Lincoln Electric SVM129-B User Manual
SVM129-B
OCTOBER, 2006
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.
For use with machine code numbers:10151,10152,10153,10309,10381,10382,10383,11090,11091,11092,
11115,11116
INVERTEC
®
STT
TM
& STT II
TM
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
View Safety Info View Safety Info View Safety Info View Safety Info
SERVICE MANUAL
• Sales and Service through Subsidiaries and Distributors Worldwide •
Cleveland, Ohio 44117-1199 U.S.A. TEL: 1-888-935-3877 FAX: 216.486.1751 WEB SITE: www.lincolnelectric.com
• World's Leader in Welding and Cutting Products •
Copyright © 2006 Lincoln Global Inc.
RETURN TO MAIN MENU
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
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.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.
i
SAFETY
i
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.
WARNING
Mar ‘95
ELECTRIC AND
MAGNETIC FIELDS
may be dangerous
2.a. Electric current flowing through any conductor causes
localized Electric and Magnetic Fields (EMF). Welding
current creates EMF fields around welding cables and
welding machines
2.b. EMF fields may interfere with some pacemakers, and
welders having a pacemaker should consult their physician
before welding.
2.c. Exposure to EMF fields in welding may have other health
effects which are now not known.
2.d. All welders should use the following procedures in order to
minimize exposure to EMF fields from the welding circuit:
2.d.1.
Route the electrode and work cables together - Secure
them with tape when possible.
2.d.2. Never coil the electrode lead around your body.
2.d.3. Do not place your body between the electrode and
work cables. If the electrode cable is on your right
side, the work cable should also be on your right side.
2.d.4. Connect the work cable to the workpiece as close as
possible to the area being welded.
2.d.5. Do not work next to welding power source.
1.h. To avoid scalding, do not remove the
radiator pressure cap when the engine is
hot.
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 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 Diesel Engines
The Above For Gasoline Engines
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
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.
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.
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. The operation of welding fume control equipment is affected
by various factors including proper use and positioning of the
equipment, maintenance of the equipment and the specific
welding procedure and application involved. Worker exposure level should be checked upon installation and periodically thereafter to be certain it is within applicable OSHA PEL
and ACGIH TLV limits.
5.c.
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.
5.d. 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.e. Read and understand the manufacturer’s instructions for this
equipment and the consumables to be used, including the
material safety data sheet (MSDS) and follow your
employer’s safety practices. MSDS forms are available from
your welding distributor or from the manufacturer.
5.f. Also see item 1.b.
AUG 06
ii
SAFETY
ii
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
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.
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.
Mar ‘95
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.
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.
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
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).
6.e. Vent hollow castings or containers before heating, cutting or
welding. They may explode.
6.f.
Sparks and spatter are thrown from the welding arc. Wear oil
free protective garments such as leather gloves, heavy shirt,
cuffless trousers, high shoes and a cap over your hair. Wear
ear plugs when welding out of position or in confined places.
Always wear safety glasses with side shields when in a
welding area.
6.g. Connect the work cable to the work as close to the welding
area as practical. Work cables connected to the building
framework or other locations away from the welding area
increase the possibility of the welding current passing
through lifting chains, crane cables or other alternate circuits.
This can create fire hazards or overheat lifting chains or
cables until they fail.
6.h. Also see item 1.c.
iii
SAFETY
iii
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
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.
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.
6. Eloigner les matériaux inflammables ou les recouvrir afin de
prévenir tout risque d’incendie dû aux étincelles.
7. Quand on ne soud
e 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.
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
iv
SAFETY
iv
MASTER TABLE OF CONTENTS FOR ALL SECTIONS
v v
INVERTEC STT
Page
Safety.................................................................................................................................................i-iv
Installation.............................................................................................................................Section A
Operation...............................................................................................................................Section B
Accessories ..........................................................................................................................Section C
Maintenance..........................................................................................................................Section D
Theory of Operation .............................................................................................................Section E
Troubleshooting and Repair................................................................................................Section F
Electrical Diagrams..............................................................................................................Section G
STT Parts .......................................................................................................................................P257
STT II Parts....................................................................................................................................P294
RETURN TO MAIN MENU
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
TABLE OF CONTENTS
- INSTALLATION SECTION -
Section A-1 Section A-1
INVERTEC STT
Installation .............................................................................................................................Section A
Technical Specifications (Codes 11092 & Below) .......................................................................A-2
Technical Specifications (Codes 11115 & 11116) ........................................................................A-3
Location.......................................................................................................................................A-4
Stacking.......................................................................................................................................A-4
Tilting...........................................................................................................................................A-4
Machine Grounding and High Frequency Interference Protection..............................................A-4
Input Connections .......................................................................................................................A-4
Supply Connections..............................................................................................................A-4
Input Cable Installation and Connection...............................................................................A-5
Ground Connection...............................................................................................................A-5
Input Voltage Reconnect Procedure ...........................................................................................A-6
Output Connections ....................................................................................................................A-6
Wire Feeder Output Connections .........................................................................................A-6
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
INSTALLATION
A-2 A-2
INVERTEC STT
STANDARD VOLTAGE INPUT CURRENT AT RATED OUTPUT
208/230/460/3/60 HZ 32/30/16
200/220/380/415/440/3/50/60 HZ 33/30/18/17/16
TECHNICAL SPECIFICATIONS –Invertec STT & STT II (For Codes 11092 and BELOW)
INPUT- THREE PHASE ONLY
RATED OUTPUT
RECOMMENDED INPUT WIRE AND FUSE SIZES
INPUT VOLTAGE FUSE(SUPER LAG) INPUT AMPERE TYPE 75 C TYPE 75 C
AND FREQUENCY OR BREAKER RATING ON COPPER COPPER
SIZE NAMEPLATE SUPPLY WIRE GROUND WIRE
IN CONDUIT IN CONDUIT
AWG (IEC) SIZES AWG (IEC) SIZES
208/60 40 32
230/60 40 30
460/60 30 16
200/50/60 40 33
220/50/60 40 30 10 (6 mm2) 10 (6 mm2)
380/50/60 30 18
415/50/60 30 17
440/50/60 30 16
HEIGHT WIDTH DEPTH WEIGHT
23.2 in 13.2 in. 24.4 in. 100 lbs.
589 mm 336 mm 620 mm 46 kg
OUTPUT
DUTY CYCLE AMPS VOLTS AT RATED AMPS
60% Duty Cycle 225 29
100% Duty Cycle 200 28
CURRENT RANGE OPEN CIRCUIT VOLTAGE AUXILIARY POWER
Peak Current
1
0 - 450 Amps 85 VDC Maximum 115 2VAC @ 4 Amps
Background 0 - 125 Amps 42 VAC @ 4 Amps
1
At low input voltages (below 208 VAC) and input voltages of 380 VAC through 415 VAC there may be a 15% reduction in Peak Current.
2
115 VAC not present on European Models.
PHYSICAL DIMENSIONS
INSTALLATION
A-3 A-3
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
STANDARD VOLTAGE INPUT CURRENT AT RATED OUTPUT
200/208/3/50/60 HZ 36/34
200/208/380/400/415/3/50/60 HZ 36/34/20/19/18
TECHNICAL SPECIFICATIONS –Invertec STT II (For Codes 11115 AND 11116)
INPUT- THREE PHASE ONLY
RATED OUTPUT
RECOMMENDED INPUT WIRE AND FUSE SIZES
INPUT VOLTAGE FUSE(SUPER LAG) INPUT AMPERE TYPE 75 C TYPE 75 C
AND FREQUENCY OR BREAKER RATING ON COPPER COPPER
SIZE NAMEPLATE SUPPLY WIRE GROUND WIRE
IN CONDUIT IN CONDUIT
AWG (IEC) SIZES AWG (IEC) SIZES
200/50/60 40 36
208/50/60 40 34
380/50/60 30 20 10 (6 mm2) 10 (6 mm2)
400/50/60 30 19
415/50/60 30 18
HEIGHT WIDTH DEPTH WEIGHT
23.2 in 13.2 in. 24.4 in. 100 lbs.
589 mm 336 mm 620 mm 46 kg
OUTPUT
DUTY CYCLE AMPS VOLTS AT RATED AMPS
60% Duty Cycle 225 29
100% Duty Cycle 200 28
CURRENT RANGE OPEN CIRCUIT VOLTAGE AUXILIARY POWER
Peak Current 0 - 450 Amps 88 VDC Maximum 115
1
VAC @ 4 Amps
Background 0 - 125 Amps 42 VAC @ 4 Amps
1
115 VAC not present on European Models.
PHYSICAL DIMENSIONS
INSTALLATION
A-4 A-4
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
ELECTRIC SHOCK can kill.
• Only qualified personnel should
perform this installation.
•Turn the input power OFF at the
disconnect switch or fuse box
before installing this
equipment.
•Turn the power switch on the Invertec
STT “OFF” before connecting or disconnecting input power lines, output cables,
or control cables.
• Do not touch electrically hot
parts.
• Always connect the ground terminal to a
good electrical earth ground.
WARNING
MACHINE GROUNDING AND HIGH
FREQUENCY INTERFERENCE
PROTECTION
The machine may not be suitable for use in an environment where high frequency is present. For example do not place the machine in close proximity to “TIG”
or “PLASMA” operations. To minimize high frequency
interference:
Locate the STT II power source more than 15
feet (4.5 m) away from high frequency units
and more than 25 feet (7.6 m) separation
between ground connections or welding arcs
of high frequency units.
Provide proper electrical ground to the
machine per local and national electrical
codes.
INPUT CONNECTIONS
FAILURE TO FOLLOW THESE INSTRUCTIONS
CAN CAUSE IMMEDIATE FAILURE OF COMPONENTS WITHIN THE WELDER.
Turn the input power off at the disconnect switch
before attempting to connect the input power lines.
Connect the green lead of the power cord to ground
per local and national electrical codes.
SUPPLY CONNECTIONS
Be sure the voltage, phase, and frequency of the input
supply is as specified on the rating plate. Input Power
supply line entry in provided on the case back of the
machine. See figure A.1 for location of the rating plate.
The Invertec STT II should be connected only by a
qualified electrician. Installation should be made in
accordance with local and national codes. Refer to the
“Technical Specifications” at the beginning of this
section for proper fuse sizes, ground wire, and input
supply power cable sizes.
Some models come from the factory with an input
power cord. If your model does not include the input
power cord install the proper size input cable and
ground cable according to “INPUT CABLE INSTAL-
LATION AND CONNECTION”.
SELECT SUITABLE LOCATION
Locate the machine where there is free circulation of
clean air. Place the machine so that air can freely circulate into the sides and out of the rear of the
machine. Dirt and dust that can be drawn into the
machine should be kept to a minimum. Failure to
observe these precautions can result in excessive
operating temperatures and nuisance shut down of the
Invertec STT II.
This machine carries an enclosure rating of IP21S. It
should not be placed in extremely damp or dirty locations. It should not be exposed to rain or snow.
STACKING
The Invertec STT II cannot be stacked.
TILTING
Place the machine on a secure, level surface otherwise
the unit may topple over.
Read and understand entire Installation
Section before starting installation.
INSTALLATION
A-5 A-5
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
INPUT CABLE INSTALLATION AND CONNECTION
A cable strain relief is provided at the supply line entry
and is designed to accommodate cable diameters of
.310 - 1.070 in. (7.9 - 27.2 mm). On European models
the strain relief is designed to accommodate cable
diameters of .709 - 1.000 in. (18.0 - 25.4 mm). Refer to
“Technical Specifications” at the beginning of this section for the proper input cable sizes. Refer to Figure A.1
and perform the following steps:
1. Remove the wraparound cover of the
Invertec STT II.
2. Feed the input cable through the input cable
entry access hole at the right rear of the
machine.
3. Route the cable through the cable hangers,
located along the lower right inside edge of
the machine, up to the power switch located on
the front panel.
4. Strip away 102 mm (4 in.) of the outer jacket.
Trim fillers and strip conductor jackets to
connect to the power switch.
5. Connect the three phase line conductors to the power switch terminals labeled U, V and W. Tighten
the connections to 3.0 Nm. (27 in.-lb.) torque.
6. Securely tighten the cable strain relief located
on the case back of the machine.
GROUND CONNECTION
1. Connect the ground terminal to earth
ground per National Electrical Code.
2. Replace the wraparound cover of the
Invertec STT II.
CASE BACK
RATING PLATE
INPUT CABLE
ENTRY ACCESS
& CABLE STRAIN RELIEF
FIGURE A.1 CASE BACK
A-6
INSTALLATION
A-6
INVERTEC STT II
FIGURE A.2 RECONNECT PANEL
I
NPUT VOLTAGE RECONNECT
PROCEDURE
As shipped from the factory, multiple voltage machines
are internally configured for the highest input voltage
(440-460 VAC), for Codes 11092 and below and (380415 VAC), for Codes 11115 and 11116.
1. For Connections to 440 or 460 VAC verify
the internal configurations to the procedures shown below and
refer to Figure A.2.
2. For Connections to 200,208,220,230,380,400 or 415
VAC follow the procedure shown below and refer to figure A.2.
NOTE: Turn main power to the machine OFF
before performing the reconnect procedure.
Failure to do so will result in damage to the
machine. DO NOT switch the reconnect bar with
machine power ON.
------------------------------------------------------------------------
To Operate at Procedure
460 or 440 VAC 1. Open reconnect panel
(Codes 11092 and access door on wraparound.
below) 2. Move input voltage switch
to Voltage = 380 -460V position.
3. Move lead “A” to 440-460
Terminal.
380 or 415 VAC 1. Open reconnect panel
(Codes 11092 and access door on wraparound.
below)
2. Move input voltage switch
to Voltage = 380-460V
position.
3. Move lead “A” to 380-415
Terminal.
380,400 or 415 VAC 1. Open reconnect panel
(Codes 11115 and access door on wraparound.
11116) 2. Move input voltage switch
to Voltage = 380-460V
position.
3. Move lead “A” to 380-415
Terminal.
220 or 230 VAC 1. Open reconnect panel
(Codes 11092 and access door on wraparound.
below) 2. Move input voltage switch
to Voltage = 200 -230V
position.
3. Move lead “A” to 220-230
Terminal.
200 or 208 VAC 1. Open reconnect panel
(Codes 11092 and access door on wraparound.
below) 2. Move input voltage switch
to Voltage = 200 -230V
position.
3. Move lead “A” to 200-208
Terminal.
200 or 208 VAC 1. Open reconnect panel
(Codes 11115 and access door on wrap-around.
11116) 2. Move input voltage switch
to Voltage = 200 -230V
position.
3. Move lead “A” to 200-208
Terminal.
OUTPUT CONNECTIONS
WIRE FEEDER OUTPUT CONNECTIONS
Refer to the Accessories section of this manual for
instructions on connecting a wire feeder to the Invertec
STT II.
The LN-742 or STT-10 wire feeder is the recommended feeder for use with the Invertec STT II.
WARNING
4A
380-415
OR
OR
200-208
*
*
*
(NOT PRESENT ON ALL MODELS)
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
Section B-1 Section B-1
INVERTEC STT
TABLE OF CONTENTS
- OPERATION SECTION -
Operation...............................................................................................................................Section B
Safety Precautions ......................................................................................................................B-2
General Description ....................................................................................................................B-3
Recommended Equipment..........................................................................................................B-3
Operating Controls ......................................................................................................................B-3
Design Features..........................................................................................................................B-3
Welding Capability ......................................................................................................................B-3
Limitations ...................................................................................................................................B-3
Operational Features and Controls.............................................................................................B-4
Welding Operation ......................................................................................................................B-5
Welding Parameters and Guidelines ..........................................................................................B-6
Recommended Settings for STT II..............................................................................................B-7
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
B-2 B-2
INVERTEC STT
ELECTRIC SHOCK
can kill.
• Do not touch electrically live parts
or electrode with skin or wet
clothing.
• Insulate yourself from 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.
OPERATING INSTRUCTIONS
Read and understand entire section before
operating machine.
GENERAL WARNINGS
SAFETY PRECAUTIONS
Observe additional Safety Guidelines detailed in the beginning of this manual.
WARNING
OPERATION
OPERATION
B-3 B-3
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
GENERAL DESCRIPTION
The Invertec STT II is a 225-ampere inverter based arc
welding power source specifically designed for the STT
welding process. It is neither a constant current (CC)
nor a constant voltage (CV) machine. It is a power
source that delivers current of a desired wave form and
characteristics that are superior to conventional short
circuiting GMAW. The process is optimized for shortcircuiting GMAW welding.
RECOMMENDED EQUIPMENT
The LN-742 or STT-10 wire feeder is recommended for
use with the STT II. The LN-7 GMA, LN-9 GMA, NA-5,
and NA-5R can all be used with the STT II. However,
these units can only be used to feed wire since these
feeders have no provision for control of the STT output.
OPERATING CONTROLS
The Invertec STT II has the following controls as standard: On/Off switch, Peak Current adjustment,
Background Current adjustment, Hot Start adjustment,
Tailout, and 2 toggle switches; one for wire size selection and one for wire type selection.
DESIGN FEATURES AND ADVANTAGES
• State of the art inverter technology yields high power
efficiency, excellent welding performance, lightweight and compact design.
• Twist-Mate™ output terminals.
• Digital meters for procedure settings are standard.
• Automatic Inductance or Pinch Control.
• Solid state circuitry for extra long component life.
• Current feedback ensures that original procedure
settings all remain constant.
• Arc Sense lead assembly (Electrode and Work),
connects through a 4-pin case front connector.
• Peak Current and Background Current may be
remotely controlled.
• Thermostat and FET over current protector prevent
overheating from overloads, high ambient temperatures, or loss of air flow.
• High temperature Class H insulation.
• Protection circuits and ample safety margins prevent
damage to the solid state components from transient
voltages and high currents.
• Preset welding current capability.
• STT II offers improvements over the previous model.
Approximately 40% increase in deposition rate capability, and a significant increase in travel speed.
WELDING CAPABILITY
The Invertec STT II is rated at 225 amps, 29 volts, at
60% duty cycle on a ten minute basis. It is capable of
higher duty cycles at lower output currents. If the duty
cycle(s) are exceeded, a thermal protector will shut off
the output until the machine cools to a reasonable
operating temperature.
LIMITATIONS
• May not be suitable for use in an environment with
High Frequency present. (“See Machine Grounding
and High Frequency Protection” in the Installation
section of this manual)
• Suitable for indoor use only (IEC IP21S).
OPERATION
B-4 B-4
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
1. POWER SWITCH: Turns output
power ON and OFF. This switch
also controls auxiliary power
available through the 14-pin Wire
Feeder Receptacle.
2A. BACKGROUND CURRENT OUTPUT CONTROL:
The output current is switched to the
Background level at the conclusion of the
preceding Peak Current pulse. This knob
allows preset adjustment of the amplitude
of the background current up to 125
amperes.
2B. BACKGROUND CURRENT DISPLAY METER:
This is a digital meter for displaying the
preset Background Current. This meter
displays in 1 amp increments. This meter
does not indicate the actual welding current, only the preset current.
3A. PEAK CURRENT OUTPUT CONTROL: The
beginning portion of the welding arc is a
pulse of current referred to as Peak
Current. This knob allows preset adjustment of the amplitude of the peak current
up to 450 amperes.
3B. PEAK CURRENT DISPLAY METER: This
is a digital meter for displaying the preset
Peak Current. This meter displays in 1
amp increments. This meter does not indi
cate actual welding current only the preset
current.
4. HOT START CONTROL POTENTIOMETER:
“Hot Start” provides approximately 25% to
50% more current during the initial start of
the weld for improved arc starting and bead
appearance. This control adjusts the duration of this “Hot Start” current. The control range is
from 0 to 10, where 0 corresponds to the zero or no
“Hot Start”, and 10 is maximum for a “Hot Start” lasting for about four (4) seconds.
5. TAILOUT: Alters the current waveform to increase
deposit rate and travel speed. The Minimum setting
sets STT II to the original STT waveform. As tailout
is increased peak and Background current may
need to be reduced to maintain optimum performance.
OPERATIONAL FEATURES AND CONTROLS
All operator controls are located on the case front of the Invertec STT II. Refer to Figure B.1 for locations.
FIGURE B.1 CASE FRONT CONTROLS
4
1
2
3
7
6
8
10
9
11
14
15
12
13
5
ON
OFF
AAV
OPERATION
B-5 B-5
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
6. WIRE SIZE SELECT SWITCH: This toggle switch
selects between electrode diameters of .035” (1 mm)
and smaller or .045” (1.2 mm) and larger. The .035”
(1 mm) position provides improved performance of
smaller diameter wires at higher wire feed speeds.
7. WIRE TYPE SELECT SWITCH: This toggle switch
selects between mild or stainless steel. In the stainless position, the pulse width of the Peak Current is
changed from 1 to 2 ms for better performance for
stainless steel welding.
8. THERMAL SHUT-DOWN INDICATOR: This light
will indicate that either the internal thermostat(s) or the FET over current sensor has
actuated. Machine output will return after
the internal components have returned to normal
operating temperature (if the thermostat(s)
“opened”) or after about 3-7 seconds (if the FET over
current sensor activated).
9.
REMOTE RECEPTACLE: This is a 10 pin MS-type
connector for remote control of Peak Current and
Background Current. Trigger switch connections
are also provided. The presence of the mating connector is automatically sensed, disabling the front panel Peak
and Background Current controls. Refer to “REMOTE CONTROL CONNECTOR” in the ACCESSORIES Section of this
manual for more information.
10. WIRE FEEDER RECEPTACLE: This is 14
pin MS-type connector for the wire feeder
connection. 115 and 42 VAC along with
the trigger switch connections are provided. (Only 42 VAC is available on European models). There are no provisions for voltage control of
the power source by the wire feeder. Refer to the
Accessories section of this manual for wire feeder
connection instructions.
11. ARC SENSE RECEPTACLE:
This is a four pin MStype connector for WORK and ELECTRODE sense
leads. The STT requires a WORK sense and ELECTRODE sense lead for proper operation. The
ELECTRODE sense lead is bolted together with
power source electrode lead at the wire feeder gun
block. The WORK sense lead is furnished with an
“alligator” type clip for connection to the work piece.
Refer to the LN 742 or STT-10 wire feeder connection instructions in the Accessories section of this
manual for proper connection of these leads.
12. 42V AUXILIARY POWER CIRCUIT BREAKER:
The 42 VAC supply is protected from excessive current
draws with a 6 amp circuit breaker. When the
breaker “trips” its button will extend.
Depressing this button will reset the breaker.
13. 115V AUXILIARY POWER CIRCUIT BREAKER
(Not on European Models): The 115 VAC
supply is protected from excessive current
draws with a 6 amp circuit breaker. When
the breaker “trips” its button will extend.
Depressing this button will reset the breaker.
14. WORK TERMINAL: This twist-mate con-
nection is the negative output terminal for
connecting a work cable and clamp to the
workpiece.
15. ELECTRODE TERMINAL: This twist-mate
connection is the positive output terminal
for connecting an electrode cable to the
wire feeder conductor block. Refer to the
Accessories Section for wire feeder connection
instructions.
WELDING OPERATION
Familiarize yourself with the controls on the Invertec
STT II before beginning to weld.
Familiarize yourself with the operating manual for the
wire feeder and the wire feeder controls before beginning to weld.
Set the Wire Size and Wire Type selection switches per
the appropriate wire. Refer to “Operational Features
and Controls” in this section for the function of these
switches.
OPERATION
B-6 B-6
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
WELDING PARAMETERS AND GUIDELINES
The Invertec STT II is neither a constant current (CC)
nor a constant voltage (CV) power source. In general,
wire diameter will be increased one size compared to
conventional (CV) power sources. The larger the wire
diameter the higher the deposition rate (Up to 1/16”).
Wire sizes below .035” are unnecessary for most applications. The Invertec STT II is a current controlled
machine which is capable of changing the electrode
current quickly in order to respond to the instantaneous
requirements of the arc and optimize performance.
By sensing changes in welding current, and hence the
electrode state, the power source will supply varying
output currents to minimize spatter. The Peak and
Background currents are two such current outputs that
can be adjusted.
Wire Feed Speed controls the deposition rate. Peak
Current controls the Arc Length. Background Current
controls the Bead Contour. And Tailout increases
Power in the Arc.
PEAK CURRENT
The Peak Current control acts similar to an “arc pinch”
control. Peak current serves to establish the arc length
and promote good fusion. Higher peak current levels
will cause the arc to broaden momentarily while
increasing the arc length. If set too high, globular type
transfer will occur. Setting this level to low will cause
instability and wire stubbing. In practice, this current
level should be adjusted for minimum spatter and puddle agitation.
Adjust Arc Length
with Peak Current
Note: In 100% CO2shielding gas applications the peak
current level should be set greater than in a corre-
sponding application using a gas blend with a high percentage of Argon. Longer initial arc lengths with 100%
CO2are required to reduce spatter.
BACKGROUND CURRENT
The Background Current provides the control for the
overall heat input to the weld. Adjusting this level too
high will cause a large droplet to form and globular type
transfer to occur resulting in increased spatter.
Adjusting this level to low will cause wire stubbing and
also poor wetting of the weld metal. This is similar to a
low voltage setting on a standard CV machine
Adjust Bead Shape
using Background Current
Note: Background Current levels for applications using
100% CO2
is less than similar procedures involving gas
blends with high percentages of Argon. This is a result
of the greater heat generated in the 100% CO
2 arc.
(100% CO2 is 35 volts/cm and 100% Argon is 20
volts/cm. 75% Argon, 25% CO
2 is about 24 volts/cm.
Contact
Tip to W
ork Distance
HOT START
The Hot Start control can be set to enhance establishing the arc and provide the capability of increasing the
heat at the start of the weld to compensate for a cold
work piece. Hot start adjusts the time that additional
current is applied during the starting of the arc. Refer to
“Operational Features and Controls” in this section
for a description of this control.
TAILOUT
The tail out provides additional heat without the molten
droplet becoming too large. Increase as necessary to
add “Heat” to the arc without increasing arc length.
(This will allow for faster travel speeds and produce
improved wetting). As tailout is increased, the peal
and/or background current is usually reduced.
WELDING ARC PERFORMANCE
For optimum spatter reduction, the arc should be concentrated on the puddle.
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
OPERATION
B-7 B-7
INVERTEC STT
WELDING PROCEDURES FOR STT II -
(Steel) Horizontal Fillet (See Table B.1 and B.2)
Table B.1
100% CO
2
Gas Shield (Set for Steel Mode)
Table B.2
75% CO
2
- 25% Ar Gas Shield (Set for Steel Mode)
(Stainless Steel) Horizontal Fillet
(See Table B.3 and B.4)
Table B.3
90% He, 7.5% Ar, 2.5% CO
2
Gas Shield (Set for Steel Mode)
Table B.4
98% Ar, 2% O
2
Gas Shield (Set for Stainless Steel Mode)
45°
END VIEW
75°
FRONT VIEW
DIRECTION
OF
TRAVEL
75°
TOP VIEW
DIRECTION
OF
TRAVEL
Plate Thickness “ (mm) 20 ga 14 ga 10 ga
(0.9) (2.0) (3.25)
Electrode size “ (mm) 0.035 0.045 0.045
(0.9) (1.1) (1.1)
WFS “/min (m/min) 100 100 170
(2.5) (2.5) (4.2)
Peak Current 220 260 280
Background Current 30 40 65
Tailout setting 3 7 5
Average Amperage 60 105 120
Travel Speed “/min 12 12 12
(m/min) (0.3) (0.3) (0.3)
Gas Flow cfh (L/min) 25 (12)
Electrical Stickout “ 1/4 - 3/8
(mm) (6.4 - 10)
Plate Thickness “ (mm) 20 ga 14 ga 10 ga
(0.9) (2.0) (3.25)
Electrode size “ (mm) 0.035 0.045 0.045
(0.9) (1.1) (1.1)
WFS “/min (m/min) 100 100 120
(2.5) (2.5) (3.0)
Peak Current 225 270 310
Background Current 40 65 70
Tailout setting 8 4 6
Average Amperage 70 110 130
Travel Speed “/min 12 12 12
(m/min) (0.3) (0.3) (0.3)
Gas Flow cfh (L/min) 25 (12)
Electrical Stickout “ 1/4 - 3/8
(mm) (6.4 - 10)
45°
END VIEW
75°
FRONT VIEW
DIRECTION
OF
TRAVEL
75°
TOP VIEW
DIRECTION
OF
TRAVEL
Plate Thickness “ (mm) 20 ga 14 ga 10 ga
(0.9) (2.0) (3.25)
Electrode size “ (mm) 0.035 0.045 0.045
(0.9) (1.1) (1.1)
WFS “/min (m/min) 100 130 170
(2.5) (3.3) (4.2)
Peak Current 165 210 250
Background Current 35 60 85
Tailout setting 7 7 4
Average Amperage 40 95 120
Travel Speed “/min 12 16 16
(m/min) (0.3) (0.4) (0.4)
Gas Flow cfh (L/min) 25 (12)
Electrical Stickout “ 1/4 - 3/8
(mm) (6.4 - 10)
Plate Thickness “ (mm) 20 ga 14 ga 10 ga
(0.9) (2.0) (3.25)
Electrode size “ (mm) 0.035 0.045 0.045
(0.9) (1.1) (1.1)
WFS “/min (m/min) 100 130 170
(2.5) (3.3) (4.2)
Peak Current 145 190 280
Background Current 45 95 95
Tailout setting 7 8 7
Average Amperage 60 120 150
Travel Speed “/min 12 12 12
(m/min) (0.3) (0.3) (0.3)
Gas Flow cfh (L/min) 25 (12)
Electrical Stickout “ 1/4 - 3/8
(mm) (6.4 - 10)
NOTES
B-8 B-8
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
TABLE OF CONTENTS
- ACCESSORIES -
Accessories...........................................................................................................................Section C
Options/Accessories ...................................................................................................................C-2
LN-742 Wire Feeder Connection Instructions.............................................................................C-3
Connection Diagram ...................................................................................................................C-4
Section C-1 Section C-1
INVERTEC STT
ACCESSORIES
C-2 C-2
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
STT control board to accept PEAK and BACKGROUND inputs on this connector rather than from
the front panel controls. If this short is removed, the
front panel controls will be active. By adding a switch
between pins “J” and “B” a “LOCAL/REMOTE” control switch can be created. (Switch open for “local”
and closed for “remote”)
3. For robotic control of the PEAK CURRENT, a 0 to
+10 volt DC signal is applied between pins “A” and
“G” with + applied to pin “G”. The BACKGROUND
CURRENT is controlled with a similar signal applied
between pins “A” and “C” with + applied to pin “C”.
In this application pins “J” and “B” must be shorted
as described in 2 above.
NOTE: These analog signals should be isolated
from the robot circuitry to prevent interference.
4. The trigger switch is connected between pins “D”
and “F”. These connections are in parallel with the
trigger switch from the wire feeder.
5. The digital meters for PEAK and BACKGROUND
currents will show preset values in both local and
remote operation.
OPTIONS / ACCESSORIES
K940 SENSE LEADS: These leads are used to accu-
rately sense arc voltage. One set is required for each
STT II power source. A 10 ft and 25 ft set are provided as standard with the machine. Additional sets are
available in 10 ft (K940-10), 25 ft (K940-25) and 50 ft
(K940-50) lengths.
K942-1 REMOTE CONTROL: Allows remote adjustment of Peak and Background Current settings.
REMOTE RECEPTACLE (For optional remote interface,
Connection to the STT-10 Wire Feeder or Robotic Control)
1. The 10 pin MS connector labeled “Remote Control”
located on the front panel of the STT is used for
remote control of the power source. Control for the
PEAK (PB pot) and BACKGROUND (BG pot) current along with the trigger switch is provide through
this connector.
2. Refer to figure C.1 below for details about the
remote receptacle (J38). Note that pins “J” and “B”
are shorted together This “short circuit” tells the
+ ARC
- ARC
1
2
3
4
VOLTAGE
SENSE
CONNECTION
J19
290
291
(+)
(-)
J
B
C
G
A
D
F
H
E
I
TRIGGER
GND
BG
PB
10K
10K
OPTIONAL
REMOTE
INTERFACE
223
7
J38
33C
1
2
3
4
J37
8
6
1
5
8
4
3
2
212C
43A
212B
32C
3
1
2
10
9
12
4
11
J38
REMOTE
PROTECTION BOARD
PORTION OF G3136 WIRING DIAGRAM
REFER TO ACTUAL DIAGRAM PASTED INSIDE YOUR MACHINE
N
ELECTRODE SENSE LEAD
290A
J39
WIRE
FEEDER
ACCESSORIES
C-3 C-3
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
LN-742 or STT-10 WIRE FEEDER
CONNECTION INSTRUCTIONS
The LN-742 or STT-10 is the recommended wire feeder for use with the Invertec STT II. Refer to the LN742 or STT-10 Operator Manual for Wire Feed
Operation. Refer to Figure C.2 or C.3 and follow the
instructions below to connect the LN-742 or STT-10.
1. Turn the Invertec STT II power off.
2. Connect the ARC SENSE LEAD MS connector to
the mating connector on STT II front panel.
3. Connect the electrode lead (Twist-Mate) to (+) output terminal on STT II.
4. Connect the other end of electrode lead (Step #3)
and the ARC SENSE LEAD (lead with ring lug, step
#2) together to the gun block on the LN 742.
5. Connect work lead between STT (-) terminal and the
work piece.
6. Connect the ARC SENSE LEAD “WORK” (lead with
alligator clip) to work piece.
NOTE: For best welding performance make this
connection as close as possible to the
welding arc.
7. Connect the wire feeder control cable between the
LN-742 or STT-10 and the 14-pin Wire Feeder
Receptacle on the STT II. For the STT-10 Wire
Feeder: Connect the second wire feeder control
cable between the STT-10 and the 10-pin Remote
Receptacle on the STT II.
M17657
ARC SENSE LEAD
’ELECT"
CONNECT ELECTRODE LEAD AND "ELECT"
ARC SENSE LEAD TOGETHER TO ELECTRODE
TERMINAL OF WIRE FEEDER.
ELECTRODE LEAD
Only qualified persons should install,
use or service this machine.
WIRE FEEDER
LN 742
LN7 GMA
LN9 GMA
NA5R
NA5
WARNING
ELECTRIC
SHOCK
CAN KILL
Turn off input power to the Welding
Power source using the disconnnect
switch at the fuse box before
connecting the wire feeder.
REMOTE RECEPTACLE
WORK
WORK LEAD
CONTROL, ELECTRODE, ARC SENSE "ELECT"
AND ARC SENSE "WORK" CABLES SHOULD
BE TAPED TOGETHER.
WIRE FEEDER
CONTROL CABLE
ARC SENSE LEAD "WORK"
(SHOULD BE LOCATED
AS CLOSE AS POSSIBLE
TO THE WELDING ARC.)
CRM after 6-10-96
FIGURE C.2 LN-742 to STT II CONNECTION
WARNING
ELECTRIC SHOCK can kill.
• Only qualified personnel should perform
this installation.
•Turn the input power OFF at the disconnect switch or fuse box before connecting
the wire feeder
C-4 C-4
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
ACCESSORIES
CONNECTION DIAGRAM - INVERTEC STT II
4-9-99
M17657-3
CABLES AND LEADS SHOULD
ELECTRODE LEAD
BE TAPED TOGETHER.
WORK
(SHOULD BE LOCATED
AS CLOSE AS POSSIBLE
FEEDER
REMOTE
REMOTE
ELECTRODE LEAD
TO THE WELDING ARC)
WORK LEAD
WIRE FEEDER
WIRE FEEDER CONTACT
ELECTRODE SENSE LEAD
IS BOLTED TOGETHER WITH
ELECTRODE LEAD ON THE
BLOCK
STT-10
WIRE FEEDER
WARNING
Turn off input power to the Welding
Power source using the disconnnect
switch at the fuse box before
connecting the wire feeder.
Only qualified persons should install,
ELECTRIC
use or service this machine.
SHOCK
CAN KILL
WIRE
ARC SENSE LEAD "WORK"
FIGURE C.3 STT-10 to STT II CONNECTION
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
Section D-1 Section D-1
INVERTEC STT
TABLE OF CONTENTS
-MAINTENANCE-
Maintenance .........................................................................................................................Section D
Input Filter Capacitor Discharge Procedure................................................................................D-2
Preventive Maintenance .............................................................................................................D-3
Major Component Locations.......................................................................................................D-4
MAINTENANCE
D-2 D-2
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
WARNING
Failure to follow this
capacitor discharge procedure can result in electric
shock.
INPUT FILTER CAPACITOR
DISCHARGE PROCEDURE
1. Turn off input power or disconnect input
power lines.
2. Remove hex head screws from side and
top of machine and remove wrap-around
machine cover.
3. Be careful not to make contact with the
capacitor terminals that are located in the
center of the Switch Boards.
4. Obtain a high resistance and high
wattage resistor (25-1000 ohms and 25
watts minimum). This resistor is not supplied with machine. NEVER USE A
SHORTING STRAP FOR THIS PROCEDURE.
5. Locate the two capacitor terminals (large
hex head cap screws) shown in Figure
D.1.
6. Use safety glasses, electrically insulated
gloves and insulated pliers. Hold body of
the resistor and connect resistor leads
across the two capacitor terminals. Hold
resistor in place for 10 seconds. DO NOT
TOUCH CAPACITOR TERMINALS WITH
YOUR BARE HANDS.
7. Repeat discharge procedure for capaci-
tor on other side of machine.
8. Check voltage across terminals of all
capacitors with a DC voltmeter. Polarity
of capacitor terminals is marked on PC
board above terminals. Voltage should be
zero. If any voltage remains, repeat this
capacitor discharge procedure.
FIGURE D.1 — LOCATION OF INPUT FILTER CAPACITOR TERMINALS.
MAINTENANCE
D-3 D-3
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
PREVENTIVE MAINTENANCE
1. Perform the following preventive maintenance procedures at least once every six
months. It is good practice to keep a preventive maintenance record; a record tag
attached to the machine works best.
2. Remove the machine wraparound cover
and perform the input filter capacitor discharge procedure (detailed at the beginning of this chapter).
3. Clean the inside of the machine with a
low pressure airstream. Be sure to clean
the following components thoroughly.
• Power Switch, Driver, Protection, and
Control printed circuit boards
• Power Switch
• Main Transformer
• Input Rectifier
• Heat Sink Fins
• Input Filter Capacitors
• Output Terminals
• Lower base compartment
4. Examine capacitors for leakage or oozing.
Replace if needed.
5. Examine wraparound cover for dents or
breakage. Repair as needed. Cover must
be kept in good condition to assure high
voltage parts are protected and correct
spacings are maintained.
6. Check electrical ground continuity. Using
an ohmmeter, measure resistance
between either output stud and an unpainted surface of the machine case. Meter
reading should be 500,000 ohms or more.
If meter reading is less than 500,000
ohms, check for electrical components that
are not properly insulated from the case.
Correct insulation if needed.
7. Replace machine cover and screws.
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
MAINTENANCE
D-4 D-4
INVERTEC STT
12
4
17
5
6
9
8
7
10
16
15
13
18
14
19
11
1
3
2
FIGURE D.2 – MAJOR COMPONENT LOCATIONS
1. BASE ASSEMBLY
2. REAR NAMEPLATE
3. RESISTORS
4. FAN SHROUD ASSEMBLY
5. PROTECTION PC BOARD
6. DRIVER PC BOARD
7. CONTROL BOX
8. CONTROL PC BOARD
9. BLEEDER RESISTORS
10. RECONNECT PANEL
11. IGBT OR DARLINGTON MODULE
12. WRAPAROUND ASSEMBLY
13. CASE FRONT ASSEMBLY
14. OUTPUT TERMINALS
15. OUTPUT CHOKE ASSEMBLY
16. TRANSFORMER ASSEMBLY
17. OUTPUT RECTIFIER ASSEMBLY
18. AUXILIARY TRANSFORMER
19. FET HEAT SINK ASSEMBLY
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
Section E-1 Section E-1
INVERTEC STT
Theory of Operation .............................................................................................................Section E
General Description ...............................................................................................................E-2
Input Voltage..........................................................................................................................E-2
Reconnect, Protection Board, Rectification and Precharge ..................................................E-3
Switch Boards........................................................................................................................E-4
Main Transformer, Output Rectification and Choke...............................................................E-5
Control Board, IGBT Drive and Module.................................................................................E-6
Power Board ..........................................................................................................................E-7
Remote Protection Board ......................................................................................................E-7
Field Effect Transistor (FET) Operation.................................................................................E-8
Pulse Width Modulation.........................................................................................................E-9
Minimum Output ..............................................................................................................E-9
Maximum Output .............................................................................................................E-9
Protective Circuits................................................................................................................E-10
Overload Protection.......................................................................................................E-10
Thermal Protection ........................................................................................................E-10
TABLE OF CONTENTS
-THEORY OF OPERATION SECTION-
POSITIVE
OUTPUT
TERMINAL
TERMINAL
OUTPUT
NEGATIVE
CONTROL BOARD
IGBT
DRIVER
BOARD
P
O
W
E
R
B
O
A
R
D
FAN
TRANS
T1
TRANS
T4
S
W
I
T
C
H
B
O
A
R
D
S
W
I
T
C
H
B
O
A
R
D
R
E
C
O
N
N
E
C
T
P
R
O
T
E
C
T
I
O
N
INPUT
RECTIFIER
LINE
SWITCH
CR1
CR2
B
O
A
R
D
D
R
I
V
E
R
B
O
A
R
D
PRE -
CHARGE
PRE -
CHARGE
CHOKE
CURRENT
SENSOR
IGBT
MODULE
1 OHM
PEAK
CURRENT
METER
BACK-
METER
PEAK
CURRENT
CONTROL
BACK-
CONTROL
HOT
START
CONTROL
WIRE
SIZE
SWITCH
WIRE
TYPE
SWITCH
VOLTAGE
SENSING
RECEPTACLE
REMOTE
CONTROL
RECEPTACLE
WIRE
RECEPTACL
E
FEEDER
R
E
M
O
T
E
P
R
O
T
E
C
T
I
O
N
B
O
A
R
D
CURRENT
TRANS
T3
MAIN
TRANSFORMER
T2
115
VAC
18
VAC
2
4
V
A
C
"A"
LEAD
15VDC
T
H
E
R
M
O
S
T
A
T
CURRENT FEEDBACK
42VAC
VOLTAGE FEEDBACK
10VAC AND 6VAC
D
R
I
V
E
S
I
G
N
A
L
36VAC
GUN TRIGGER
LESS THAN 1VDC
PWM SIGNAL
PULSE TRANSFORMER SIGNAL
GROUND
GROUND
FET
FET
FET
FET
CAP
CAP
TAILOUT
CONTROL
(STT II ONLY)
FIGURE E.1 – INVERTEC STT
GENERAL DESCRIPTION
The Invertec STT is a 225 ampere, inverter based, arc
welding power supply specifically designed for the
Surface Tension Transfer (STT) welding process. It
cannot be classified as either a constant current (CC)
or a constant voltage (CV) machine. The STT produces current of a desired waveform to reduce spatter
and fumes. The STT process is optimized for short circuit GMAW welding only.
INPUT VOLTAGE
The Invertec STT can be connected for a variety of
three-phase voltages. The initial input power is applied
to the STT through a line switch located on the front of
the machine. The AC input voltage is applied to the
input rectifier and the T1 auxiliary transformer. The T1
transformer develops the appropriate AC voltages to
operate the cooling fan, the power and control boards.
The T1 transformer also supplies primary voltage to the
T4 auxiliary transformer as well as 42 VAC to an external wire feeder. The T4 transformer supplies power to
the IGBT drive board and the control board.
THEORY OF OPERATION
E-2 E-2
INVERTEC STT
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
FIGURE E.2 – INPUT VOLTAGE
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.
POSITIVE
OUTPUT
TERMINAL
TERMINAL
OUTPUT
NEGATIVE
CONTROL BOARD
IGBT
DRIVER
BOARD
P
O
W
E
R
B
O
A
R
D
FAN
TRANS
T1
TRANS
T4
S
W
I
T
C
H
B
O
A
R
D
S
W
I
T
C
H
B
O
A
R
D
R
E
C
O
N
N
E
C
T
P
R
O
T
E
C
T
I
O
N
INPUT
RECTIFIER
LINE
SWITCH
CR1
CR2
B
O
A
R
D
D
R
I
V
E
R
B
O
A
R
D
PRE -
CHARGE
PRE -
CHARGE
CHOKE
CURRENT
SENSOR
IGBT
MODULE
1 OHM
PEAK
CURRENT
METER
BACK-
METER
PEAK
CURRENT
CONTROL
BACK-
CONTROL
HOT
START
CONTROL
WIRE
SIZE
SWITCH
WIRE
TYPE
SWITCH
VOLTAGE
SENSING
RECEPTACLE
REMOTE
CONTROL
RECEPTACLE
WIRE
RECEPTACL
E
FEEDER
R
E
M
O
T
E
P
R
O
T
E
C
T
I
O
N
B
O
A
R
D
CURRENT
TRANS
T3
MAIN
TRANSFORMER
T2
115
VAC
18
VAC
2
4
V
A
C
"A"
LEAD
15VDC
T
H
E
R
M
O
S
T
A
T
CURRENT FEEDBACK
42VAC
VOLTAGE FEEDBACK
10VAC AND 6VAC
D
R
I
V
E
S
I
G
N
A
L
36VAC
GUN TRIGGER
LESS THAN 1VDC
PWM SIGNAL
PULSE TRANSFORMER SIGNAL
GROUND
GROUND
FET
FET
FET
FET
CAP
CAP
TAILOUT
CONTROL
(STT II ONLY)
Loading...