LOKERMANN GRAND TIG 200 DC User manual

USER MANUAL
INVERTER Based Welding Machines
GRAND
TIG 200 DC
IMPORTANT: Read this OPERATOR MANUAL together
with PRESCRIPTION AND COMPLIANCE MANUAL before
to use this equipment. In case of loss one of two parts
contact immediately your dealer.
Allow the operator to consult this manual.

GRAND
TIG 200 DC
1INSTALLATION WARNING
2 OVERVIEW
2.1 Features
2.2 Technical Data
2.3 Brief Introduction
2.4 Duty cycle and Over-heat
2.5 Working Principle
2.6 Volt-Ampere Characteristic
3INSTALLATION & OPERATION
3.1 Layout for the front and rear panel
3.2 Power supply input Connection
3.3 Installation & Operation for MMA Welding
3.3.1 Set up installation for MMA Welding
3.3.2 Operation for MMA Welding
3.3.3 MMA Welding
3.3.4 MMA Welding trouble shooting
3.4 Installation & Operation for TIG Welding
3.4.1 Set up installation for TIG Welding
3.4.2 Operation for TIG Welding
3.4.3 TIG GUN Control
3.4.4 Tig Welding Techniques
3.4.5 Electrodes
3.4.6 TIG Welding trouble shooting
3.5 Operation environment
3.6 Operation Notices
4MAINTENANCE & TROUBLESHOOTING
4.1 Maintenance
4.2 Troubleshooting
4.3 List of error code
4.4 Electrical schematic drawing
CONTENT

INSTALLATION WARNING
This machine is certified according to 60974-10:2014 Arc Welding Equipment Part 10: Electromagnetic
compatibility (EMC) requirement and the EUT belongs to Group 2 Class A.
WARNING: This Class A equipment is intended for industrial use and it is not intended for use in
residential locations where the elctrical power is provided by the public low-voltage supply system.
There may be potential difficulties in ensuring electromagnetic compatibility in those locations, due to
conducted as well as radiated disturbances.
WARNING: This equipment does not comply with IEC 61000-3-12. If it is connected to a public low-
voltage system, it is the responsability of the installer or user of the equipment to ensure, by consultation
with the distribution network operator if necessary, that the equipment may be connected.
Assessment of area
Before installing arc welding equipment the user shall make an assessment of potential
electromagnetic problems in the surrounding area. The following shall be taken into account:
a) other supply cables, control cables, signalling and telephone cables, above, below and
adjacent to the arc welding equipment;
b) radio and television transmitters and receivers;
c) computer and other control equipment;
d) safety critical equipment, for example guarding of industrial equipment;
e) the health of the people around, for example the use of pacemakers and hearing aids;
f) equipment used for calibration or measurement;
g) the immunity of other equipment in the environment. The user shall ensure that other
equipment being used in the environment is compatible. This may require additional
protection measures;
h) the time of day that welding or other activities are to be carried out.
The size of the surrounding area to be considered will depend on the structure of the building
and other activities that are taking place. The surrounding area may extend beyond the
boundaries of the premises.
Methods of reducing emissions-Public supply system
Arc welding equipment should be connected to the public supply system according to this manual
recommendations. If interference occurs, it may be necessary to takeadditional precautions such as
filtering of the public supply system. Consideration should be given to shielding the supply cable of
permanently installed arc welding equipment, in metallic conduit or equivalent. Shielding should be
electrically continuous throughout its length. The shielding should be connected to the welding power
source so that good electrical contact is maintained between the conduit and the welding power
source enclosure.
Maintenance of the arc welding equipment
The arc welding equipment should be routinely maintained according to this manual
recommendations. All access and service doors and covers should be closed and properly
fastened when the arc welding equipment is in operation. The arc welding equipment should
not be modified in any way, except for those changes and adjustments covered in this manaul. In
particular, the spark gaps of arc striking and stabilising devices
should be adjusted and maintained according to our recommendations.
Welding cables
The welding cables should be kept as short as possible and should be positioned close
together, running at or close to the floor level.
Equipotential bonding
Bonding of all metallic objects in the surrounding area should be considered. However,
metallic objects bonded to the work piece will increase the risk that the operator could receive
an electric shock by touching these metallic objects and the electrode at the same time. The
operator should be insulated from all such bonded metallic objects.
Earthing of the workpiece
Where the workpiece is not bonded to earth for electrical safety, nor connected to earth
because of its size and position, for example, ship’s hull or building steelwork, a connection
bonding the workpiece to earth may reduce emissions in some, but not all instances. Care should be
taken to prevent the earthing of the workpiece increasing the risk of injury to users or damage to other
electrical equipment. Where necessary, the connection of the workpiece to earth should be made by
a direct connection to the workpiece, but in some countries where direct connection is not permitted,
the bonding should be achieved by suitable capacitance, selected according to national regulations.
Screening and shielding
Selective screening and shielding of other cables and equipment in the surrounding area may
alleviate problems of interference. Screening of the entire welding area may be considered for
special applications.
1
Installation
warning

2
Overview
2.1
Features
- HF mode
HF TIG arc ignition system for contamination
free and easy arc starting.
- Down slope/Post flow time
Adjustable "Down Slope" and "Post Flow"
time when TIG welding.
- Extra functions
Automatic arc force, hot start & anti stick
control for greater control and easy of use in
MMA welding.
- 2T/4T trigger control
Programs provided for the optimum selection
of the Slope by the torch trigger.
- Digital display
Digital display meter for accurate setting &
feedback of welding output.
- Protections
Equipped with temperature, phase loss protection; voltage and current sensors for high protection.
- Weight
Extremely low weight and versatility.
- Generator friendly
Designed to work with diesel generators and to avoid failures due to its voltage spikes.
2.2
Technical
Data
Models
Parameters
GRAND TIG 200 DC
Power Supply Voltage (V) 1~220V/230V/240V±10%
Frequency(HZ) 50/60
Rated input current (I1max)
（
A
）
45 MMA/ 32 TIG
Rated input power（KW）7 MMA/ 5 TIG
Duty cycle (40℃10 min)
35% 200A
60% 125A
100% 100A
Welding Current Range （A）10-200
Down Slope Time (S) 0-10
Post Flow Time (S) 0-7
No Load Voltage(V) 77
Efficiency(%) ≥85%
Power Factor 0.7
Insulation class H
Protection class IP23
Cooling AF
Net Weight(Kg) 7.7
Dimensions(mm) 520*185*305
Electrode Diameter φ1.6~φ4.0
Electrode Type 6013,7018 etc.
Note: The above parameters are subject to change with future machine improvement!

2.3
Brief
Introduction GRAND TIG 200 DC adopts the latest Pulse Width Modulation (PWM) technology and the Insulated
Gate Bipolar Transistor (IGBT) power modules. It uses switching frequencies in the 20KHz-50KHz ranges
so as to replace the traditional line-frequency transformer type welding machines. Thus, machines are
characterized with portability, small size, lightweight, low energy consumption and noise, etc.
GRAND TIG 200 DC has excellent performance: constant current output makes welding arc more
stable; fast dynamic response speed reduces the impact from the arc length fluctuation to the current;
accurate stepless current adjustment and pre-setting function. There are also some automatic
protection functions for under voltage, over current, over heat, etc. inside the welder, when the
problems listed before occurred, the alarm light on the front panel is on and at the same time the
output current will be cut off. It can self-protect, prolong the usefull life, greatly improved the reliability
and practicality of the welding machine.
The parameters of the machine on the front panel all can be adjusted continuously and steplessly,
such as welding current, down slope time and post flow time etc. When welding, it takes high
frequency and high voltage for arc igniting to ensure the success ratio of igniting arc.
This machine has wide range of applications. Given its small size, light weight, easy and flexible
operation, it can be used in various kinds of environment, such as working aloft, field work, interior
decoration, etc.
TIG series of welding machines is suitable for all positions welding for various plates made of stainless
steel, carbon steel, alloyed steel, titanium, magnesium, cuprum, etc, which is also applied to pipe
installment, mould mend, petrochemical, architecture decoration, car repair, bicycle, handicraft and
common manufacture.
2.4
Duty cycle
and
Over-heat
The letter “X” stands for Duty Cycle, which is defined as the portion of the time a welding machine
can weld continuously with it’s rated output current within a certain time cycle (10 minutes).
The relation between the duty cycle “X” and the output welding current “I” is shown as the right figure.
If the welding machine is overheating, the IGBT over-heat protection sensing will send a signal to the
welding machine control unit to cut the output welding current OFF and light the over-heat pilot lamp
on the front panel. In that case, the machine should not be welding for 10-15 minutes to cool down
with the fanrunning. When operating the machine again, the welding output current or the duty cycle
should be reduced.
Relation of welding current and
duty
cycle for
GRAND TIG 200 DC

2.5
Working
Principle
2.6
Volt-Ampere
Characteristic
The working principle of GRAND TIG 200 DC is shown in the following figure. Single-phase 220V line
frequency AC is rectified into DC (about 315V), then is converted to medium frequency AC
(about 40KHz) by inverter device (IGBT), after reducing voltage by medium transformer
(the main transformer) and rectified by medium frequency rectifier (fast recovery diode), and is
outputted by inductance filtering. The circuit adopts current feedback control technology to insure
current output stability. Meanwhile, the welding current parameters can be adjusted continuously and
steplessly to meet with the requirements of welding craft.
Rectify Inverter
Medium
frequency
transformer
Medium
frequency
rectify
Hall device
Current positive-
feedback control
Three-phase, AC DC AC DC
380V，50Hz
AC DC
TIG series of welding machines has excellent volt-ampere characteristic. Referring to the following
graph. In TIG welding, the relation between the rated loading voltage U2 and welding current I2
is as follows:
When I2≤600A，U2＝10＋0.04 I2（V）； When I2＞600A，U2＝34（V）.

3
Installation
&
Operation
3.1
Layout for
the front
and rear
panel
（1）“-” Output terminal.
（2）TIG torch remote connection socket.
（3）TIG torch gas connector.
（4）“+” Output terminal.
（5）Power switch: control the power
Supply on and off.
（6）Input power cable.
（7）Inlet gas connector.
（8）TIG post gas flow control knob.*
（9）Welding output mode switch:
Sets power source in TIG 2T,
TIG 4T or MMA mode. *
（10）Down slope control knob. *
（11）Digital current display meter.
（12）Alarm light. *
（13）Power light: Lights when input power
connected and machine switched on.
（14）Welding current control knob.
*Denotes more detailed explanation of function to follow.
Further Controls Explained
Post Flow control knob
Controls the period of time the shielding gas continues to flow for after the arc is stopped. This protects
the weld area and torch tungsten from contamination while it is still hot enough to react with
atmospheric gases, after the weld is finished. Post flow time(0-7S) adjust by turning the knob when
TIG welding.
Down slope control knob
When the trigger is released, the welding current will reduce gradually over the time selected down
to 0. This allows the operator to complete the weld without leaving a ‘crater’ at the end of the
weld pool. Down slope time(0-10S) adjust by turning the knob when TIG welding.
TIG 2T/4T
In 2T mode the trigger is pulled and held on to activate the welding circuit, when the trigger is
released, the welding circuit stops. 4T is known as ‘latching’ mode. The trigger is pulled once and
released to activate the welding circuit, pulled and released again to stops the welding circuit. This
function is useful to longer welds as the trigger is not required to be held on continuously.
Alarm Indicator
Lights when over voltage, over current or electrical overheating (due to exceeding duty cycle) is
+detected and protection is activated. When protection is activated, welding output will be disabled
until the safety system senses the overload has reduced sufficiently and indicator lamp goes out. May
also trigger if machine experiences an internal power circuit failure.
The TIG series of welding machines is designed to operate on a 230V AC power supply.
When the power supply voltage is over the safe work voltage, there are over voltage and under
voltage protection inside the welder, the alarm light will on, at the same time, the current output will be
cut off.
If the power supply voltage continually goes beyond the safe work voltage range, it will shorten the
welder life-span. The below measures can be used:
- Change the power supply input net. Such as, connect the welder with the stable power supply
voltage of distributor;
- Induce the machines using power supply in the same time;
- Set the voltage stabilization device in the front of power cable input.
3.2
Power
supply
input
Connection

3.3
Installation
&
Operation
for MMA
Welding
3.3.1
Set up
installation
for MMA
Welding
Connection of Output Cables Two sockets are available on this welding machine. For MMA welding
the electrode holder is shown be connected to the positive socket, while the earth lead (work piece) is
connected to the negative socket, this is known as DCEP. However various electrodes require a
different polarity for optimum results and careful attention should be paid to the polarity, refer to the
electrode manufacturers information for the correct polarity.
DCEP: Electrode connected to “+”output socket.
DCEN: Electrode connected to“-” output socket.
(1) Connect the earth lead to “-”, tighten clockwise;
(2) Connect the earth clamp to the work piece. Contact with the work piece must be firm contact
with clean, bare metal, with no corrosion, paint or scale at the contact point.
(3) Connect the electrode lead to “+”, tighten clockwise;
(4) Each machine is equipped with a power cable should be based on the input voltage welding
power cable connected to the appropriate position, not to pick the wrong voltage;
(5) With the corresponding input power supply terminal or socket good contact and prevent
oxidation;
(6) With a multi meter measure the input voltage is within the fluctuation range;
(7) The power ground is well grounded.
2
13 14 12 11 10 9 8

3.3.2
Operation
for MMA
Welding
(1) According to the above method to install is correct, turn the power switch, so that the power
switch is “ON” position, then the power indicator light, the fan comes on, the device work properly.
(2) Select the MMA function with the 4T/2T/MMA selector switch.
(3) Set the required output current by turning the current control knob .
(4) Place the electrode into the electrode holder and clamp tight.
(5) Strike the electrode against the work piece to create and arc and hold the electrode steady to
maintain the arc.
(6) Commence welding. If necessary, readjust the welding current control knob to obtain the
welding condition required.
(7) After completion of welding the Power Source should be left turned ON for 2 to 3 minutes. This
allows the fan to run and cool the internal components.
(8) Switch the ON/OFF Switch (located on the rear panel) to the OFF position.
NOTE:
- Note the polarity of wiring, the general DC welding wire in two ways. Selected according to the
technical requirements of welding the appropriate connection, if you choose incorrectly will result
in arc instability and spatter large adhesion and other phenomena, such cases can be quickly
reversed to joints.
- If the work piece distance from the welding machine, the second line(electrode holder and
ground) is longer, so choose the appropriate conductor cross-sectional area should be larger to
reduce cable voltage drop.
One of the most common types of arc welding is manual metal arc welding (MMA) or stick welding.
An electric current is used to strike an arc between the base material and a consumable electrode
rod or ‘stick’. The electrode rod is made of a material that is compatible with the base material being
welded and is covered with a flux that gives off gaseous vapours that serve as a shielding gas and
providing a layer of slag, both of which protect the weld area from atmospheric contamination. The
electrode core itself acts as filler material the residue from the flux that forms slag covering over the
weld metal must be chipped away after welding.
● The arc is initiated by momentarily touching the electrode
to the base metal.
● The heat of the arc melts the surface of the base metal to
form a molten pool at the end of the electrode.
● The melted electrode metal is transferred across the arc
into the molten pool and becomes the deposited weld
metal.
● The deposit is covered and protected by a slag which
comes from the electrode coating.
● The arc and the immediate area are enveloped by an
atmosphere of protective gas.
3.3.3
MMA
Welding

The covering on a shielded metal arc welding electrode is
called Flux.
The flux on the electrode performs many diferent functions.
These include:
● producing a protective gas around the weld area
● providing fluxing elements and deoxidizer
● creating a protective slag coating over the weld as it
cools
● establishing arc characteristics
● adding alloying elements.
Covered electrodes serve many purposes in addition to
filler metal tothe molten pool. These additional functions
are provided mainly by the covering on the electrode.
3.3.4
MMA
Welding
trouble
shooting
The following chart addresses some of the common problems of MMA welding. In all cases of
equipment malfunction, the manufacturer’s recommendations should be strictly adhered to and
followed.
NO. Trouble Possible Reason Suggested Remedy
1 No arc
Incomplete welding circuit
Check earth lead is connected.
Check all cable connections.
No power supply
Check that the machine is switched
on and has a power supply
Wrong mode selected
Check the MMA selector switch is
selected
2
Porosity −small
cavities or holes
resulting from gas
pockets in weld
metal
Arc length too long
Shorten the arc length
Work piece dirty,
contaminated or moisture
Remove moisture and materials like
paint, grease, oil, and dirt, including
mill scale from base metal
Damp electrodes
Use only dry electrodes
3 Excessive Spatter Amperage too high
Decrease the amperage or choose a
larger electrode
Arc length too long Shorten the arc length
4 Weld sits on top,
lack of fusion
Insufficient heat input Increase the amperage or choose a
larger electrode
Work piece dirty,
contaminated or moisture
Remove moisture and materials like
paint, grease, oil, and dirt, including
mill scale from base metal
Poor welding technique
Use the correct welding technique or
seek assistance for the correct
technique
5 Lack of penetration
Insufficient heat input
Increase the amperage or choose a
larger electrode
Poor welding technique
Use the correct welding technique or
seek assistance for the correct
technique
Poor joint preparation
Check the joint design and fit up,
make sure the material is not too
thick. Seek assistance for the correct
joint design and fit up
6
Excessive
penetration - burn
through
Excessive heat input
Reduce the amperage or use a
smaller electrode
Incorrect travel speed
Try increasing the weld travel speed
7
Uneven weld
appearance
Unsteady hand, wavering
hand
Use two hands where possible to
steady up, practise your technique
8
Distortion −
movement of base
metal during
welding
Excessive heat input
Reduce the amperage or use a
smaller electrode
Poor welding technique
Use the correct welding technique or
seek assistance for the correct
technique
Poor joint preparation and or
joint design
Check the joint design and fit up,
make sure the material is not too
thick. Seek assistance for the correct

3.4
Installation
&
Operation
for TIG
Welding
3.4.1
Set up
installation
for TIG
Welding
(1) Switch the ON/OFF Switch (located on the rear panel) to OFF.
(2) Connect the earth lead to “+”, tighten clockwise;
(3) Connect the earth clamp to the work piece. Contact with the work piece must be firm contact
with clean, bare metal, with no corrosion, paint or scale at the contact point.
(4) Connect the TIG torch cable to “-”, tighten clockwise;
(5) Connect TIG torch gas connection to the TIG gas outlet and TIG torch remote plug to remote
socket，ensuring all connections are tight.
(6) Connect the gas regulator to the Gas Cylinder and connect the gas line to the Gas Regulator.
(7) Connect the gas line to the machine inlet gas connector via the quick push lock connector
located on the rear panel. Check for Leaks!
(8) Open gas cylinder valve and adjust regulator, flow should be between 5-10 l/min depending on
application. Re-check regulator flow pressure with torch valve open as static gas flow setting may
drop once gas is flowing.
(9) Each machine is equipped with a power cable should be based on the input voltage welding
power cable connected to the appropriate position, not to pick the wrong voltage;
(10) With the corresponding input power supply terminal or socket good contact and prevent
oxidation;
(11) With a multi meter measure the input voltage is within the fluctuation range;
(12) The power ground is well grounded.
NOTE:
- Secure the gas cylinder in an upright position by chaining them to a stationary support to prevent
falling or tipping.
(1) According to the above method to install is correct, turn the power switch to the “ON”
position, the power LED. light should illuminate, the fan comes on, the device work properly.
(2) Select the 2T/4T function with the4T/2T/MMA selector switch.
(3) Set the welding current (14), down slope (10) and gas post flow (8) as required.
(4) The tungsten must be ground to a blunt point in order to achieve optimum welding results. It is
critical to grind the tungsten electrode in the direction the grinding wheel is turning.
(5) Install the tungsten with approximately 3mm to 7mm sticking out from the gas cup, ensuring you
have correct sized collet.
(6) Tighten the back cap.
(7) Commence welding. If necessary, readjust the Weld Current control to obtain the welding
condition required.
(8) After completion of welding the Power Source should be left turned ON for 2 to 3 minutes. This
allows the fan to run and cool the internal components.
(9) Switch the ON/OFF Switch (located on the rear panel) to the OFF.
3.4.2
Operation
for TIG
Welding

3.4.3
TIG GUN
Control
T
IG GUN (TIG-17)
12 Pin Remote Plug Connection
3.4.4
Tig Welding
Techniques DC TIG Welding
The DC power source uses what is known as DC (direct current) in
which the main electrical component known as electrons flowin
only one direction from the negative pole (terminal) to the positive
pole (terminal). In the DC electrical circuit there is an electrical
principle at work which should always be taken into account when
using any DC circuit. With a DC circuit 70% of the energy (heat) is
always on the positive side. This needs to be understood because it
determines what terminal the TIG torch will be connected to (this
rule applies to all the other forms of DC welding as well ).
DC TIG welding is a process in which an arc is struck between a
TUNGSTEN electrode and the metal work piece. The weld area is
shielded by an inert gas flow to prevent contamination of the
tungsten, molten pool and weld area. When the TIG arc is struck
the inert gas is ionized and superheated changing it’s molecular
structure which converts it into a plasma stream. This plasma stream
flowing between the tungsten and the work piece is the TIG arc
and can be as hot as 19,000°C. It is a very pure and concentrated
arc which provides the controlled melting of most metals into a
weld pool. TIG welding offers the user the greatest amount of
flexibility to weld the widest range of material and thickness and
types. DC TIG welding is also the cleanest weld with no sparks or
spatter.

（1）“-” Output terminal.
（2）TIG torch remote connection socket.
（3）TIG torch gas connector.
（4）“+” Output terminal.
（5）Power switch: control the power
Supply on and off.
（6）Input power cable.
（7）Inlet gas connector.
（8）TIG post gas flow control knob.*
（9）Welding output mode switch:
Sets power source in TIG 2T,
TIG 4T or MMA mode. *
（10）Down slope control knob. *
（11）Digital current display meter.
（12）Alarm light. *
（13）Power light: Lights when input power
connected and machine switched on.
（14）Welding current control knob.
*Denotes more detailed explanation of function to follow.
Further Controls Explained
Post Flow control knob
Controls the period of time the shielding gas continues to flow for after the arc is stopped. This protects
the weld area and torch tungsten from contamination while it is still hot enough to react with
atmospheric gases, after the weld is finished. Post flow time(0-7S) adjust by turning the knob when
TIG welding.
Down slope control knob
When the trigger is released, the welding current will reduce gradually over the time selected down
to 0. This allows the operator to complete the weld without leaving a ‘crater’ at the end of the
weld pool. Down slope time(0-10S) adjust by turning the knob when TIG welding.
TIG 2T/4T
In 2T mode the trigger is pulled and held on to activate the welding circuit, when the trigger is
released, the welding circuit stops. 4T is known as ‘latching’ mode. The trigger is pulled once and
released to activate the welding circuit, pulled and released again to stops the welding circuit. This
function is useful to longer welds as the trigger is not required to be held on continuously.
Alarm Indicator
Lights when over voltage, over current or electrical overheating (due to exceeding duty cycle) is
+detected and protection is activated. When protection is activated, welding output will be disabled
until the safety system senses the overload has reduced sufficiently and indicator lamp goes out. May
also trigger if machine experiences an internal power circuit failure.
The TIG series of welding machines is designed to operate on a 230V AC power supply.
When the power supply voltage is over the safe work voltage, there are over voltage and under
voltage protection inside the welder, the alarm light will on, at the same time, the current output will be
cut off.
If the power supply voltage continually goes beyond the safe work voltage range, it will shorten the
welder life-span. The below measures can be used:
- Change the power supply input net. Such as, connect the welder with the stable power supply
voltage of distributor;
- Induce the machines using power supply in the same time;
- Set the voltage stabilization device in the front of power cable input.
The intensity of the arc is proportional to the current that flows
from the tungsten. The welder regulates the welding current to
adjust the power of the arc. Typically thin material requires a less
powerful arc with less heat to melt the material so less current
(amps) is required, thicker material requires a more powerful arc
with more heat so more current (amps) are necessary to melt the
material.
TIG Welding Fusion Technique
Manual TIG welding is often considered the most difficult of all the
welding processes. Because the welder must maintain a short arc
length, great care and skill are required to prevent contact
between the electrode and the work piece. Similar to Oxygen
Acetylene torch welding, Tig welding normally requires two hands
and in most instances requires the welder to manually feed a filler
wire into the weld pool with one hand while manipulating the welding torch in the other. However,
some welds combining thin materials can be accomplished without filler metal like edge, corner, and
butt joints. This is known as Fusion welding where the edges of the metal pieces are melted together
using only the heat and arc force generated by the TIG arc. Once the arc is started the torch tungsten
is held in place until a weld pool is created, a circular movement of the tungsten will assist is creating a
weld pool of the desired size. Once the weld pool is established tilt the torch at about a 75° angle and
move smoothly and evenly along the joint while fusing the materials together.
TIG Welding with Filler Wire Technique
It is necessary in many situations with TIG welding to add a filler wire into the
weld pool to build up weld reinforcement and create a strong weld. Once
the arc is started the torch tungsten is held in place until a weld pool is
created, a circular movement of the tungsten will assist is creating a weld
pool of the desired size. Once the weld pool is established tilt the torch at
about a 75° angle and move smoothly and evenly along the joint. The filler
metal is introduced to the leading edge of the weld pool. The filler wire is
usually held at about a 15° angle and fed into the leading edge of the
molten pool, the arc will melt the filler wire into the weld pool as the torch is moved forward.
Also a dabbing technique can be used to control the amount of filler wire added, the wire is fed into
the molten pool and retracted in a repeating sequence as the torch is moved slowly and evenly
forward. It is important during the welding to keep the molten end of the filler wire inside the gas shield
as this protects the end of the wire from being oxidised and contaminating the weld pool.

It is necessary in many situations with TIG welding to add a filler wire into the
weld pool to build up weld reinforcement and create a strong weld. Once
the arc is started the torch tungsten is held in place until a weld pool is
created, a circular movement of the tungsten will assist is creating a weld
pool of the desired size. Once the weld pool is established tilt the torch at
about a 75° angle and move smoothly and evenly along the joint. The filler
metal is introduced to the leading edge of the weld pool. The filler wire is
usually held at about a 15° angle and fed into the leading edge of the
molten pool, the arc will melt the filler wire into the weld pool as the torch is moved forward.
Also a dabbing technique can be used to control the amount of filler wire added, the wire is fed into
the molten pool and retracted in a repeating sequence as the torch is moved slowly and evenly
forward. It is important during the welding to keep the molten end of the filler wire inside the gas shield
as this protects the end of the wire from being oxidised and contaminating the weld pool.
3.4.5
Electrodes Tungsten Preparation
Always use DIAMOND wheels when grinding and cutting. While tungsten is a very hard material, the
surface of a diamond wheel is harder, and this makes for smooth grinding. Grinding without diamond
wheels, such as aluminium oxide wheels, can lead to jagged edges, imperfections, or poor surface
finishes not visible to the eye that will contribute to weld inconsistency and weld defects.
Always ensure to grind the tungsten in a longitudinal direction on the grinding wheel. Tungsten
electrodes are manufactured with the molecular structure of the grain running lengthwise and thus
grinding crosswise is “grinding against the grain.” If electrodes are ground crosswise, the electrons have
to jump across the grinding marks and the arc can start before the tip and wander.
Grinding longitudinally with the grain, the electrons flow steadily and easily to the end of the tungsten
tip. The arc starts straight and remains narrow, concentrated, and stable.
Electrode Tip/Flat
The shape of the tungsten electrode tip is an important process variable in precision arc welding. A
good selection of tip/flat size will balance the need for several advantages. The bigger the flat, the
more likely arc wander will occur and the more difficult it will be to arc start. However, increasing the
flat to the maximum level that still allows arc start and eliminates arc wonder will improve the weld
penetration and increase the electrode life. Some welders still grind electrodes to a sharp point, which
makes arc starting easier. However, they risk decreased welding performance from melting at the tip
and the possibility of the point falling off into the weld pool.
Electrode Included Angle/Taper
DC Welding Tungsten electrodes for DC welding should be ground longitudinally and concentrically
with diamond wheels to a specific included angle in conjunction with the tip/flat preparation. Different
angles produce different arc shapes and offer different weld penetration capabilities. In general,
blunter electrodes that have a larger included angle provide the following benefits：
• Last Longer
• Have better weld penetration
• Have a narrower arc shape
• Can handle more amperage without eroding.
Sharper electrodes with smaller included angle provide:
• Offer less arc weld
• Have a wider arc
• Have a more consistent arc
The included angle determines weld bead shape and size. Generally, as the included angle
increases, penetration increases and bead width decreases.
Tungsten
Diameter
Diameter at the
Tip - mm
Constant Included
Angle - Degrees
Current Range
Amps
Current Range
Pulsed Amps
1.0mm .250 20 05 - 30 05 - 60
1.6mm .500 25 08 - 50 05 - 100
1.6mm .800 30 10 - 70 10 - 140
2.4mm .800 35 12 - 90 12 - 180
2.4mm 1.100 45 15 - 150 15 - 250
3.2mm 1.100 60 20 - 200 20 - 300
3.2mm 1.500 90 25 - 250 25 - 350
Tungsten Electrode Preparation

3.4.6
TIG Welding
trouble
shooting
The following chart addresses some of the common problems of TIG welding. In all cases of
equipment malfunction, the manufacturer’s recommendations should be strictly adhered
to and followed.
NO. Trouble Possible Reason Suggested Remedy
1 Tungsten burning
away quickly
Incorrect Gas or No Gas
Use pure Argon. Check cylinder has
gas, connected, turned on and torch
valve is open
Inadequate gas flow
Check the gas is connected, check
hoses, gas valve and torch are not
restricted.
Back cap not fitted correctly
Make sure the torch back cap is
fitted so that the o-ring is inside the
torch body
Torch connected to DC +
Connect the torch to the DC- output
terminal
Incorrect tungsten being used
Check and change the tungsten type
if necessary
Tungsten being oxidised after
weld is finished
Keep shielding gas flowing 10–15
seconds after arc stoppage. 1 second
for each 10amps of weld current.
Tungsten melting back
into the nozzle on AC
welding
Check that correct type of tungsten is
being used. Check the balance
control is not set too high on the
balance-reduce to lower setting
2 Contaminated
tungsten
Touching tungsten into the
weld pool
Keep tungsten from contacting weld
puddle. Raise the torch so that the
tungsten is off of the work piece 2 -
5mm
Touching the filler wire to the
tungsten
Keep the filler wire from touching
the tungsten during welding, feed the
filler wire into the leading edge of
the weld pool in front of the tungsten
Tungsten melting into the
weld pool
Check that correct type of tungsten is
being used. Too much current for the
tungsten size so reduce the amps or
change to a larger tungsten
3
Porosity - poor
weld appearance
and colour
Wrong gas / poor gas flow
/gas leak
Use pure argon. Gas is connected,
check hoses, gas valve and torch are
not restricted. Set the gas flow
between 6-12 l/min. Check hoses
and fittings for holes, leaks et
Contaminated base metal
Remove moisture and materials like
paint, grease, oil, and dirt from base
metal
Contaminated filler wire
Remove all grease, oil, or moisture
from filler metal
Incorrect filler wire
Check the filler wire and change if
necessary
3.5
Operation
environment ▲ Height above sea level ≤1000 M
▲ Operation temperature range -10〜+40°C
▲ Air relative humidity is below 90 %( 20°C)
▲ Preferable site the machine some angles above the floor level, the maximum angle does
not exceed 15℃.
▲ Protect the machine against heavy rain AND against direct sunshine.
▲ The content of dust, acid, corrosive gas in the surrounding air or substance cannot exceed
normal standard.
▲ Take care that there is sufficient ventilation during welding. There must be at least 30cm
free distance between the machine and wall.

3.6
Operation
Notices ▲ Read Section PRESCRIPTIONS AND COMPLIANCE carefully before starting to use this equipment.
▲ Connect the ground wire with the machine directly.
▲ Ensure that the input is single-phase: 50/60Hz, 230V ±10%.
▲ Before operation, none concerned people should not be around the working area and especially
children. Do not watch the arc in unprotected eyes.
▲ Ensure good ventilation of the machine to improve Duty Cycle.
▲ Turn off the engine when the operation finished for energy consumption efficiency.
▲ When power switch shuts off protectively because of failure. Don’t restart it until problem is resolved.
Otherwise, the range of problem will be extended.
▲ In case of problems, contact your local dealer if no authorized maintenance staff is available!
In order to guarantee safe and proper operation of welding machines, they must be maintained
regularly. Let customers understand the maintenance procedure of welding machines. Enable
customers to carry on simple examination and inspections. Do your best to reduce the fault rate and
repair times of welding machines to lengthen service life of arc welding machine. Maintenance items
in detail are in the following table.
● Warning: For safety while maintaining the machine, please shut off the main input power
and wait for 5 minutes, until capacitors voltage already drop to safe voltage 36V!
4
Maintenance
&
Troublesho-
oting
4.1
Maintenance
Date
Maintenance items
Daily
examinati
on
Observe that the knobs and switches in the front and at the back of arc
welding machine are flexible and put correctly in place. If any knob has not
been put correctly in place, please correct. If you can't correct or fix the knob,
please replace immediately;
If any switch is not flexible or it can't be put correctly in place, please replace
immediately. Please get in touch with maintenance service department if there
are no accessories.
After turn-on power, watch/listen if the arc- welding machine has shaking,
whistle calling or peculiar smell. If there is one of the above problems, find out
the reason and clear it. If you can't find out the reason, please contact your local
service repair station or distributor/agent .
Observe that the display value of LED is intact. If the display number is not
intact, please replace the damaged LED. If it still doesn’t work, please maintain
or replace the display PCB.
Observe that the min/max values on LED agree with the set value. If there is
any difference and it has affected the normal welding results, please adjust it.
Check whether the fan is damaged and whether it is normal to rotate or
control. If the fan is damaged, please change immediately. If the fan does not
rotate after the machine is overheated, observe if there is something blocking
the blade. If it is blocked, please clear the problem. If the fan does not rotate
after getting rid of the above problems, you can poke the blade by the rotation
direction of fan. If the fan rotates normally, the start capacity should be
replaced. If not, change the fan.
Observe whether the fast connector is loose or overheated. If the arc- welding
machine has the above problems, it should be fastened or changed.
Observe whether the current output cable is damaged. If it is damaged, it
should be insulated or changed.
Monthly
examinati
on
Using the dry compressed air to clear the inside of arc welding machine.
Especially for clearing up the dusts on radiator, main voltage transformer,
inductors, IGBT modules, fast recover diodes, PCB’s, etc.
Check the screws and bolts in the machine. If any is loose, please screw it
tight. If it is shaved, please replace. If it is rusty, please erase rust on all bolts to
ensure it works well.
Quarter-
yearly
examinati
on
Check whether the actual current accords with the displaying value. If they did
not accord, they should be regulated. The actual welding current value can be
measured by and adjusted by plier-type ampere meter.
Yearly
examinati
on
Measure the insulating impedance among the main circuit, PCB and case, if it
below 1MΩ, insulation is thought to be damaged and need to change, and need
to change or strengthen insulation.

4.2
Troublesho-
oting - Before the welding machines are dispatched from the factory, they have already been tested and
calibrated accurately. It is forbidden for anyone who is not authorized by our company to do any
change to the equipment!
- Maintenance course must be operated carefully. If any wire becomes flexible or is misplaced, it
maybe potential danger to user!
- Only professional maintenance staff that isauthorized by our company could overhaul the machine!
- Be sure to shut off the Main Input Power before doing any repair work on the welding machine!
- If there is any problem and there is no authorized professional maintenance personal on site,
please contact local agent or the distributor!
If there are some simple troubles with the welding machine, you can consult the following Chart:
S/N Troubles Reasons Solution
1 Turn on the power source,and the power
lamp is on, but fan doesn’t work
There is something in the fan Clear out
The start capacitor of fan damaged Change capacitor
The fan motor damaged Change fan
2 The number on the display is not intact. The LED in the display is broken Change the LED
3 The max and min value displayed
doesn’t accord with the set value.
The max value is not accordant
Adjust potentiometer Imax on the
control board.
The min value is not accordant
Adjust potentiometer Imin the current
meter.
4 No no-load voltage output The machine is damaged Check the main circuit and the Pr4.
5 Arc can not be
ignited (TIG)
There is spark on the
HF igniting board.
The welding cable is not connected
with the two output of the welder.
Connect the welding cable to the
welder’s output.
The welding cable damaged.
Repair or change it.
The earth cable connected unstably.
Check the earth cable.
The welding cable is too long.
Use an appropriate welding cable.
There is oil or dust on the workpiece.
Check and remove it.
The distance between tungsten
electrode and workpiece is too long.
Reduce the distance (about 3mm).
There is not spark on
the HF igniting board.
The HF igniting board does not work. Repair or change Pr8
The distance between the discharger is
too short.
Adjust this distance (about 0.7mm).
The malfunction of the welding gun
switch.
Check the welding gun switch, control
cable and aero socket.
6 No gas flow (TIG)
Gas cylinder is close or gas pressure is
low Open or change the gas cylinder
Something in the valve
Remove it
Electromagnetic valve is damaged
Change it
7
Gas always flows
The gas-test on the front panel is on
The gas-test on the front panel is off
Something in the valve
Remove it
Electromagnetic valve is damaged
Change it
The adjustment knob of pre -gas time
on the front panel is damaged Repair or change it
8 The welding current can not be adjusted
The welding current potentiometer on
the front panel connection is not good
or damaged
Repair or change the potentiometer
9 The welding current displayed isn’t
accordant with the actual value.
The min value displayed isn’t
accordant with the actual value.
Adjust potentiometer Imin on the
power board.
accordant with the actual value.
Adjust pot entiometer Imax on the
power board.
10
The penetration of molten pool is not
enough.
The welding current is adjusted too
low
Increase the welding current
11 The alarm lamp on the front panel is on Over heat
protection
Two much welding
current
Reduce the welding current output
Working time too
long
Reduce the duty cycle (work
intermittently)

4.3
List of error
code
Error Type Error code Description Lamp status
Thermal relay
E01 Over-heating(1st thermal relay)
Yellow lamp(thermal
protection) always on
E02 Over-heating(2nd thermal relay)
Yellow lamp(thermal
protection) always on
E09 Over-heating(Program in default)
Yellow lamp(thermal
protection) always on
Welding
machine
E10 Phase loss
Yellow lamp(thermal
protection) always on
E13 Under voltage
Yellow lamp(thermal
protection) always on
E14 Over voltage
Yellow lamp(thermal
protection) always on
E15 Over current
Yellow lamp(thermal
protection) always on
Switch
E20
Button fault on operating panel
when switch on the machine
Yellow lamp(thermal
protection) always on
E21
Other faults on operating panel
when switch on the machine
Yellow lamp(thermal
protection) always on
E41
Communication error

4.4
Electrical
schematic
drawing

L
OKERMANN Srl,
V
ia Produzione 16/18, 37044, Cologna Veneta,
(
VR)-Italy, Tel: [phone]
l
[e-mail] - www.lokermann.eu