KEMPPI LT 250 MasterTig 12.6kg Unit Instruction Manual
- June 5, 2024
- KEMPPI
Table of Contents
MasterTig LT250
OPERATING MANUAL
PREFACE
1.1 General
Congratulations on choosing the MasterTig LT 250 equipment. Used correctly,
Kemppi products can significantly 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 specifications of the equipment can be found at
the end of the manual.
Please read the manual carefully before using the equipment for the first
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
authorized Kemppi dealer, or visit the Kemppi web site at
www.kemppi.com.
The specifications 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 effort 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 specification 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.
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.
BEFORE YOU START USING THE UNIT
NOTE! Please read the separate safety instruction booklet provided before
you commence welding.
Pay particular attention to the risks associated with fire 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 airflow in the machine is unrestricted.
2.2 Positioning and location of the machine
Place the machine on a firm, dry and level surface. Where possible, do not
allow dust or other impurities to enter the machine cooling airflow.
Preferably site the machine above floor 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 specific product. It is
important to make correct references to the serial number of the product when
making repairs or ordering spare parts.
2.5 General view of the machine
Front of machine
-
Control panel
-
Remote control connector
-
TIG torch control connector
-
Shield gas and current connector for TIG torch
-
(+) connector for electrode holder
-
(–) connector for earth cable
Markings for (+/–) poles on the machine front are embossed.
Rear of machine -
ON/OFF switch
-
Snap connector for gas
-
Shielding gas flow meter
-
Welding cables connectors from the 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.
2.6 Welding cable connections
Connect the parent power source
NOTE! LT 250 may be powered from a variety of parent welding power supply sources, providing the output voltage is 40 – 100 volts DC. The inadequate supply voltage will result in limited performance or failure to operate. Always connect both plus and minus welding cables from the parent power source to LT 250 to avoid the risk of malfunctioning or hazards.
Connect TIG torch
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 flow 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 workpiece surface and fix the earth return
clamp to the workpiece in order to create a closed and interference-free
welding circuit.
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 specifically 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 workpiece. If when igniting the arc or during
welding, the electrode sticks or freezes’ to the workpiece, 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 workpiece and start again. If this
fails, switch off the machine at the main switch and then release the
electrode after it has cooled down.
NOTE! The electrode and workpiece 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 insufficient diameter compared
to the welding current will melt, while excessive electrode size will make it
more difficult to ignite the arc.
Generally speaking, a 1.6 mm tungsten electrode will cover currents up to 150
A, and a 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 workpiece
during welding, re-sharpen the electrode.
3.2 Shielding gas
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
flow rate is approximately 8 – 12 liters per minute, but this can vary
according to the welding current used and the size of the 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 flow rates can be adjusted.
NOTE! Never attempt to connect directly to a compressed gas cylinder. Always use an approved and tested regulator and flow meter.
Connecting the gas hose to a typical welding regulator control valve
- Connect the supplied shielding gas hose to the machine and via a suitable coupling to the gas regulator control valve outlet and tighten the connector.
- Open the valve of the bottle.
- Measure the flow.
- Adjust the flow 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.
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 filler material and coating will melt properly and
the welding is efficient. The table below presents the electrode sizes
available for use with the MasterTig LT 250 welding machine and the
corresponding welding current values.
MMA Electrodes and corresponding current settings range
Electrode diameter| 1.6 mm| 2.0 mm| 2.5 mm| 3.25 mm|
4.0 mm| 5.0 mm
---|---|---|---|---|---|---
Fe-Rutile| 30 – 60 A| 40 – 80 A| 50 – 110 A| 80 – 150 A| 120 – 210| 150 – 250
A
Fe-Basic| 30 – 55 A| 50 – 80 A| 80 – 110 A| 110 – 150 A| 140 – 200| 200 – 250
A
3.4 Operating functions
- Machine ’ON’ green light
- Pre/Post gas, upslope/downslope, and main current parameter indicator.
- Welding parameter selector arrow keys.
- Welding process selection button (MMA or TIG).
- 2T or 4T TIG torch switch selection button. Select 2T for short welds or 4T for long welds.
- Ignition method selection button.
- Current adjustment selector: panel control, TIG Torch remote or foot pedal or hand remote.
- Welding current and parameter value control knob.
- Welding current and parameter value display: time and amperes.
- 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 flow into and out of 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.
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 the remote control with a
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.
3.4.3 TIG welding function
Select the TIG welding process by pressing the MMA/TIG button.
Torch switch control in 2T mode and HF arc ignition
The shielding gas starts to flow 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 specified 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 flow 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
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 workpiece. Press the torch trigger
and then quickly lift the contact of the tungsten electrode from the workpiece
(2T function); the arc is established simultaneously and effectively.
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 flows and the HF (High-Frequency arc) ignites
the welding arc.
Setting parameters
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 a normal state and shows the welding current value.
SETUP FEATURES
Configuring 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 controls knob. The
following parameters and values are available:
Name displayed| Parameter values| Factory setting|
Description
---|---|---|---
A| 1/0| 0| End current level selection, 1 = I min. / 0 = 15 %
C| 1/0| 0| Forced stop during downslope with a brief pressing of the switch, 1
= On / 0 = Off
d| 0/5| 0| 0 =Standard 4T switching logic / 5 = PROTIG TL switching logic
E| 5 % – 40 %| 20 %| Upslope start current level selection (% of the welding
current)
F| 1/0| 0| Restore factory settings ), 1 = Restore / 0 = No restore
h| 0.0 – 2.0 s| 0| Minimum setting for pre-gas time
J| 0 – 10 s| 1 s| Minimum setting for post-gas time
L| 5 – 20 s| 10 s| Maximum setting for pre-gas time
o| 15 – 99 s| 30 s| Maximum setting for post-gas time
S| -3…5| 0| Arc dynamics (Arc Force)
t| -9…0| 0| Electrode ignition pulse (-9 = No pulse / 0 = Max pulse)
U| 1/0| 0| Disable automatic remote control recognition.
0 = Enable automatic recognition, 1 = Disable automatic recognition.
) Happens when exiting SETUP mode and value is 1.
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 authorized Kemppi service agent and report the error
code shown.
5.1 Troubleshooting
Problem
|
Cause
---|---
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 affect 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 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 flow 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 off. Allow the unit to cool and the machine will soon automatically reset and allow welding to re-start.
• Ensure that cooling air has unrestricted flow.
• If the machine’s duty cycle has been exceeded, wait for the indicator to
turn off.
In certain circumstances, this light may also indicate irregularity in the supply voltage. Too low or high supply voltage.
MAINTENANCE
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 authorized Kemppi service agent will inspect and clean your machine,
ensuring that all power connections are tight and secure. Power connections
can become loose and oxidized 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 the TIG torch’s electrode. Replace or sharpen, if necessary.
- Check the 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 the 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 center, per the instructions of local authorities or a
Kemppi representative. By
By applying this European Directive you will improve the environment and human
health.
ORDERING NUMBERS
| Product | Part number |
|---|---|
| Mastering LT 250 | 6115100 |
Cables
Welding cable, 35 mm² 5 m| 6184301
Welding cable, 35 mm² 10 m| 6184302
Earth return cable, 35 mm² 5 m| 6184311
Earth return cable, 35 mm² 10 m| 6184312
Extension cable, 35 mm² 5 m| 6183305
Extension cable, 35 mm² 10 m| 6183310
Ancillary devices
TIG welding torch controls
RTC 10| 6185477
RTC 20| 6185478
Gas flow gauge AR/clock| 6265136
Shielding gas hose (4.5 m)| W001077
Carrying strap| 9592160
Remote control units
R 10, length 5 m| 6185409
R 10, length 10 m| 618540901
R11F| 6185407
TECHNICAL DATA
MasterTig LT 250
Connection voltage range| DC| 40 V – 100 V
Rated input power| | 8.6 kW/9.1 kVA
Supply current, I 1max| TIG| 155 A
| MMA| 230 A
Supply current, I 1eff| TIG| 90 A
| MMA| 135 A
Connection cable| | 35 mm²
Output 40 °C| TIG| 35 % ED 250 A/20 V
| TIG| 60 % ED 200 A/18 V
| TIG| 100 % ED 160 A/16.4 V
| MMA| 35 % ED 250 A/30 V
| MMA| 60 % ED 200 A/28 V
| MMA| 100 % ED 160 A/26.4 V
Welding range| TIG| 5 A/1 V – 250 A/35 V
| MMA| 10 A/1 V – 250 A/35 V
Open circuit voltage| | 90 V
Idle power| TIG| 8 W
| MMA| 21 W
Efficiency at 100 % ED| TIG| 80 %
| MMA| 86 %
Arc striking voltage| | 10 kV
MMA welding electrodes| | 1.6 – 5.0 mm
External dimensions (L × W × H)| | 460 × 180 × 390 mm
Weight| | 12.6 kg
Temperature class| | F
Degree of protection| | IP23S
EMC class| | A
Operating temperature range| | –20 °C … +40 °C
Storage temperature range| | –40 °C … +60 °C
Standars
IEC 60974-1:2012
IEC 60974-10:2007
IEC 60974-3:2007
For connection options of all gun and torch models and corresponding remote controls, refer to Kemppi Userdoc at https://kemp.cc/connectivity.
References
Read User Manual Online (PDF format)
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