Taurus TIG-300PI AC/DC User manual

Digital Inverter AC/DC Pulse TIG
Welding Machine
TIG-300PI AC/DC
Operation Manual
Read this manual carefully before installing,
operating and maintaining the machine.

- 1 -
Description: This machine is designed and built to weld ferrous and non-ferrous
metals.
Disclaimer: The information, illustrations and instructions described in this manual
are based on the latest product information available at the time of publication.
The manufacturer and distributors reserve the right to modify the contents of this
manual at any time. Modifications may result following product modifications and the
manufacturer and distributors are not obliged to notify any organization or individual
of such modifications. Welding work must be executed only by professionally trained
and qualified individuals. Therefore, the manufacturer and distributors will only
accept responsibility for product quality. No liability, joint or several, shall be
accepted for incidents including but not limited to loss of profit resulting from
omissions or misdirection that may be printed in this operation manual. This manual
will contain as far as possible preventive and safe operation measures related to the
equipment but cannot exclude the occurrence of accidents. Therefore, the
manufacturer and distributors shall not be liable for any direct or indirect, joint or
several liability for any incidental or consequential damages which may occur. For
detailed health and safety information, the relevant professional agencies and
manufacturers of consumables such as welding materials and flux should be
contacted.
Warranty Exclusions:
✓Consumable items such as welding wires, welding flux, fuses, quick connectors,
drive rollers, tension rollers, etc.
✓Machine damages caused by incorrect voltage input or power surges.
✓Machine or parts malfunction owing to incorrect connections or user operation.
✓Illegal disassembly or re-fitment of the machine without permission of the
manufacturer, resulting in damage or malfunction.
✓Accidental damage during shipment, transportation and storage.
✓Damage owing to incorrect handling, natural disaster and other force majeure
occurrences.

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CONTENTS
Safety Precautions ----------------------------------------------------------3
Warnings -----------------------------------------------------------------------4
Packaging and Transportation-------------------------------------------------- 7
Parameters --------------------------------------------------------------------------8
Product Description --------------------------------------------------------------- 8
Working Principle ------------------------------------------------------------------13
Installation and Wiring ------------------------------------------------------------14
Brief Procedure for Welding Operation--------------------------------------- 17
Maintenance ------------------------------------------------------------------------22
Common Machine Malfunctions and Solutions ----------------------------23

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Safety Precautions
The equipment is designed for use by qualified personnel who have completed
professional training and have obtained a qualification certificate as a welder. The
operator shall have sufficient professional knowledge of welding, cutting and circuitry. The
machine should be operated only after having read and fully understood all the safety
precautions and warnings contained in this manual and those generally applicable to
welding operations. The risk of personal injury and damage to equipment is reduced by
safety precautions being followed when using tools and equipment. This machine is
easy to operate and the selection of its functions is straight forward. Improper use and
maintenance will reduce the safe operation of the machine and the following safety
precautions must be followed:
1. The operator must be suitably qualified and certificated before operating the
equipment.
2. A qualified professional should be employed to ensure that the machine and all
cables are properly connected, grounded and installed.
3. Personal protective equipment approved by the local safety authority must be
used. All relevant safety procedures must be adhered to.
4. Before operation, insulation layers on wires and cables as well as connection
sequences should be inspected and corrected if required.
5. Repairs and maintenance should be carried out by qualified technicians only
after the machine has been disconnected from the electricity supply.
6. Operating the machine in a humid environment may result in a short circuit or
may cause an electric shock to the operator.
7. Modifications to the machine or equipment are not allowed.
8. The disposal of scrap machine parts and equipment must comply with local
regulations.

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Warnings
Welding and cutting operations are specialised operations which present a certain
degree of risk. Professional training, correct operating procedures and protective
measures reduce the accident risk and damage to equipment.
Personal Safety Protection
Welding and cutting operations generate noise, bright light and
high-temperature sparks which will cause harm to human
hearing, eyes and skin unless personal protective measures are
implemented and proper operational instructions are adhered to.
1
Wear flame retardant personal protective equipment (PPE) such as gloves,
overalls, welding helmets with correct shading filter, shoes and aprons to
protect against thermal radiation, sparks and hot metal particles.
2
Hot sparks and metal fragments can cause skin damage. Avoid clothes with
front pockets and button-up sleeves and collars.
3
Use appropriate flame-retardant shields or curtains to protect bystanders from
arc radiation and high temperature sparks. Bystanders also need to wear a
protective helmet fitted with a shading filter to protect face and eyes or a pair of
spectacles fitted with shading filters.
4
Avoid burns and scalds by not touching a welded work piece with bare hands.
Fire and Explosion Dangers
Welding and cutting operations generate high-temperature flames
and arc which can cause fires and explosions. The same applies to
welding slag and sparks.
1
Operators and bystanders must be protected from arc, sparks and metal
fragments.
2
The welding/cutting area should be free from flammable and explosive
materials. Should these materials be required in the welding/cutting process,
flame retardant covers should be applied.
3
Care should be taken to avoid fire hazards from cracked floors and walls.

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4
Welding and cutting on sealed gas tanks will cause explosions. These
operations are prohibited.
5
Welding and cutting areas must be provided with adequate fire extinguishing
equipment. Regular testing for efficiency of this equipment is compulsory as is
training of staff in the use of the equipment.
6
Once the welding/cutting operation is completed, check for any high
temperature spark or metal which might cause a fire and immediately dispose
of it. If necessary, employ the assistance of a firefighter.
Electricity Hazards
Electric shock can cause serious injury or even death to the
individual when contact is made with live wires. Humid conditions
can add to the risk and great care should be taken when welding or
cutting machines are used in these conditions.
1
Reliable grounding of machine and work piece as well as a secure ground
clamp, is important.
2
Insulation layers of electric wires and cables must be checked regularly for
wear and replaced if necessary.
3
All equipment used and clothing worn during the welding/cutting operation
should be free from moist and kept dry.
4
Do not make direct body contact with any live electrical parts.
5
Wearing rubber-insulated shoes and standing on an insulated platform greatly
reduce the risk of accidental shock.
6
Refrain from replacing the ground cable on the machine with wires not
suitable for the task.
7
The machine operates on high voltage and capacitors remain charged even
after power is switched off. Removing covers for maintenance procedures
must only be executed by qualified professionals.
Protective Measures for Electromagnetic Fields
Electric current flowing through a conductor produces magnetic
fields (EMF). The discussion on the topic of the effects of EMF on
the human body is ongoing worldwide and up to the present no
evidence has been forthcoming proving negative effects on health.

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However, it would be wise to limit exposure to EMF as far as
possible and the following procedures are suggested:
1
Welders and cutters with cardiac pacemaker implants should obtain medical
advice on the effects of EMF on the implant.
2
Welders should minimise the possibility of electromagnetic field damage
through the following methods.
2.1
Route the electrode and ground cables together and, where possible, secure
them with tape.
2.2
Do not wrap wires and cables around arms or coil power cables around body
parts. If possible, keep cables away from the body.
2.3
Keep the distance between the ground clamp to the workpiece and the
electrode as short as possible.
2.4
Keep a safe distance between the operator and the welding/cutting machine.
Protection from Fumes and Gases
During the welding or cutting process, fumes can be produced
which may be detrimental to health.
1
The working area should be well ventilated and welding/cutting activities
should not be executed in confined spaces. Eye, nose or throat discomfort
can be the result of inadequate ventilation.
2
Welding and cutting in or near locations where chlorinated hydrocarbon
vapours are produced such as degreasing, cleaning and spraying operations,
should not be undertaken since phosgene, a highly toxic gas as well as other
irritants can be reaction products.
3
The industry offers a variety of respiratory masks and must be used in
conditions where clean breathing air is required.
Gas Cylinder Safety
Gas leaks can occur on cylinders connected to welding/cutting
operations if the system is not properly managed and maintained.
A ruptured cylinder or relief valve can cause serious injury or can
even be fatal.

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1
Gas cylinders should be kept away from extreme temperatures and fire
sources. Scratching on cylinder walls with hard objects should be avoided.
2
A flowmeter should be installed on the gas cylinder in use in accordance with
the manufacturer's operating instructions. Quick-coupling connectors must
not be used and gas hose fittings should be tested for leaks.
3
Gas cylinders must always be kept upright and chained or belted to a cylinder
trolley, base, wall, post or shelf. Never fix a gas cylinder to a worktable or
machine: It can become party to an electrical circuit and explode.
4
Ensure that the cylinder valve is closed when not in use. If there is no hose
connected to the flowmeter then cover the outlet with a dust cap.
Protection Against Moving and Rotating Parts
Moving parts, such as fans, rotors and belts, can be
hazardous.
1
Ensure that all protective covers, doors and panels on the machine are closed
or securely intact before starting an operation.
2
Ensure that maintenance on machines are only carried out by qualified
technicians.
3
Ensure that hands, hair, clothing and tools are safely out of range from
moving and rotating parts.
Packaging and Transportation
1. Pay attention to and comply with packaging, storage and transportation
instructions which are clearly identified on the containers.
2. Always handle all containers with care.
3. Equipment must be stored in waterproof, moisture proof and well-ventilated
facilities within the temperature range -25°C - 55°C.

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Parameters
Product Description
This welding machine in the AC/DC TIG series, inverts the 50/60Hz power supply to
a high-frequency, high-voltage power supply of up to 20KHz. The inversion process
is facilitated by a powerful IGBT device followed by step-down rectification and
pulse-width modulation (PWM) technology producing a high-power DC output
Model
TIG-300PI AC/DC
Item
Value
Rated input voltage
3PH---AC380V±15% 50/60Hz
Rated input power :
12.0KVA
Rated input current :
16.5A
Rated duty cycle :
60%
Output current range :
10A~300A(TIG) / 20A~250A(MMA)
Open circuit voltage :
70V
Pulse frequency ：
0.5Hz-100Hz
Duty cycle：
20%-80%
AC frequency：
50Hz-150Hz
AC cleaning width：
20%-50%
Current up slope time (S)：
0.1-5
Current down slope time (S)：
0.1-5
Gas pre-flow time (S)：
0-10
Gas post-flow time (S)：
5-25
Package dimensions(mm) :
630*315*530
N.W.:(kg):
22

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suitable for welding. The advanced inverter technology allows for the construction of
a smaller volume and light-weight, stable and reliable transformer with a 30%
improved efficiency.
Added to the advantages of the inverted power supply, the machine has good
dynamic characteristics and performance, offers a stable arc and good quality
welding as well as ease of control.
Welding machines in this inverter series are suitable for also welding non-ferrous
metals, including stainless steel, alloy steel, carbon steel, copper, and aluminium.
These machines are widely used in, amongst others, electric power construction,
building construction, furniture manufacturing, hardware and kitchen equipment
production. In AC current mode, Al-alloy materials can be welded such as bicycle
frames and indoor/outdoor decorative items.
The inverter welding machines in this series are manufactured in accordance with
IEC60974-1 <Arc Welding Equipment - Part 1: Welding Power Sources >. Safety
Requirements for Arc Welding Equipment.
1. Product Functions and Features:
1.1. Multi-function, digital-controlled welding machines featuring DC TIG, pulsed
DC TIG, pulsed AC TIG and MMA welding in one simple designed, light and
small size unit.
1.2. Multi-layer control circuit boards ensure high reliability and a long service life.
1.3. The secondary inverter technology produces a pure square wave output,
excellent arc-force performance and a wide cleaning range, a combination
ensuring high quality welding results.
1.4. Easy arc start facilitated by the high-frequency, high-voltage arc ignition circuit
and stable, reliable arc performance.
1.5. Pulsed welding with adjustable pulse frequency ensuring high-quality welding
on thin metal sheet, dissimilar metals, varying thickness materials and even for
double-sided forming welds.
1.6. Foot control available to adjust current freely, improve welding efficiency,
reduce welding difficulties and ensure welding quality. Increase current for rapid
heating and decrease current to generate a weld seam.
1.7. Overheat protection improves machine reliability.

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2. Appearance Diagram
TIG-300PI AC/DC
Panel：
1
Control panel
2
Control cable connection socket: Connects the control cable of the TIG
welding torch or the pedal switch.
1
1
2
1
5
1
3
1
4
1
6
1
17
``
19
6`
`
20
``
14
16
``
18
5`
`
13
15

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3
Gas electric outlet: Connect gas electric plug of the TIG welding torch.
4
Terminal socket - negative pole (-): Connect TIG welding torch. In MMA
mode, connect electrode holder cable set in direct current electrode negative
way, connect earth clamp cable set in direct current electrode positive way.
5
Remote control line socket: Connects to the remote control box or to the
remote pedal switch.
6
Terminal socket - positive pole (+): In DC TIG mode, connect earth clamp
cable set. In MMA mode, connect earth clamp cable set in direct current
electrode negative way, connect electrode holder cable set in direct current
electrode positive way.
13
Digital diode display: Displays function values and real-time current output.
14
Welding parameter adjustments and selections : Rotate to adjust the
parameter values.
15
Parameter selection push button: In TIG mode selections can be made
from the following: pre-flow, start amps, upslope, peak amps, duty cycle,
pulse frequency, base amps, downslope and post-flow. When the
corresponding light is lit, the selected item can be adjusted to the required
value.
16
Parameter light: The corresponding parameter is adjustable when the light
is lit.
17
Welding process push button: Select between TIG and MMA and the
machine is operable when the corresponding indicator light is lit.
18
2T/4T: Press the button to select between 2T (continuous arc) and 4T (arc
stopping) and the corresponding light indicates the selected mode.
19
Pulse: Pressing this button allows selection between pulse and non-pulse
welding. The selected mode is active when the corresponding light is lit.
20
AC frequency / AC clean width: While in AC TIG welding mode, press the
button to select between AC frequency and AC clean width. The
corresponding light indicates the selected mode.

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3. TIG Mode Parameter Adjustments
3.1. Pre-Flow
Indicates the gas flow prior to arc start. Pre flow duration is adjustable from 0s to
10s.
3.2. Start Amps:
Indicates the startup amperage adjustable from 10A to approximately 300A when
the trigger is pressed. It serves to preheat the material.
3.3. Up Slope
Indicates the time from the arc-start up to the preset power level. It is adjustable
between 0.1 and 5s.
3.4. Peak Amps
In the pulsed welding mode, the peak current is high and can melt the welding wire
and the weld pool to form a welding seam. Also called pulse current, it can be
adjusted between 10A and approximately 300A.
3.5. Base Amps
The lower amperage for each pulse is set. It not only serves arc maintenance but
also arc stability and assists preheating of the following weld pool. Base Amps are
adjustable between 10A and 300A.
3.6. Duty Cycle
It expresses the percentage each pulse cycle spends at peak amperage per second.
The wider the pulse, the larger the weld pool of the welding seam and vice versa.
Duty cycle is adjustable between 20% and 80%.
3.7. Pulse Frequency
Refers to the number of pulse cycle changes per second per unit time and is
adjustable between 0.5Hz and 100Hz.

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3.8. AC Frequency
Not adjustable in DC TIG mode. A low frequency is suited for high-current
wide-seam welding, while high frequency is suited for thin sheet and narrow seam
welding since it increases the melting speed and force. It is adjustable between
50Hz and 150Hz
3.9. AC Clean Width
In the AC TIG welding process, it indicates the percentage adjustment of negative
and positive AC half-wave widths which cleans the oxidised surface of a workpiece.
It is adjustable between 20% and 50%.
3.10. Downslope
Indicates the time the welding current is stepped down to end the arc. It is adjustable
between 0.1 and 5s.
3.11. End amps
Indicate the reduced welding current at the end of the process and is aimed at
obviating the formation of a crater at the completion of the weld. It is adjustable
between 10A and 300A.
3.12. Post flow
Indicates the time gas continues to flow after completion of the weld. The
continued gas flow will prevent oxidation of the molted metal, ensuring quality of the
weld seam and also act as a coolant. It is adjustable between 5 and 25s.
Working Principle
1. Diagram Explaining Working Principle

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1.1. A bridge rectifier converts AC to DC;
1.2. After secondary rectification and reactor filtering, output welding current is
delivered that meets the welding requirements;
1.3. Controlled by PWM the IGBT inverts the DC to 20KHz AC which is transmitted
via a high-frequency transformer;
1.4. The in-time protection circuit provides signals to the PWM warning for overheat
and over-current situations;
1.5. A closed-loop control system ensures a good anti-grid fluctuation ability and an
excellent cutting performance.
Installation and Wiring
1. Location Requirements
1.1. The machine should not be installed in an area where it is exposed to direct
sunlight or rain but where the humidity is as low as possible and the ambient
temperature is within the range of -10°C - 40°C.
1.2. The machine should be installed on a flat, preferable level surface but, in any
case not on a surface with an inclination of more than 10°.
1.3. The machine should not be operated in a work station exposed to wind.
Should a windy environment be unavoidable, suitable screening should be
installed.
1.4. In order to allow for efficient ventilation, a clear space of at least 20cm should
be allowed in front of and behind the machine as well as at least 10cm at each
side.
2. Power Input Requirements
The power supply waveform should be the standard sin wave, the rated voltage
380V±10% 50/60Hz. Three phase voltage unbalance should be ≤5%.
wave.

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3. Main Power Supply Connection
Pay attention to prevent electric shock
Wear goggles
Take note of the following when the machine is connected to the main power
supply:
3.1. The connection must be carried out by a qualified electrician or technician.
3.2. The connection must be in compliance with national and local regulations.
3.3. Before the connection is carried out, the main power supply to the control box
must be switched off.
3.4. An earth cable set must be securely connected from the machine to the
work-piece. The machine must be earthed.
3.5. Ensure that the required power supply of the machine (as printed on its
nameplate) corresponds to the main power supply.
3.6. The connection screws on the terminal block must be tight ensuring a solid
connection between the machine cable wires and the main power supply.
3.7. The correct wiring procedure is explained in the following diagram:
Model
TIG-300PI AC/DC
Power supply：
AC380V±15% 50/60Hz 3PH
Rated input current：
16.5
Input cable：
≥2.5mm2
Output cable：
35mm2
Ground cable：
≥4mm2

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Wiring of three phase AC, 50/60Hz welding machine
No.
Item
No.
Item
1
Power cord
3
Terminal block
2a
Live wire L1
4
Overcurrent protection device
2b
Live wire L2
5
GND
2c
Live wire L3
6
Earth wire terminal block
2d
Earth wire
7
Electric control box
4. Gas-cylinder Connection
Explosion hazard
Prevent gas
inhalation
Wear goggles
Warning: The following safety instructions are important when connecting a
gas cylinder to the welding machine.
4.1. The cylinder must be fixed to a wall, cylinder rack or support. Its centre of
gravity can cause the cylinder to topple resulting in injury and material damage.
4.2. The cylinder must be placed out of reach of the operator's welding station and
not in contact with the work table or the welding machine.
4.3. Connect the gas hose firmly from the flowmeter outlet to the gas inlet situated at
2b
3
7
6
4
4
5
1
2c
2d
2a

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the back of the welding machine. Gas leakage is not allowed.
4.4. Adjust the flowrate in accordance with the manufacturer's recommendation.
Generally, 5 -10 litres/min.
Brief Procedure for the welding operation
1. Before Welding
1.1. Wear the necessary welding protection equipment such as helmet, mask,
earplugs, protective clothing, gloves, insulating safety shoes.
1.2. Confirm the electrical grid connected to the welding machine is consistent
with the correct power supply of the machine.
1.3. Confirm that the insulation layers on all the wires and cables of the welding
machine are intact and that the cable set is secure and correctly connected to
the machine.
1.4. Confirm the machine is freely vented and that the vents on the machine are
not obstructed and no objects are lying on the machine body.
2. TIG Welding Procedure
2.1. Securely connect the earth cable and the TIG welding torch.
2.2. Ensure the Argon gas assembly consisting of cylinder, regulator, flow meter and
hose are connected and clamped tightly to the copper inlet connector on the
rear panel of the machine.
2.3. Switch the power on and ensure the power light is lit and the fan is operational.
2.4. Select TIG mode on the front panel and set the required parameters. Direct the
torch towards the workpiece and start the welding process. If required, adjust
the parameters during the welding process. A guideline table for TIG welding
parameters is detailed below.
2.5. Turn off the machine and the electric control box once welding task is
completed
2.6. Schematic diagram in TIG mode:

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Direct Current Electrode Negative (DCEN): Suitable for acid electrode
welding.
Direct Current Electrode Positive (DCEP): Suitable for alkaline and cellulose
electrode welding.
No.
Item
No.
Item
1
Welding machine
3
Earth clamp
2
Electrode holder
4
Work piece
.
3. MMA Welding Procedure
3.1. Securely connect the earth cable and the electrode holder cable.
3.2. Switch the power on and ensure the power light is lit and the fan is operational.
3.3. Select MMA mode on the front panel and preset the welding current in
accordance with electrode specifications. (Consult the reference table below).
3.4. Start the welding process according to normal procedure.
3.5. Turn off the machine and the electric control box once welding task is
completed.
3.6. Schematic diagram in MMA mode:
2
3
3
1
4
3

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Direct Current Electrode Negative (DCEN): Suitable for acid electrode
welding.
Direct Current Electrode Positive (DCEP): Suitable for alkaline and cellulose
electrode welding.
No.
Item
No.
Item
1
Welding machine
3
Earth clamp
2
Electrode holder
4
Work piece
4. Guideline Table for TIG Welding Parameters
Parameters are bases on the workpiece material. When a workpiece with thickness
≥4.0mm is welded, multi-layer and multi-pass welding is recommended.
Thickness
（mm）
Amperage
（A）
Diameter of
tungsten
electrode（mm）
Diameter
of wire
（mm）
Gas flow（L/min）
Stainless
steel
Titanium
0.3~0.5
10∽40
1.0
1.0
4
6
0.5∽1.0
20∽40
1.0
1.0
4
6
1.0∽2.0
40∽70
1.6
1.6
4∽6
6∽8
2.0∽3.0
80∽130
2.0∽2.4
2.0
8∽10
8∽10
3.0∽4.0
90∽150
2.4∽3.2
2.5
10∽12
10∽12
4.0
110～150
2.4～3.2
3.0
10∽14
12∽14
2
3
3
1
4
3