-2
Routine and Periodic Maintenance ............................................................................................D-3
General Component Locations...................................................................................................D-4
Theory of Operation .............................................................................................................Section E
Troubleshooting and Repair.................................................................................................Section F
How To Use Troubleshooting Guide...........................................................................................F-2
Troubleshooting Guide................................................................................................................F-4
Electrical Diagrams..............................................................................................................Section G
Parts Manual.................................................................................................................................P-196
SQUARE WAVE TIG 355
Section A-1 Section A-1
TABLE OF CONTENTS
- INSTALLATION SECTION -
Installation
Technical Specifications Square Wave TIG 355 .........................................................................A-2
Input and Output Specifications ..........................................................................................A-2
Cable and Fuse Sizes...........................................................................................................A-2
Physical Dimensions ............................................................................................................A-2
Safety Precautions ......................................................................................................................A-3
Select Suitable Location.............................................................................................................A-3
Stacking................................................................................................................................A-3
Lifting .................................................................................................................................A-3
Tilting .................................................................................................................................A-3
High Frequency Precautions.......................................................................................................A-3
Input Connections.......................................................................................................................A-4
Ground Connection..............................................................................................................A-4
Input Supply Connections ....................................................................................................A-4
Reconnect Procedure.................................................................................................................A-5
Output Connections....................................................................................................................A-7
TIG Torch Connection ..........................................................................................................A-7
Stick Electrode Cable Connection.......................................................................................A-8
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SQUARE WAVE TIG 355
A-2 A-2
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
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0° to 40°C -50° to 85°C
SQUARE WAVE TIG 355
A-3 A-3
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.
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.
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SQUARE WAVE TIG 355
A-4 A-4
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.
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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.
SQUARE WAVE TIG 355
A-5 A-5
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 type1circuit breakers. Choose an input
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 r esult
in “nuisance” shut-offs from welder inrush currents
even if not welding at high curents.
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.
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SQUARE WAVE TIG 355
A-6 A-6
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
200/50 115 4 6 150
220/50 104 4 6 125
440/50 52 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.
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SQUARE WAVE TIG 355
A-7 A-7
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
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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 (45mm2) 1/0 (55mm2) 2/0 (70mm2)
SQUARE WAVE TIG 355
A-8 A-8
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.
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SQUARE WAVE TIG 355
Section B-1 Section B-1
TABLE OF CONTENTS
- OPERATION SECTION -
Operation...............................................................................................................................Section B
Safety Instructions ...............................................................................................................B-2
General Description....................................................................................................................B-3
Recommended Processes...................................................................................................B-3
Operational Features and Controls......................................................................................B-3
Design Features and Advantages........................................................................................B-3
Welding Capability................................................................................................................B-4
Limitations............................................................................................................................B-4
Controls and Settings.................................................................................................................B-5
Upper Case Front Controls..................................................................................................B-5
Lower Case Front Controls................................................................................................B-11
Hand and Foot Amptrol™ Operation.................................................................................B-13
Welding Operation....................................................................................................................B-15
Initial Start-up .....................................................................................................................B-15
Stick Welding ....................................................................................................................B-15
TIG Welding Guidelines......................................................................................................B-15
TIG Welding Sequence of Operation (2-Step Mode).........................................................B-20
TIG Welding Sequence of Operation (4-Step Mode).........................................................B-20
Overload Protection ..................................................................................................................B-21
Auxiliary Power.........................................................................................................................B-21
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SQUARE WAVE TIG 355
B-2 B-2
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.
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SQUARE WAVE TIG 355
B-3 B-3
OPERATION
GENERAL DESCRIPTION
The Square Wave TIG 355 is a constant curr ent, 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 featur es
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.)
DESIGN FEATURES AND ADVANTAGES
• Designed to NEMA EW-1 and Inter national 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, Ar c For ce curr ent contr ol
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.
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• Built-In High Frequency Generator.
SQUARE WAVE TIG 355
B-4 B-4
OPERATION
• 115 Volt receptacle with 15 amp circuit breaker.
• 220 Volt European (Schuko) type receptacle with 2
amp circuit breaker for water coolers (50/60Hz
machines only).
• 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.
• 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.
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.
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.
• 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.
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SQUARE WAVE TIG 355
B-5 B-5
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 ar e 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
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
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12
13
14
15
SQUARE WAVE TIG 355
16
17
B-6 B-6
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.
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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-7 B-7
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™: This setting provides automatic 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:
.
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™LED
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
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.
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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.
SQUARE WAVE TIG 355
B-8 B-8
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.
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 begin-
ning 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.
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.
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 num-
ber 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
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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-9 B-9
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 cur-
rent 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.
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FIGURE B.2 – STATUS INDICATOR LIGHT SEQUENCE
SQUARE WAVE TIG 355
SQUARE WAVE TIG 355
B-10 B-10
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.
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SQUARE WAVE TIG 355
B-11 B-11
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
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SQUARE WAVE TIG 355
B-12 B-12
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.
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SQUARE WAVE TIG 355
B-13 B-13
OPERATION
HAND AND FOOT AMPTROL OPERATION
Both the Hand and Foot Amptrol (optional kits K870 or
K812) 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.
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SQUARE WAVE TIG 355
B-14 B-14
OPERATION
FIGURE B.4 – AMPTROLS USED WITH CURRENT CONTROL IN THE LOCAL POSITION
FIGURE B.5 – AMPTROLS USED WITH CURRENT CONTROL IN REMOTE POSITION
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SQUARE WAVE TIG 355
B-15 B-15
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 K812
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 corr ect
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.
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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-16 B-16
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
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SQUARE WAVE TIG 355
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