HTP Invertig 301 User manual

Invertig™301/400
180 Joey Drive
Elk Grove Village, IL 60007-1304
Ph.: [phone] Fax: [phone]
Email: [e-mail]
Web: www.usaweld.com
Scan QR Code
for Video
Playlist

3
INDEX
1) FOREWORD
4
2) WARRANTY
4
3) SAFETY SUGGESTIONS
5-7
4) SPECIFICATIONS
8
5) ELECTRICAL CONNECTION
9
6) FRONT PANEL CONNECTIONS
10
7) REAR PANEL CONNECTIONS
11
8) EXPLANATIONS
12-20
a) Invertig 301 vs. Invertig 400
12
b) Torches
12
c) Wave Forms
12-13
d) Nominal vs. Average Amps
13
e) AC Balance
14
f) AC Frequency
14
g) Asymmetric Arc
14
h) Pulse in DC TIG
14-15
i) Pulse in AC TIG (Square Wave Only)
15
j) Pulse in Stick (Square Wave Only)
16-18
k) Hot-Start for Stick
18
l) Hot-Start for TIG
18
m) Hot-Start vs. Starting Amps in TIG
18
n) HF-, Lift-, & Scratch-Start
18-19
o) Pipe Mode
19
p) Amperage Limitation in Single-Phase
19
q) Smart Cooler Operation & Control
20
9) FRONT PANEL CONTROLS
20
10) HOW TO WELD—STEP BY STEP
21-32
a) STICK
21-23
b) TIG 2T
23-28
c) TIG 4T
29-30
d) TIG SPOT
30
e) TIG RESET
30-32
11) JOB MODE
32
12) OVER-TEMP (OVER-HEAT) & DUTY-CYCLE
33
13) EXPLODED VIEW & PARTS LIST
34-37
14) WIRING DIAGRAM
38-39
15) GLOSSARY
40

4
1) FOREWORD
Thank you for purchasing an HTP America® Invertig™301/400—our advanced, multi-process TIG welder. The Invertig
301/400 is a versatile, high-quality, and feature-rich machine that offers pulse features in every welding process. With the
Invertig 301/400 you can run the following processes: SMAW (Stick), SMAW-P (pulsed Stick), GTAW (TIG), and GTAW-P
(pulsed TIG). All four processes offer both AC and DC options.
In addition, the machines feature a Pipe welding mode, which, when selected, deactivates the foot pedal and the
internal gas solenoid so an air-cooled torch with a valve can be used to simulate welding in the field off an engine drive
in TIG or in Stick mode. The Pipe mode is DC only.
In the AC TIG mode, the following wave forms are available: square wave, soft square wave, and triangular wave. The
Invertig 301 is a single-phase only machine, it runs on 208 to 240V. The Invertig 400 offers the ability to run on single-
phase power, from 208 to 240V, or on 3-phase power, from 200 to 575V. For maximum performance (power output
and duty-cycle) we recommend that you connect the machine to 3-phase power. The manual describes the Invertig
301/400 power source and its features and capabilities.
For crisp arc starts and excellent arc stability we also recommend the use of 2% ceriated (U.S. Color Code: Gray;
European Color Code: Orange) tungsten electrodes as our inverter is designed to work best with them.
2) WARRANTY
It is expressly agreed that there are no warranties, expressed or implied, made by either the Salesman, Dealer, or HTP
America, Inc. on products or parts furnished hereunder, except the Manufacturer’s Warranty against defective
materials or workmanship as follows:
HTP America, Inc. warrants each new welding machine to be free from defects in material and workmanship under
normal use and service for Three (3) Years after delivery to the original purchaser. HTP America, Inc. will repair or
replace, at its factory, any part or parts thereof. Products should be returned to HTP America, Inc., with transportation
charges prepaid, and which its examination shall disclose to its satisfaction to have been thus defective. This warranty
being in lieu of all other warranties, expressed or implied, and all other obligations or liabilities on its part and it
neither assumes nor authorizes any person to assume for it any liability in connection with the sale of its machines.
This warranty shall not apply to any welding machine which has been repaired or altered by unauthorized service
departments in any way so as, in the judgment of HTP America, Inc., to affect its stability and reliability, nor which has
been subjected to misuse, negligence, or accident.
HTP America, Inc. shall not be liable in any event, unless HTP America, Inc. receives notice of alleged breach of
warranty, actual or constructed, specifying the claimed defect within not more than Thirty (30) Days after discovery.
HTP America, Inc. has reserved the right to make changes in design or add any improvements to its products, at any
time, without incurring any obligation to install the same on equipment.
This warranty is void unless the warranty card is sent to HTP America, Inc. within Fifteen (15) Business Days from the
date of purchase.
EXCLUSIONS TO WARRANTY:
1) TIG welding torches are warranted for a period of Ninety (90) Days against defects in material and workmanship.
2) Tungsten electrodes, collet bodies, collets, and gas lenses are consumable items, WHICH CARRY NO WARRANTY.
3) Artic Chill and Smart Water Coolers come with an Eighteen (18) Month Warranty.
Note: This warranty is to the original purchaser only. The warranty can be transferred to another owner, with
HTP’s approval, for a warranty transfer fee. HTP America, Inc. must be notified within Fourteen (14) Days of the sale
and must be provided with the contact information of the original owner, the contact information of the new owner,
and the serial number of the machine.

5
3) SAFETY SUGGESTIONS
It is forbidden for people with PACEMAKERS to use or come near the machine. When welding near sensitive
electronics, for example in hospitals or assisted living homes or around computers or computer control
modules in vehicles, we STRONGLY recommend turning off HF (high-frequency arc start). Even an AC arc on a
modern inverter can be ignited in lift-arc mode! HF travels long distances, 10 to 20 feet are very common in
some instances, and HF can interfere with electronics in neighboring buildings if they are on the same
transformer! Unlike regular welding currents, that travel the path of least resistance, HF is unpredictable.
Electric arc welding produces ultra-violet rays, which are harmful to skin and eyes. Ultra-violet radiation can
penetrate lightweight clothing, reflect from light-colored surfaces, and burn the skin and eyes.
•Wear a heavy, pocket-less, long-sleeved shirt, cuff-less trousers, and high-topped work shoes.
•Wear a full-faced welding helmet with a number ten or darker lens and a cap.
Electric arc welding produces flying sparks and hot material, which can cause fire.
•To avoid fire, do not weld on wood, plastic tile, or carpeted floors. Concrete or masonry floors are safest.
•Do not weld on pressurized containers.
•Do not weld on drums, barrels, tanks, or other containers until they have been cleared and cleaned as described in
AWS Standard A6.01.
•Do not wear flammable materials.
•Wear non-oily/non-greasy, flameproof welding gloves; the oil or grease on the gloves may ignite.
•Avoid having any type of fuel, such as cigarette lighters or matches, on your person as you weld.
•Ensure that there is a fire extinguisher in the welding area.
Electric arc welding produces toxic fumes.
•Provide adequate ventilation in the welding area at all times.
•Do not weld on galvanized zinc, cadmium, or lead beryllium materials unless you are POSITIVE that sufficient
ventilation is provided. These materials produce toxic fumes.
•Do no weld in areas close to degreasing or spraying operations. Chlorinated hydrocarbon vapors may react with
the ultra-violet rays and form highly toxic phosphate gas.
•If you develop eye, nose, or throat irritation during welding, stop welding immediately. This is an indication that
ventilation is not adequate. Do not continue to weld until ventilation is improved.
ELECTRIC SHOCK CAN KILL.
Exposed, electrically hot conductors, other bare metal in the welding circuit, or ungrounded, electrically hot equipment
can fatally shock a person whose body becomes a conductor. Do not stand, sit, lie, lean on, or touch a wet surface when
welding.
•Disconnect the power supply before working on the welding machine.
•Do not work with deteriorated or damaged cables.
•Frequently inspect cables for wear, cracks, and damage. Replace those with excessively worn insulation to avoid a
possible lethal shock from bared cable.
•Do not touch bare electrical parts.
•Ensure that all of the panels covering the welding machine are firmly secured in place when the machine is
connected to the power supply.
•Insulate yourself from the workbench and from the floor (ground); use insulating footwear and gloves.
•Keep gloves, footwear, clothes, the work area, and the welding equipment clean and dry.
•Check the machine power cable frequently; the power cable must be free from damage to the insulation. BARE
CABLES ARE DANGEROUS. Do not use the machine if the power cable is damaged; a damaged power cable must be
replaced immediately.
•If it is necessary to open the machine, first disconnect the power supply and then wait Five (5) Minutes to allow the
capacitors to discharge. Failure to take this precaution may expose you to the dangerous risk of electric shock.

6
Noise can damage your hearing. Protect yourself suitably to avoid hearing damage.
The welding arc can cause burns. Keep the tip of the welding gun/torch far from your body and from other
persons.
For more information, refer to the following standards and comply as applicable.
) ANSI Standard Z49.1 SAFETY IN WELDING AND CUTTING, obtainable from the American National Standards
Institute, 1430 Broadway, New York, NY 10018.
) ANSI Standard Z87.1 SAFE PRACTICE FOR OCCUPATIONAL AND EDUCATIONAL EYE AND FACE PROTECTION,
obtainable from the American National Standards Institute, 1430 Broadway, New York, NY 10018.
) AWS Standard A6.0 WELDING AND CUTTING CONTAINERS WHICH HAVE HELD COMBUSTIBLES, obtainable from
the American Welding Society, 2051 NW 7th St., Miami, FL 33125.
4) NFPA Standard 51 OXYGEN-FUEL GAS SYSTEMS FOR WELDING AND CUTTING, obtainable from the National Fire
Protection Association, 470 Atlantic Ave., Boston, MA 02210.
) NFPA Standard 51B CUTTING AND WELDING PROCESSES, obtainable from the National Fire Protection
Association, 470 Atlantic Ave., Boston, MA 02210.
) CGA Pamphlet P-1 SAFE HANDLING OF COMPRESSED GASES IN CYLINDERS, obtainable from the Compressed Gas
Association, 500 Fifth Ave., New York, NY 10036.
) OSHA Standard 29 CFR, Part 1910, Subpart Q, WELDING, CUTTING, AND BRAZING.

7
Fig. 1

8
0 Amps
ps
ps
.0
0
0.0
0.0
0
9
.0
0.0
99.9
0
0
4) SPECIFICATIONS
Invertig 301 AC/DC
Invertig 400 AC/DC
Input Voltage
230V (208 to 240V) Single Phase
Single-Phase: 230V (208 to 240V)
3-Phase: 200 to 575V
Welding Current Single-Phase
4 to 300 Amps
4 to 350 Amps
Welding Current 3-Phase
NA
4 to 400 Amps
Single-Phase Rated Output
40% @ 300 Amps
35% @ 350 Amps
230V Single-Phase Input Amps @ Rated Load
54 Amps
50 Amps
3-Phase Rated Output
NA
30% @ 400 Amps
3-Phase Input Amps @ Rated Load
NA
230V = 36 Amps
400V = 21 Amps
460V = 17.6 Amps
500V = 16.8 Amps
Welding Modes
STICK
TIG 2T
TIG 4T
TIG SPOT
TIG RESET
STICK
TIG 2T
TIG 4T
TIG SPOT
TIG RESET
Programmable Memories
30
30
Asymmetric AC
Yes
Yes
AC Frequency (Hz)
20 to 400 (Up to 100 Amps)
20 to 200 (Over 100 Amps)
20 to 400 (Up to 100 Amps)
20 to 200 (Over 100 Amps)
AC Balance (%)
10 to 90
10 to 90
Pre-Flow (Seconds)
0.1 to 5.0
0.1 to 5.0
Post-Flow (Seconds)
0.1 to 99.9
0.1 to 99.9
Initial Amps (%)
10 to 90
10 to 90
Final Amps (%)
10 to 90
10 to 90
Slope Up (Seconds)
0.1 to 10.0
0.1 to 10.0
Slope Down (Seconds)
0.1 to 10.0
0.1 to 10.0
Spot Time (Seconds)
0.1 to 10.0
0.1 to 10.0
Hot-Start (%)
0 to 50
0 to 50
Arc-Force (%)
0 to 500
0 to 500
Wave Forms
Square
Soft Square
Triangular
Square
Soft Square
Triangular
EN Amperage (%)
10 to 99
10 to 99
EP Amperage (%)
10 to 99
10 to 99
Duty-Cycle Single-Phase TIG
40% @ 300 Amps
60% @ 250 Amps
100% @ 200 Amps
35% @ 350 Amps
60% @ 250 Amps
100% @ 200 Amps
Duty-Cycle 3-Phase TIG
NA
30% @ 400 Amps
60% @ 340 Amps
100% @ 300 Amps
Duty-Cycle Single-Phase Stick
35% @ 260 Amps
60% @ 200 Amps
100% @ 180 Amps
35% @ 260 Amps
60% @ 200 Amps
100% @ 180 Amps
Duty-Cycle 3-Phase Stick
NA
35% @ 300 Amps
60% @ 240 Amps
100% @ 200 Amps
Dimensions
26-1/2” L x 12-1/4” W x 17-1/2” H
26-1/2” L x 12-1/4” W x 17-1/2” H
Weight
112 Lbs.
121 Lbs.
Pulse Parameters
Pulses/Second (PPS) Stick AC & DC
Pulses/Second (PPS) TIG AC
Pulses/Second (PPS) TIG DC
Peak Time (%)
Background Amps (%)
0.4 to 5.0
0.4 to 20.0
0.4 to 999.9
10 to 90
10 to 90
0.4 to 5.0
0.4 to 20.0
0.4 to 999.9
10 to 90
10 to 90

9
5) ELECTRICAL CONNECTION
Your Invertig 301/400 operates on single-phase, 230 volt power (208 to 240 volt). The Invertig 301 draws 54 amps
out of the wall when operating at max output (300 amps). The Invertig 400 draws 50 amps out of the wall when
operating at a welding output of 350 amps (the max output of the Invertig 400 on single-phase).
We ship your Invertig 301 with a NEMA 6-50P single phase plug. We ship your Invertig 400 without a plug since we
don’t know if you will run your machine on single or 3-phase power or what your electrical outlet looks like.
To connect the machine to single-phase power, use power cord’s (Fig. 3, T) black wire and white wire as your two hot
wires. Then, use the green wire (or green/yellow wire) as your ground. The red wire is NOT used in single-phase
operation and should be trimmed and wrapped in electrical tape. During operation of the machine, the red wire may
become electrically hot.
NOTE: The Invertig 400 does not include or require a common or neutral wire—even though one of the wires is
white, it is meant to be connected to a hot leg (do NOT connect it to the common).
You can run your Invertig 400 on 200 to 575 volt, 3-phase power. The power draw on 480 volt, 3-phase power is 17.2
amps.
Once you decide to run on single-phase or 3-phase input power and install the correct plug (or wire the machine to a
disconnect), turn the main switch (Fig. 3, S) on (Position 1). As a normal part of the boot up process, “PF0” appears in
the Voltage display (red numeric; above LCD). PF0 indicates that the PFC (Power Factor Correction; for an explanation
of PFC, please see the glossary at the end of the manual) sees 0, which means the PFC has not yet figured out the input
voltage nor configured itself accordingly. As the machine boots up, please be patient. The boot up process only takes
about 10 seconds. Please do not tap the foot pedal or attempt to adjust the front panel LCD until your machine boots up
completely. Failure to allow the machine to fully boot up could render the machine temporarily unusable. Wait times
from ten minutes to one hour may be needed to reset the welding machine.
If you would like to operate your Invertig on a generator, the generator can be single-phase or 3-phase. The advanced
design of the Invertig lets the machine operate on most generators. However, the Invertig is not compatible with all
generators. To ensure proper operation of your Invertig 301/400 on a generator, the generator must provide a
stable 50 to 60Hz AC frequency with low noise levels. If your generator does NOT meet the requirements, the Invertig
will likely not work with the generator. However, due to sophisticated electronics in the Invertig, it is highly unlikely to
damage the machine by plugging it into a non-suitable generator.
In order to operate the Invertig 301 or 400 on a single-phase generator, the generator needs a minimum of 12000 watts
(12000 watts must be the continuous rating or running watts rating of the generator, NOT the peak rating or starting
watts rating of the generator). In order to get the full 400 amps on 3-phase with the Invertig 400, you need a
15000 watt or better generator.

10
6) FRONT PANEL CONNECTIONS
Fig. 2
Z—Negative Output Receptacle
When TIG welding, connect the TIG torch to the negative output receptacle to weld Electrode Negative (EN; with the
torch negative and the work positive). When using your Invertig to TIG weld, all work will be done in EN. When Stick
welding in Direct Current Electrode Negative (DCEN), plug the optional electrode holder into the negative output
receptacle. When Stick welding in Direct Current Electrode Positive (DCEP), plug the ground cable into the negative
output receptacle.
To install a cable into the negative output receptacle, insert the male end of the cable into the negative output
receptacle and twist clockwise until snug. It is important that the cable is snug; a loose connection generates heat,
damages the machine, and causes weld quality issues.
U—Gas Output Connection
Connect the gas fitting from the TIG torch to the gas output connection. The gas output is controlled by the solenoid
valve, which is mounted inside the machine. The gas fitting is 1/4” BSP. NOTE: 1/4” BSP is a 19 TPI thread and is
NOT interchangeable with 1/4” NPT (regular pipe thread), which is an 18 TPI thread!
N—Trigger Connector
Typically not used as the Y connector also contains trigger wires.
Y—14-Pin Remote Control Connection
Used to connect your remote amperage control or momentary switch to your Invertig. Insert the connector into the
machine and twist the lock ring until snug. We find it easier to install the remote control connection prior to installing
the ground cable.
W—Positive Output Receptacle
When TIG welding, connect the ground cable to the positive output receptacle to weld in straight polarity (with the
torch negative and the work positive). When Stick welding in Direct Current Electrode Negative (DCEN), plug the
ground cable into the positive output receptacle, and when Stick welding in Direct Current Electrode Positive (DCEP),
plug the electrode holder into the positive output receptacle.
To install a cable into the positive output receptacle, insert the male end of the cable into the positive output receptacle
and twist clockwise until snug. It is important that the cable is snug; a loose connection generates heat, damages the
machine, and causes weld quality issues.

11
7) REAR PANEL CONNECTIONS
Fig. 3
P—Smart Water-Cooler Connection
Used to connect the 7-pin cable for the smart water-cooler. The connection extinguishes the arc if you lose coolant flow
and starts the pump when you initiate an arc.
M—Serial Number Tag
Contains the serial number of your Invertig 301/400. The serial number consists of two letters and six numbers.
S—On/Off Switch
The switch turns your Invertig 301/400 on and off. Set the switch to position 0 for off, and set the switch to position 1
for on.
O—Smart Water-Cooler Power Connection
If you purchased an HTP America smart water-cooler, this is where the cooler picks up the voltage to operate (only
available on HTP machines and with HTP smart water-coolers).
T—Input Power Cord Q—
Shield Gas Inlet Connection
Attach the gas hose from your flowmeter to the gas inlet connection. The gas fitting is 1/4” BSP. NOTE: 1/4” BSP is a 19
TPI thread and is NOT interchangeable with 1/4” NPT (regular pipe thread), which is an 18 TPI thread!

8) EXPLANATIONS
a) Invertig 301 vs. Invertig 400
The Invertig 301 is a 300 amp AC/DC TIG welder with single-phase capacity only. The Invertig 301 runs on 208 to 240
volt input power, and features the same functions as the Invertig 400 but has less maximum output and a slightly lower
duty-cycle. We offer the Invertig 301 in 3 different packages. The air cooled Invertig 301 comes paired with a Heavy
Hitter 26 series flex head and CK Worldwide 26 series super flex cable, rated for 350 amps. The Invertig 301 offers two
water cooled packages, the Arctic Chill water-cooler or Smart water cooler and comes with a CK Worldwide 23 series
super flex TIG welding torch. For the Invertig 301, we offer hard-wired foot pedals, hand controls (rotary or slider),
momentary switches, as well as a wireless foot pedal. The Invertig 301 is also compatible with the TigControl.com
TigButton™.
The Invertig 400 is a 400 amp AC/DC TIG welder with single or 3-phase capability. The Invertig 400 runs on 208 to 240
volt input power on single-phase, with a max power output of 350 amps, and runs on 200 to 575 volt input power on 3-
phase, with a max output of 400 amps. To take full advantage of the Invertig 400’s max power output and duty-cycle,
we recommend 3-phase input power as single-phase input power limits max output and duty-cycle. Typically, we pair
the Invertig 400 with a smart, multi-voltage water-cooler that is integrated into the cart, and a CK Trim Line 18 TIG
welding torch (other torches available by request). For the Invertig 400, we offer hard-wired foot pedals, hand controls
(rotary or slider), momentary switches, as well as a wireless foot pedal.
b) Torches
A variety of air- and water-cooled torches can be used with our Invertig machines. However, all air–and water-cooled
torches have their limits! Running past the limit results in torch damage, which is not covered under warranty. We
offer the following torches (the amp ratings provided represent the max amp rating, based on 100% duty-cycle, for
each torch):
CK9 Air-Cooled Torch (Rated at 125 amps)
CK17 Air-Cooled Torch (Rated at 150 amps)
CK26 Air-Cooled Torch (Rated at 200 amps; uses the same consumables as the CK17 torch)
CK20 Water-Cooled Torch (Rated at 250 amps; uses the same consumables as the CK9 torch)
CK230 Water-Cooled Torch (Rated at 300 amps; uses the same consumables as the CK9 and CK20 torch)
CK TL18 Water-Cooled Torch (Rated at 350 amps; uses the same consumables as the CK17 and CK26 torch)
Heavy Hitter 350 Torch Head (Rated at 350 amps; uses the same consumables as the CK17 and CK26 torch)
All torches are available in 12’ and 25’ lengths.
NOTE: The Invertig 400 offers the option to limit the max output of the machine to 300 amps so you can safely
use a CK230 torch.
c) Wave Forms
All wave forms are available in AC TIG and Stick welding mode. Pulse can only be used with square wave.
Square Wave: The standard wave form for all modern inverter TIG welding
machines. The square wave offers excellent power, arc control, and bead
appearance. A good choice, all around, for aluminum welding. When in use,
some operators may perceive the square wave sound as loud and unpleasant.
However, many operators prefer to use a square wave due to its superior
performance and features, such as the ability to run pulse.
When Soft AC and Triangular AC are turned off (Fig. 4), the machine is in
square wave.
12 Fig. 4

13
Soft Square Wave: The soft square wave provides a more sinus like wave form, which allows for a softer arc and a
more fluid weld puddle, and it does so while creating significantly less noise. The SOFT symbol on the right-hand side of
the LCD above the 3-phase symbol (Fig. 5) indicates that Soft AC is selected and active. Also referred to as a modified
square wave. Pulse functions are unavailable in Soft AC.
Fig. 5
Triangular Wave: The triangular wave form allows you to reach maximum peak current while dramatically
reducing the overall heat input. When using a triangular wave form, the machine can be configured to show either the
maximum (peak) amperage or the overall (actual) amperage welding output on the LCD. The Amperage display (red
numeric; above LCD) always shows the max (nominal/peak) amperage. Rapid formation of melting points reduces the
overall welding time, which, in turn, alleviates distortion—especially when welding thin material. The triangular wave
creates a fast freezing puddle, which results in superior control and heat input management. When in use, the triangular
wave function symbol appears on the main screen of the LCD. The TRI symbol on the right-hand side of the LCD above
the 3-phase symbol (Fig. 6) indicates that Triangular AC is selected and active. Pulse functions are unavailable in
Triangular AC.
Fig. 6
d) Nominal vs. Average Amps
AC welding contains a lot of variables compared to DC welding. Those variables influence, in some cases massively, the
welding arc and power output. Very high frequencies result in lower amperage outputs. Since the arc does not spend as
much time on one side of the zero line, and changes directions very fast, the overall heat input is naturally reduced. This
means the max amperage does not match the average amperage. For example, you can set the max amperage to 200
amps, but the average amperage you hit while welding may only be 180 amps. While not welding, the machine shows, in
the Amperage display (red numeric; above LCD), the max amperage that you can achieve with the foot pedal completely
depressed, and, in the LCD, the machine displays the starting amps. While welding, the Amperage display shows the
nominal amperage (what the foot pedal is currently depressed to), and the LCD shows the same or the average (actual)
amperage (your choice). The difference is more significant when using a soft square wave form and most significant
when using a triangular wave form. When using a triangular wave form, a max setting of 400 amps could result in an
average of roughly 260 amps due to the wave form and shape.
Fig. 7; By pressing button D (Fig. 11) while welding, you can toggle between
displaying the average amperage and the max amperage.

14
e) AC Balance
Balance refers to the time the arc spends above or, in the case of HTP machines, below the zero line. What does that
mean? Imagine you weld AC and you set your frequency not to 100Hz but to 1Hz (1Hz used for the purpose of easy
demonstration; the frequency of the Invertig 301/400 cannot be set any lower than 20Hz). Set at 50% balance, your
current would come out of the material and go into the torch (your electrode positive (EP) part) for 0.5 seconds. For the
next 0.5 seconds, your current would come out of the torch and go into the material. Let’s say you weld at 100 amps. For
0.5 seconds, you will see 100 amps come out of the material and go into the torch, and for the following 0.5 seconds, you
will see 100 amps come out of the torch and go into the material. Do you need 0.5 seconds of electrode positive (EP)/
cleaning/breaking open of the oxide layer? No, most likely not—that is why you typically don’t weld with a 50% balance.
Do you want more electrode negative (EN)/penetration and to put heat into the material you are welding (rather than
the torch)? Yes, absolutely. Most people consider an EN balance between 60 and 80% the sweet spot. With balance set
too low, the tungsten balls, and with the balance set too high, the weld bead turns gray, flat, and dull. You may even see
some peppering in the weld along with insufficient cleaning of the oxide layer. On the Invertig 400, you can adjust the
balance from 10 to 90%.
f) AC Frequency
AC frequency does two things, mainly. First, AC frequency focuses the arc. Higher frequencies feature a more focused arc
and a narrower frost line, which works really well on thin material. On thick material, higher frequencies tend to make it
hard to join two pieces of material, as the focused arc wants to cling to only one piece and not join it to the other piece.
Second, AC frequency affects heat input. As previously discussed in 7d, higher frequencies result in a lower overall heat
input. Lower frequencies result in a higher overall heat input. In other words, thin material prefers higher frequencies
(this is why the Invertig offers an adjustment range from 20 to 400Hz when operating at an output under 100 amps),
and thicker material prefers lower frequencies. Although the adjustment above 100 amps lets you choose AC
frequencies from 20 to 200Hz, at a material thickness of 1/4”, 1/2”, or even higher, it is not uncommon to see
frequencies of 50Hz or less be used on a regular basis for best results.
g) Asymmetric Arc
Asymmetric arc determines the intensity of the current rather than the time (the balance function determines the time).
Going back to our previously described example weld with 1Hz AC and a 50% balance at 100 amps, this time limiting the
EP to 50%, you now weld for 0.5 seconds at 50 amps (50% of 100 amps) of EP/cleaning/breaking open the oxide layer,
and then you weld for 0.5 seconds with 100 amps of EN/penetration and heating of the material (rather than the torch).
Does asymmetric arc do the same thing as balance? Sort of, but not really. If you turn asymmetric arc off, set
your frequency to 1Hz, and set your balance to 75% (EN), you weld for 0.25 seconds with 100 amps. (Is that the same as
welding 0.5 seconds with 50 amps? No, but it starts to get into a similar ballpark). But NOW you have 0.75 seconds of
EN, which gives you much better penetration than 0.5 seconds
So, is balance better than asymmetric arc? No, and although it is very similar, it is still different. Asymmetric arc
allows you to control the size of the cleaning action line, or the frost line, much better (the cleaning action line is
typically related more so to frequency but small adjustments to the asymmetric arc can make a big difference in certain
situations) and also the shininess of the finished weld bead. Often, high balance settings, while providing a lot of
penetration, create a rather gray, flat, and dull weld bead, even with 4000 series filler rod, where some asymmetric arc
really helps with making the weld bead shinier.
Typically, you cannot find literature, videos, or any other online advice on setting asymmetric arc. Your asymmetric arc
setting depends a lot on your base metal; for example, 6061 welds differently than 5052, and 5052 welds differently
than 3003. Your asymmetric arc setting also depends on your specific application and variables such as size,
temperature, cleanliness, filler rod, etc.
You can only limit either EN or EP, not both at the same time, and the limit range spans from 10 to 99% (100% would be
turning asymmetric arc off). Whichever value you do not limit is set at 100% (but this is not shown in the LCD).
h) Pulse in DC TIG
You typically use the DC pulse function to reduce the heat input when welding to prevent distortion or excessive
discoloring of the base metal. The Amperage display (red numeric; above LCD) shows the maximum amperage, and

15
you set the background amperage and the peak time (pulse-on time or duty) based on that maximum amperage. You set
both the background amperage and the peak time as a percentage of the maximum amperage. Peak time refers to the
peak pulse current number. The actual duration of the peak time, in seconds or in fractions of a second, depends on the
third variable—the pulse frequency. The pulse frequency determines the speed, for lack of a better word, of the time it
takes to switch between the higher and the lower amperage. There are two schools of thought:
 Use low-speed pulse frequencies between 0.5 and 2.0 PPS (pulses per second or Hz) to create a ripple effect in the
weld bead. The pulsing can easily be seen by the human eye. When using low-speed pulse frequencies, you typically
will not experience any interference or other technical difficulties with either fixed shade or auto-darkening welding
helmets.
 Use high-speed pulse frequencies between 25 and 100 PPS to create a smooth weld bead, much like DC TIG without
pulse. The pulsing usually cannot be seen by the human eye. You typically use high-speed pulse frequencies when
welding stainless or mild steel out of position, when heat affected zones need to be kept to a minimum, or when
warpage or distortion of parts are a concern. When using auto-darkening welding helmets, depending on the
frequency of the cartridge in the welding helmet and the frequency you set the machine to, there may be a very
narrow band of specific frequencies where interferences are possible. Whether interferences happen at all, or at
what frequency the interferences occur at, depends on the welding helmet you use (make, model, etc.); we cannot
predict who will experience interferences. If, when welding, you notice flickering, change your frequency by +/- 20
PPS and try again.
For most applications, we recommend setting the background amperage to 25% and the peak time (pulse-on time or
duty) to 25%. Example: You set your max amperage to 100 amps, your background amperage to 25%, and your peak
time to 25%. For 25% of the time, you weld at 100 amps, and for 75% of the time, you weld at 25 amps.
Using these settings during a low-speed pulse application (with the right torch movement and either no filler or while
using a lay wire technique) allows you to produce nice ripples. Using these settings during a high-speed pulse
application allows you to achieve penetration close to what 100 amps of straight DC gives, but with significantly lower
heat input and a much more controllable puddle. Even though you only reach 100 amps 25% of the time, and 25 amps
75% of the time, in a high-speed pulse scenario it is NOT safe to assume that the first quarter at 100 amps and the
second through fourth quarters at 25 amps equal 43.75 amps of overall heat input (100 + 25 + 25+ 25 = 175/4 = 43.75).
While the math does not hold true in high-speed pulse applications, the math comes a lot closer in low-speed pulse
applications. In a high-speed pulse application, at a 25 PPS pulse frequency setting, you introduce 100 amps into the
base material 25 times per second, and at a 50 PPS pulse frequency setting, you introduce 100 amps into the base
material 50 times per second. Even though this occurs for a short or a very short period of time, the time between the
100 amp bursts is not long enough to let the material really cool down to an average of 44 amps of heat input.
Nevertheless, a high-speed pulse application is significantly cooler than just DC TIG.
The strongest effects and the best results occur when you set the difference between the peak amperage and the
background amperage rather high. With the Invertig 301/400, you can adjust the pulse frequency from 0.4 to 999.9 PPS,
the background amps from 10 to 90%, and the peak time (pulse-on time or duty) from 10 to 90%.
i) Pulse in AC TIG (Square Wave Only)
In AC TIG, the pulse function is only available in the square wave form (the standard wave form). Also, the AC pulse
frequency adjustment range is much narrower than the DC pulse frequency range and is typically used only for low-
speed pulse applications. Due to the wide range of AC frequencies, and to avoid interferences, the pulse frequency
cannot be set higher than the AC frequency. AC low-speed pulse applications enable you to obtain the stack of dimes
look and also enable you to fix less attractive welds simply by running the torch over them at a steady, slow speed that
allows the low-speed pulse to put the ripples in. You can also join material with low-speed pulse using a lay wire
technique. In place of high-speed pulse, we recommend the use of the triangular wave form instead, which achieves
similar results. With the Invertig 301/400, you can adjust the pulse frequency from 0.4 to 20.0 PPS, the background amps
from 10 to 90%, and the peak time (pulse-on time or duty) from 10 to 90%.

16
j) Pulse in Stick (Square Wave Only)
Advantages of Pulse Welding
Pulse welding includes ALL of the following advantages, but not all at the same time. At a later point in the manual, we
cover, in more detail, suggested settings regarding how, when, and where certain situations apply.
 Visually spatter free (MIG & TIG only, though still reduced spatter when stick welding)
 Higher travel speeds
 Deeper penetration
 Less heat input, which equals less material distortion
 Ability to weld thinner material than you could without pulse
 Superior control of the weld puddle, especially when welding out of position
 Easily join materials of differing thicknesses
 Better gap bridging when welding materials with poor fit up
 Ability to make leak-tight welds
 Improved bead appearance
 Ability to use one size bigger welding rod than normal
 Weld on thinner material without burning through
 Easier for beginner welders
Disadvantages of Pulse Welding
 Pulse welding can interfere with sensitive electronics like pacemakers and auto-darkening welding helmets
 Low pulse frequencies (less than 1.5Hz) can be perceived as unpleasant, sound-wise, by the operator (TIG and Stick
only)
Common Stick Welding Electrode Types and Descriptions
6010—Rod with a cellulosic coating, fast freeze puddle, deep penetration, slag can be hard to remove, less elongation of
welds, not the most attractive welds, may present some hydrogen cracking. However, rod runs in all positions, including
vertical up and down. Also forgiving for some contamination of the parent metal. An excellent choice for root passes.
6013—Rod with a titania potassium coating that runs on old and simple AC (alternating current) stick welders. Typically
referred to as the farmer’s rod.
7014—Rod with properties similar to 7018, but also designed to run on older, simpler stick welders.
7018—Rod with a low hydrogen coating that flows nicely. Probably the most popular rod in today’s market. Builds a
thick, easy to remove slag layer on top of the weld, medium penetration, excellent bead appearance, puddle stays wet
and fluid much longer than 6010, higher tensile strength than 6010. A good choice for the maintenance welder and even
to do x-ray quality structural welds.
The rods listed above represent the most common types of rods available today. However, an almost endless selection of
various rods exist. We simply cannot cover all rod types in the manual. Since 7018 is probably the most popular welding
rod available today, please find a few pointers below. How do you find the right amperage when you lose the box? The
general rule of thumb with 7018: For every 0.001” of welding rod diameter, you need about 1 amp. What does this
mean? Will these numbers be a perfect fit for every rod manufacturer and every position you weld 7018 rod in?
No, but the numbers get you really close.
Fig. 8
Rod Diameter Fraction
Rod Diameter Decimal
Required Amperage
3/32”
0.09375” rounded to 0.094
94 amps
1/8”
0.125”
125 amps
5/32”
0.15625” rounded to 0.156”
156 amps
3/16”
0.1875” rounded to 0.188”
188 amps

17
Now Let’s Talk Pulse
How does pulse work? How do I set up the Invertig 301/400 to pulse weld in Stick mode?
For manufacturing or critical code repairs, welding procedures are typically specified. These welding procedures spell
out everything including, but not limited to, pre-heat of the part, alloy of the filler rod, amperage setting, travel speed,
bead size, multi-pass weld number of passes (if applicable), inter-pass temperature, post-heat, and so on. No variable
stays undefined, and there is no room for creative freedom.
In the repair field, however, things look a little bit different. In Europe, procedures that spec pulse welding exist. But the
pulse welding process is relatively new in the U.S., so no written procedures that spec pulse welding currently exist. For
example, a 1/8” 7018 rod typically has an operating range between 90-160 amps. But many people like to run them
between 120 and 130 amps.
To pulse weld, the operator first sets the welding current and then chooses a pulse frequency. The machine
automatically sets the background current and a pulse-on time of 50%. So what does that mean when you weld? Let’s
say, for example, you dialed the machine in to 130 amps. 50% of the time the arc is lit, the welding current is 130 amps.
The other 50% of the time the arc is lit, the welding current is 65 amps. You may notice that 65 amps is outside of the
manufacturer’s recommended amperage range. While the background current is on, the amperage is high enough to
maintain an arc but low enough to where there is no metal transfer happening.
The benefit of this is especially apparent at very low frequencies (1 to 1.5Hz). The out-of-range background current
allows the puddle to cool down and also allows the weld to partially solidify around the edges. This makes out-of-
position gap bridging on poor fit up much easier than it is with a classic stick welder. You will not sacrifice any
penetration because, during the 50% on time at 130 amps, the rod burns as hot and deep as it normally would on a
classic stick welder at 130 amps.
This may prompt you to ask: If the amperage range of the rod is 80 or 90 to 160, why not set the welding current at 160
amps so the Invertig sets the background current to 80 amps? The amperage ratings, essentially, would be well
within the specs then. This is absolutely possible and a good setting. However, this setting is very hot and metal transfer
occurs the entire time. This, paired with a 3 to 4Hz pulse frequency, makes for a very high travel speed in the horizontal
or flat position. Plus, the heat input into the work piece is enormous.
Knowing what we know now, let’s go back to the beginning and look more closely at the advantages of pulse welding.
Pulse welding includes ALL of the following advantages, but not all at the same time.
 Visually spatter free (MIG & TIG only, though still reduced spatter when stick welding)
 Higher travel speeds—As just covered, with the right settings, the travel speed can be greatly increased.
 Deeper penetration—If you choose the same or similar settings to the ones for a higher travel speed, the overall heat
input and penetration increases also.
 Less heat input, which equals less material distortion—More like the first example about setting the welding current
to 130 amps.
 Ability to weld thinner material than you could without pulse—To achieve this, you would reduce the max amperage
even more. For example, 110 amps or 120 amps with a 55 amp background current, which makes for an average heat
input of roughly (110 + 55)/2 = 82.5 amps. (The actual heat input may be somewhat higher, especially with higher
pulse frequency settings). With this setting, you can weld materials with a 1/8” rod when you would normally need to
weld with a 3/32” rod.
 Superior control of the weld puddle, especially when welding out of position—You have better control on lower pulse
frequencies because the puddle has time to partially solidify.
 Easily join materials of differing thicknesses—More like the first example about setting the welding current to 130
amps.
 Better gap bridging when welding materials with poor fit up—More like the first example about setting the welding
current to 130 amps.
 Ability to make leak-tight welds—Spray arc or stick welding arc, in general, works better at making leak tight welds
than short arc MIG, for example.
 Improved bead appearance—Pulse welds, especially lower frequency pulse welds (2Hz or less) make really nice and
defined ripples on the top of the weld bead; welds like this are generally thought to be aesthetically appealing.

18
 Ability to use one size bigger welding rod than normal—To achieve this, you would reduce the max amperage even
more. For example, 110 amps or 120 amps with a 55 amp background current, which makes for an average heat input
of roughly (110 + 55)/2 = 82.5 amps. (The actual heat input may be somewhat higher, especially with higher pulse
frequency settings). With this setting, you can weld materials with a 1/8” rod when you would normally need to weld
with a 3/32” rod.
 Weld on thinner material without burning through—More like the first example about setting the welding current to
130 amps.
 Easier for beginner welders—The pulsed stick process is extremely forgiving.
With the Invertig 301/400, you can adjust the Stick pulse frequency from 0.4 to 5 PPS, the background amps from 10 to
90%, and the peak time (pulse-on time or duty) from 10 to 90%.
k) Hot-Start for Stick
Hot-start when stick welding gives a short burst of current to light hard to strike electrodes.
l) Hot-Start for TIG
The hot-start for TIG function is available in AC and in DC. Hot-start provides a short (in the range of milliseconds) burst
of current to ignite the arc. Many other welding manufacturers offer hot-start, but they typically don’t give the operator
the option to adjust hot-start. Hot-start ensures arc starts with tungsten electrodes that are not fresh and pristinely
ground, as well as material that is not perfectly prepared. If your material and torch are in mint condition, and you weld
on very thin material, you can turn hot-start off. This is very uncommon in the industry because most machines have arc
starting difficulties at low or very low amperages. Some machines even include a hidden, non-adjustable hot-start
feature. The ability to turn hot-start off allows you to have a true 4 amp arc start, which can be extremely important
when welding thin and critical material.
m) Hot-Start vs. Starting Amps in TIG
Starting amperage refers to the minimum that the foot pedal can go to without extinguishing the arc. When using a torch
switch in 4T or RESET mode, the starting amperage can also play a role as a limiting factor in regard to the Initial Amps
and Final Amps percentages. You can adjust the Initial Amps value and the Final Amps value from 10 to 90%. If, for
example, you set the welding current to 100 amps, and you set the Initial Amps and Final Amps to 10%, the Initial Amps
and Final Amps would be 10 amps; if you set the welding current to 150 amps, and you set the Initial Amps and Final
Amps to 10%, the Initial Amps and Final Amps would be 15 amps.
n) HF-, LIFT-, & Scratch-Start
When welding near sensitive electronics, for example in hospitals or assisted living homes or around computers or
computer control modules in vehicles, we STRONGLY recommend turning off HF (high frequency arc start). Even an AC
arc on a modern inverter can be ignited in lift-arc mode! HF travels long distances; 10 to 20’ traveling distances are very
common. In some instances, HF interferes with electronics in neighboring buildings if they are on the same transformer!
Unlike regular welding currents that travel the path of least resistance, HF is unpredictable.
Lift start, not to be mistaken for scratch-start, can be used to ignite a DC or an AC welding arc with the Invertig 301/400.
If you use a foot pedal, turn HF off in the menu, and then touch the clean and cold tungsten electrode to the clean
material you plan to weld on. Depress the foot pedal a little bit, at minimum, which activates the contact switch (the
more you depress the foot pedal, the easier the arc will ignite). At this point, NO welding current flows through the
tungsten, you are not shortening anything out, and only a very small control current flows through the torch, just sensing
the short circuit. The moment you lift the torch and break the short circuit, the machine applies the welding current and
ignites the arc. Typically, the tungsten electrode does not get contaminated this way, the arc starts smooth (not violent),
and everything is very controllable using the foot pedal. To choose between HF start and Lift start is more a matter of
personal preference and what a person is used to. When welding longer beads, the difference might appear negligible to
some people, but when making a bunch of spot or tack welds, HF is definitely more comfortable.
Scratch-start is typically done on older engine drives or stick welders. The difference is the arc is lit at full power by
either striking the electrically hot tungsten electrode on the base metal or flicking the filler rod between the tungsten
and the parent metal. In either case, unless you have trained for this procedure well, contamination of the tungsten is
likely, and welding can be uncomfortable. The Invertig 301/400 can do scratch-start only when using a foot pedal

19
without HF and by depressing the foot pedal before the tungsten touches the base metal. At this point, whatever you set
the machine to (however much the foot pedal is depressed) the arc will strike at that amperage. This is, by far, the least
preferable arc starting method with the Invertig.
o) Pipe Mode
We specifically designed the Pipe mode for pipe welding and pipe training in an educational facility. When you activate
Pipe mode, you can only choose between Stick and TIG 2T (both DC only modes). If you plug in a foot pedal or other
remote control, the remote control symbol blinks since all remote control functions are deactivated. In TIG 2T, the
welding output is now hot and the gas solenoid valve in the machine is deactivated. At this point, you typically install a
26 Series air-cooled torch with a gas valve on the torch head, and then hook the torch up directly to an Argon tank via a
flowmeter or regulator. Torches like the Heavy Hitter 350, with full size gas lenses, are popular torches for that. In order
to adapt the Dinse outlet of the Invertig to an LC-40 or Tweco #2 adapter, part number DA-5095 is required.
The Invertig can only be used in lift-arc mode only for pipe welding. To terminate the weld, you cold snap out or set a
slope down timer to initiate the weld termination procedure. The PIPE mode reflects a very common setup and method
that is taught at countless colleges and welding schools across the United States and used daily in the field to weld pipe in
the oil and the food processing industries.
Procedure for TIG Welding with LIFT Start in PIPE Mode
Start Welding:
) Bring the TIG electrode (tungsten) into contact with the work piece.
) Lift the torch from the side, move slightly away from the work piece, and start the welding process.
End Welding:
) With the slope down function turned on, you can end your weld by regulating the distance between the arc and the
work piece as shown in Fig. 9.
) With the slope down function turned off, you must pull the arc away from the work piece to end the welding process.
Fig. 9 Shows how you can lift the torch
from the work piece to start the slope down
process and end welding.
Fig. 10 The slope down function is turned
off at 0.1 seconds as shown. If you increase
the slope down value, then Fig. 10 is
applicable to terminate the arc.
PRO TIP: When you turn on Pipe Mode, the machine automatically turns off HF-start (as this is a key feature of
the Pipe Mode program). When you turn off Pipe Mode, HF does not turn back on automatically—you have to
turn HF back on yourself. You can do so by pressing button E (Fig. 11) followed by button D (Fig. 11).
p) Amperage Limitation in Single-Phase (Invertig 400 AC/DC Only)
In single-phase, you can limit the output of the Invertig 400 to 300 amps. This can be an advantage when a torch is used
that is not rated for 350 amps, but only for 300 amps, like the CK230. This way, accidental torch failure can be prevented.
Also, when welding on single-phase the duty-cycle is limited compared to 3-phase operation. The duty-cycle at 300 amps
is higher than at 350 amps so if the machine is frequently used on thicker material it helps with higher duty-cycles as
well.

20
q) Smart Water-Cooler Operation and Control
The smart water-cooler is controlled by the welder, but the smart water-cooler also controls the welder. The pump and
the fan in the cooler are on-demand, meaning they only run if and when necessary. The fan is also variable speed. If the
fluid level in the cooler is low, the cooler communicates with the welding machine, turns the welding output off, and
displays an error message. No matter what phase and what voltage you run the machine at, the machine and the cooler
will automatically adapt without switches or jumpers.
9) FRONT PANEL CONTROLS
Fig. 11
A (Select Mode Button)—Allows you to access different welding modes (STICK, 2T, 4T, SPOT, & RESET) by repeatedly
pressing.
B, C, D, E (Setup and Selection Buttons)—The functions of these buttons differ depending on which mode the machine
is in and what setup screen the machine is on. The function of the individual button is shown in the LCD above each
button.
F (Encoder)—Turning the encoder adjusts the amperage. (This can also be done while welding). The encoder also
makes all adjustments (pulse settings, AC settings, etc.).