8. Technical data ............................................................................................16
2
MasterTig LT 250
1. PREFACE
1.1 General
Congratulations on choosing the MasterTig LT 250 equipment. Used correctly, Kemppi products
can signicantly increase the productivity of your welding and provide years of economical service.
This operating manual contains important information on the use, maintenance and safety of your
Kemppi product. The technical specications of the equipment can be found at the end of the
manual.
Please read the manual carefully before using the equipment for the rst time. For your own safety
and that of your working environment, pay particular attention to the safety instructions in the
manual.
For more information on Kemppi products, contact Kemppi Oy, consult an authorised Kemppi
dealer, or visit the Kemppi web site at www.kemppi.com.
The specications presented in this manual are subject to change without prior notice.
Important notes
Items in the manual that require particular attention in order to minimise damage and personal
harm are indicated with the ’NOTE!’ notation. Read these sections carefully and follow their
instructions.
Disclaimer
While every eort has been made to ensure that the information contained in this guide is accurate
and complete, no liability can be accepted for any errors or omissions. Kemppi reserves the right
to change the specication of the product described at any time without prior notice. Do not copy,
record, reproduce or transmit the contents of this guide without prior permission from Kemppi.
EN
1.2 Product introduction
MasterTig LT 250 is a high quality DC TIG and MMA welding source for industrial applications.
MasterTig LT 250 requires no mains input voltage supply and is powered from the supply voltage
provided by a parent power source. See item 2.3.
Before using or doing any maintenance work on the machine, read the operating manual and keep
it for further reference.
NOTE! Please read the separate safety instruction booklet provided before you commence welding. Pay
particular attention to the risks associated with re and explosion.
2.1 Unpacking
Always before using the equipment, make sure it was not damaged during transportation. Also
check that you have received what you ordered and that there are instructions for it.
The packaging material of the products is suitable for recycling.
Transportation
The machine should be transported in an upright position.
NOTE! Always move the welding machine by lifting it from the handle. Never pull it from the welding
torch or other cables.
Environment
The machine is suitable for both indoor and outdoor use, but it should be protected from rain and
sunshine. Store the machine in a dry and clean environment and protect it from sand and dust
during use and storage. The recommended operating temperature range is -20 °C – +40 °C. Place
the machine in such a way that it does not come in contact with hot surfaces, sparks and spatters.
Make sure the air ow in the machine is unrestricted.
2.2 Positioning and location of the machine
Place the machine on a rm, dry and level surface. Where possible, do not allow dust or other
impurities to enter the machines cooling air ow. Preferably site the machine above oor level; for
example on a suitable carriage unit.
Notes for positioning the machine
• The surface inclination should not exceed 15 degrees.
• Ensure the free circulation of the cooling air. There must be at least 20 cm of free space in
front of and behind the machine for cooling air to circulate.
• Protect the machine against heavy rain and direct sunshine.
NOTE! The machine should not be operated in the rain as the protection class of the machine, IP23S,
allows for outside preserving and storage only.
NOTE! Never use a wet welding machine.
NOTE! Never aim metallic grinding spray/sparks towards the equipment.
2.3 Power supply connection
MasterTig LT 250 requires no mains input voltage supply and is powered by the supply output
voltage from a parent welding power source. You can use either a Constant Current (CC) or
Constant Voltage (CV) parent power source normally used for MMA or MIG/MAG welding, or a
welding generator with a suitable output characteristic.
NOTE! The performance of the parent power source can limit the maximum output of MasterTig LT 250.
2.4 Serial number
Serial number of the machine is marked on the rating plate. The serial number is the only proper
means of identifying parts for a specic product. It is important to make correct reference to the
serial number of the product when making repairs or ordering spare parts.
4
MasterTig LT 250
2.5 General view of the machine
7.
1.
2.
3.
4.
5.6.
Front of machine
1. Control panel
2. Remote control connector
3. TIG torch control connector
4. Shield gas and current connector for TIG torch
5. (+) connector for electrode holder
6. (–) connector for earth cable
Markings for (+/–) poles on the machine front are embossed.
8.
9.
10.
EN
Rear of machine
7. ON/OFF switch
8. Snap connector for gas
9. Shielding gas ow meter
10. Welding cables connectors from parent source
NOTE! MasterTig LT 250 is polarity protected. If the +/- power cables are connected in reverse the
machine will not function. This is evident by no power to the control panel.
NOTE! LT 250 may be powered from a variety of parent welding power supply sources, providing the
output voltage is 40 – 100 volts DC. Inadequate supply voltage will result in limited performance or
failure to operate. Always connect both plus and minus welding cables from parent power source to
LT 250 to avoid risk of malfunctioning or hazard.
Connect TIG torch
6
The welding torch is used to supply shielding gas and electrical arc energy to the weld piece. When
you press the welding torch switch, the shielding gas begins to ow and the arc is established. The
TIG torch is connected as shown.
Earth return cable
Connect the earth return cable to the positive pole in TIG welding and to the negative pole in MMA
welding.
Before you start welding, clean the work piece surface and x the earth return clamp to the work
piece in order to create a closed and interference free welding circuit.
MasterTig LT 250
3. USE
NOTE! Welding fumes may be dangerous to your health. Ensure that there is ample ventilation during
welding! Never look at the arc without a face shield specically designed for arc welding! Protect
yourself and your surrounding area from the arc and hot welding spatter!
Prepare to weld
NOTE! Always wear protective clothing, gloves, face and eye shields suitable for welding. It is
recommended that you make practice welds before you commence welding your main work piece. If
when igniting the arc or during welding, the electrode stick’s or freezes’ to the work piece, note that it
will quickly heat up, and may start to glow red hot. To release the electrode, twist the electrode holder
away from the work piece and start again. If this fails, switch o the machine at the main switch and
then release the electrode after it has cooled down.
NOTE! The electrode and work piece will be very hot. Protect yourself and others at all times.
You can start welding after you have made the necessary preparation described throughout these
instructions.
3.1 TIG welding
TIG welding electrodes and gas nozzles
In DC TIG welding we recommend the use of the WC20 (grey) type electrode, however other types
are available.
The welding electrode size (diameter) is selected depending on the welding current/power to be
used. An electrode with an insucient diameter compared to the welding current will melt, while
excessive electrode size will make it more dicult to ignite the arc.
Generally speaking, a 1.6 mm tungsten electrode will cover currents up to 150 A, and 2.4 mm
tungsten electrode up to 250 A DC current.
Before use, grind the tungsten electrode to a sharp point at approximately 1.5 times the diameter
of the electrode. If the electrode touches the work piece during welding, re-sharpen the electrode.
In TIG welding, shielding gas is used to prevent atmospheric contamination of the molten weld
pool. Normally, the shielding gas is argon (Ar), and the gas ow rate is approximately 8 – 12 litres
per minute, but this can vary according to the welding current used and the size of gas nozzle.
The machine is delivered with a 4.5 m long shielding gas hose. Connect the supplied female snap
connector of the shielding gas hose to the machine’s male hose connector, max. connection
pressure 500 kPa (5 bar). Connect the free end of the shielding gas hose to the gas bottle, via a
suitable and approved single stage regulator valve, where outlet ow rates can be adjusted.
NOTE! Never attempt to connect directly to a compressed gas cylinder. Always use an approved and
tested regulator and ow meter.
Connecting the gas hose to a typical welding regulator control valve
1. Connect the supplied shielding gas hose to machine and via a suitable coupling to the gas
regulator control valve outlet and tighten the connector.
2. Open the valve of the bottle.
3. Measure the ow.
4. Adjust the ow by the knob (8 – 12 l/min).
NOTE! Use a suitable shielding gas for the welding application. Always secure the gas cylinder in an
upright position with either a specially made wall rack or cylinder trolley. Always close the cylinder valve
after welding.
8
MasterTig LT 250
3.3 Connection for MMA welding
Electrode holder and earth clamp
In MMA welding, the welding electrodes must be connected to the correct pole. Normally, the
electrode holder is connected to the positive and the earthing cable to the negative connector.
It is also important to properly adjust the welding current so that the ller material and coating will
melt properly and the welding is ecient. The table below presents the electrode sizes available for
use with the MasterTig LT 250 welding machine and the corresponding welding current values.
EN
MMA Electrodes and corresponding current settings range
Electrode diameter1.6 mm2.0 mm2.5 mm3.25 mm4.0 mm5.0 mm
2. Pre/Post gas, upslope/downslope and main current parameter indicator.
3. Welding parameter selector arrow keys.
4. Welding process selection button (MMA or TIG).
5. 2T or 4T TIG torch switch selection button. Select 2T for short welds or 4T for long welds.
6. Ignition method selection button.
7. Current adjustment selector: panel control, TIG Torch remote or foot pedal or hand remote.
8. Welding current and parameter value control knob.
9. Welding current and parameter value display: time and amperes.
10. Overheating indicator.
Switching the machine on
When you power on the machine, the green standby indicator and panel are lit. Make sure that
there is enough space around the machine to allow the air to freely circulate and ow into and out
o the machine. If the supply cables at the back of the LT 250 are connected in reverse order the
machine will not work and the panel will not illuminate.
8.
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10
3.4.1 Welding current regulation and remote control
The welding current can be adjusted steplessly with the control knob, if panel adjustment (PANEL)
is selected.
If you want to adjust the welding current with the remote control, connect the remote control to
the machine and then select remote control with selector (7). The following remote control options
are available: RTC10, RTC20, R10 and R11F. The remote foot pedal R11F can only be used with TIG
welding in 2T operation mode.
3.4.2 MMA welding settings
MMA welding is selected when the indicator next to the MMA symbol is lit. If needed, press the
process selection button to select the MMA process (4). The machine automatically sets suitable
values to the ignition time, ignition pulse and arc dynamics.
MasterTig LT 250
3.4.3 TIG welding function
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W006859
Select the TIG welding process by pressing the MMA/TIG button.
Torch switch control in 2T mode and HF arc ignition
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The shielding gas starts to ow when the torch switch is pressed and the welding arc is established
automatically via HF ignition. The current starts to rise (if an upslope time is established) to the
set welding current level. When you release the switch, the current starts to decrease. After the
specied downslope time, the arc is disconnected and the set post-gas time begins.
Torch switch control in 4T mode and HF arc ignition
The shielding gas starts to ow when the torch switch is pressed. When the switch is released,
the arc is automatically established via HF ignition. The current starts to rise (if an upslope time
is established) to the set welding current level. When ready to end the welding cycle, press
and release the torch switch again. The welding current starts to drop (if a downslope time is
established) until the arc is extinguished and the set post-gas time begins.
HF or Contact ignition
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The TIG arc can be established with or without an HF pulse.
If the HF indicator is not lit, the arc can be established by lightly contacting the tungsten electrode
to the work piece. Press the torch trigger and then quickly lift the contact of the tungsten electrode
from the work piece (2T function); the arc is established simultaneously and eectively.
For HF ignition, press the HF button so that the indicator is on (item 6). Press the TIG torch trigger
and hold or release, depending on whether 2T or 4T is selected. The shielding gas ows and the HF
(High Frequency arc) ignites the welding arc.
Select the welding parameters with the arrow keys (3) and adjust the parameter values with the
control knob (8). When setting the parameters, the display (9) will show the parameter being
adjusted as well as the numeric value that will be set for it. After three seconds, the display returns
to normal state and shows the welding current value.
4. SETUP FEATURES
Conguring additional features
The machine has additional features that can be selected and adjusted with the SETUP feature. To
activate and deactivate it, press both arrow buttons (3) simultaneously for at least 5 seconds.
In the SETUP mode, the display will show the name of the parameter to be adjusted and its
numerical value. Select the parameter to be adjusted with the arrow buttons and change the
parameter value with the control knob. The following parameters and values are available:
Name
displayed
A1/00End current level selection, 1 = I min. / 0 = 15 %
C1/00Forced stop during downslope with a brief pressing of the switch,
d0/500 =Standard 4T switching logic / 5 = PROTIG TL switching logic
E5 % – 40 %20 %Upslope start current level selection (% of the welding current)
F1/00Restore factory settings *), 1 = Restore / 0 = No restore
h0.0 – 2.0 s0Minimum setting for pre-gas time
J0 – 10 s1 sMinumum setting for post-gas time
L5 – 20 s10 sMaximum setting for pre-gas time
o15 – 99 s30 sMaximum setting for post-gas time
S-3...50Arc dynamics (Arc Force)
t-9...00Electrode ignition pulse (-9 = No pulse / 0 = Max pulse)
U1/00Disable automatic remote control recognition. 0 = Enable automatic
*) Happens when exiting SETUP mode and value is 1.
Parameter
values
Factory
setting
Description
1 = On / 0 = O
recognition, 1 = Disable automatic recognition.
12
MasterTig LT 250
5. ERROR CODES
The machine always checks its operation automatically during start-up and reports any failures
detected. If failures are detected during start-up, they are shown as error codes on the control
panel display.
Error 4: Power source overheating
The power source has overheated. The cause may be one of the following:
• The power source has been used for a long time at maximum power.
• The circulation of cooling air to the power source is blocked.
• The cooling system has experienced a failure.
Remove any obstacle to air circulation, and wait until the power source fan has cooled down the
machine.
Other error codes:
The machine can show codes not listed here. In the event of an unlisted code appearing, contact
an authorised Kemppi service agent and report the error code shown.
5.1 Troubleshooting
ProblemCause
Panel display does not light. • Check parent power supply is functioning
• Check parent power supply is connected
• Check parent power supply cable connectors are correct and secure.
Poor welding results. Several factors aect the welding quality.
• Ensure that the parent power source is set to full power and that the voltage exceeds
the minimum supply voltage level of 40 volts. (Inadequate supply voltage will result
in an unstable power delivery or poor ignition).
• Ensure that the welding current selected is adequate for the selected electrode type
and size.
• Ensure the cable connections are correct and secure.
• Ensure the process selection is correct.
• Check that the earth return clamp connection area is clean and that the cable and
clamp are not damaged.
• For TIG welding, check that the shielding gas ow is switched on and set correctly.
Poor ignition and arc quality in TIG welding may be a result of a poorly prepared
tungsten electrode. Always maintain and grind a point on the TIG torch electrode tip
before welding.
Overheating indicator is illuminated. Normally, this indicates that the device has reached its maximum designed operating
temperature. The thermostat has become active, switching the welding power o.
Allow the unit to cool and the machine will soon automatically reset and allow
welding to re-start.
• Ensure that cooling air has unrestricted ow.
• If the machine’s duty cycle has been exceeded, wait for indicator to turn o.
In certain circumstances, this light may also indicate irregularity in the supply voltage.
Too low or high supply voltage.
If the machine’s malfunction is not eliminated with the above measures, contact Kemppi service.
All electromechanical devices require routine service maintenance depending on usage. This type
of routine maintenance will prevent hazards and malfunctions.
We recommend that you schedule a service inspection of your welding machine every six months.
An authorised Kemppi service agent will inspect and clean your machine, ensuring that all power
connections are tight and secure. Power connections can become loose and oxidised with frequent
and high changes in temperature.
NOTE! Disconnect the machine from the power supply before handling electric cables.
NOTE! Be careful when handling electric cables!
In maintaining the unit, take into consideration the rate of use and the environment it is used in.
When the unit is used properly and serviced regularly, you will avoid unnecessary disturbances in
use and production.
6.1 Daily maintenance
Perform the following maintenance daily:
• Clean electrode holder and TIG torch’s gas nozzle. Replace damaged or worn parts.
• Check TIG torch’s electrode. Replace or sharpen, if necessary.
• Check tightness of welding and earth cables connections.
• Check the condition of the parent and welding supply cables and replace damaged cables.
• See that there is enough space around the unit for ventilation.
6.2 Storage
Store the unit in a clean and dry place. Shield it from rain, and in temperatures exceeding +25 °C
from direct exposure to sun.
6.3 Disposal of the machine
Do not dispose of electrical equipment with normal waste!
In observance of European Directive 2002/96/EC on waste electrical and electronic
equipment, and its implementation in accordance with national law, electrical equipment
that has reached the end of its life must be collected separately and taken to an
appropriate environmentally responsible recycling facility.
The owner of the equipment is obliged to deliver a decommissioned unit to a regional
collection centre, per the instructions of local authorities or a Kemppi representative. By
applying this European Directive you will improve the environment and human health.
35 mm²
TIG35 % ED 250 A/20 V
TIG60 % ED 200 A/18 V
TIG100 % ED 160 A/16.4 V
MMA35 % ED 250 A/30 V
MMA60 % ED 200 A/28 V
MMA100 % ED 160 A/26.4 V
TIG5 A/1 V – 250 A/35 V
MMA10 A/1 V – 250 A/35 V
90 V
TIG8 W
MMA21 W
TIG80 %
MMA86 %
10 kV
1.6 – 5.0 mm
460 × 180 × 390 mm
12.6 kg
F
IP23S
A
–20 °C … +40 °C
–40 °C … +60 °C
16
MasterTig LT 250
KEMPPI OY
Kempinkatu 1
PL 13
FIN-15801 LAHTI
FINLAND
Tel +358 3 899 11
Telefax +358 3 899 428
export@kemppi.com
www.kemppi.com
LAKSHMI TOWERS
New No. 2/770,
First Main Road,
Kazura Garden,
Neelankarai,
CHENNAI - 600 041
TAMIL NADU
Tel +91-44-4567 1200
Telefax +91-44-4567 1234
sales.india@kemppi.com
KEMPPI WELDING SOLUTIONS SDN BHD
No 12A, Jalan TP5A,
Taman Perindustrian UEP,
47600 Subang Jaya,
SELANGOR, MALAYSIA
Tel +60 3 80207035
Telefax +60 3 80207835
sales.malaysia@kemppi.com
1910100
1422
www.kemppi.com
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