Lincoln Electric Expressweld MasterMIG 250CT User manual

Eczacıbaşı - Lincoln Electric recommend to use “ASKAYNAK” gas metal arc
welding wire for obtaining high performance from MasterMIG 250CT.
www.askaynak.com.tr
Expressweld Model : MasterMIG 250CT
Gas Metal Arc Welding Machine
USER MANUAL
GMAW (MIG/MAG)
Welding Method and Specifications
CO
235%
Phase

AT - UYGUNLUK BEYANI
EU - DECLARATION of CONFORMITY
EU - KONFORMITÄTSERKLÄRUNG
Déclaration de Conformité de l'EU
KAYNAK TEKNİĞİ SANAYİ ve TİCARET A.Ş.
Şirket / Firm / Firma / Société
aşağıda modeli belirtilen kaynak makinesinin
declares that the welding machine
erklärt, daß die Bauart der Maschine
déclare que le poste de soudage
® ®
EXPRESSWELD MasterMIG 250CT
aşağıda belirtilen yönergelere uygun olduğunu
conforms to the following directives
den folgenden Bestimmungen entspricht
est conformé aux directives suivantes
2004/108/EC, 2006/95/EC
ve yine aşağıda belirtilen normlara uygun olarak tasarlandığını beyan eder.
and has been designed in compliance with the following standards
und in Überienstimmung mit den nachstehenden normen hergestellt wurde
et qu'il a été conçu en conformité avec les normes
TS EN 60974-1:2007, TS EN 60974-10:2009
Pazarlama ve Lojistik Müdürü / Marketing and Logistics Manager / Directeur de Marché et Logistiques
Sertaç ÖZEN
22.03.2010Tarih / Date / Datum / Date :
Kaynak Tekniği Sanayi ve Ticaret A.Ş.
TOSB Otomotiv Yan Sanayi İhtisas Organize Sanayi Bölgesi
2. Cadde, No: 5, Şekerpınar 41480 Çayırova, Kocaeli - TURKEY

1. General Safety Rules
Electromagnetic Compatibility
2. General Information, Warnings and Operation Conditions
3. Specifications
4. Technical Data
5. Front Panel Controls
6. Back Panel Controls
7. Controls in Wire Feeder System
8. Connection Diagram
9. Installation and Operation of Machine
9.1. Mains Supply
9.2. Shielding Gas Connection
9.3. Welding Torch Connection
9.4. Connecting Shielding Gas Cylinder to Welding Machine
9.5. Installing Welding Wire
10. Functions of Wire Feeder System
11. GMAW (MIG/MAG) Method
12. Environment Conditions
13. Efficient Use of Machine In Terms of Energy Consumption
14. Storage and Transportation
15. Unpacking
16. Expirty of Machine's Physical Life
17. Maintenance and Repair
18. Troubleshooting Guide
19. Failures in Welding Seams
20. Spare Part List
21. Electrical Circuit Diagram
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39
Table of Contents
December 2014
Kaynak Tekniği Sanayi ve Ticaret A.Ş.
TOSB Otomotiv Yan Sanayi İhtisas Organize Sanayi Bölgesi
2. Cadde, No: 5, Şekerpınar 41480 Çayırova, KOCAELİ
Phone: [phone] Fax: [phone]
www.askaynak.com.tr
MANUFACTURER
Manufactured in People's Republic of China by KAYNAK
TEKNİĞİ SANAYİ ve TİCARET A.Ş.
Physical life determined by Ministry of Industry and Trade is 10 years.
(This is the period for providing spare parts required for the machine to operate.)
Expressweld MasterMIG 250CT
21. Warning and Specifications of Welding Machine 40

"Expressweld"
is the registered trademark of Kaynak Tekniği
Sanayi ve Ticaret A.Ş.
Expressweld MasterMIG 250CT

"MasterMIG"
is the registered trademark of Kaynak Tekniği
Sanayi ve Ticaret A.Ş.
Expressweld MasterMIG 250CT

Page 1
1 General Safety Rules
Expressweld MasterMIG 250CT
THIS MACHINE HAS BEEN DESIGNED FOR GMAW (MIG/
MAG). SHALL NOT BE USED FOR ANY OTHER PURPOSE.
READ AND UNDERSTAND THE INSTRUCTIONS CAREFULLY:
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WARNING: This symbol indicates that the instructions within the user guide
must be followed to avoid potential serious personal injury, loss of life and
damages on machine. Protect yourself and other people.
Be sure that this machine should only operated by qualified personnel.
Be sure that all installation, operation, maintenance and repair
procedures are performed only by authorized personnel. Be sure to read
user guide carefully before operating the machine. Failure to follow the
instructions included in the user guide may cause serious injury, loss of
life and damage on machine. Please read the warnings next to the
symbols stated below. "Kaynak Tekniği Sanayi ve Ticaret A.Ş." is not
liable for any damages due to improper connection, storage conditions
and operation procedures.
Be sure to read and understand the user guide before
operating the machine. Failure to follow the instructions stated
in the user guide may cause serious injury, loss of life and
damage on equipment.
Do not weld while you are unattentive, unattentive, tired and sleepless.
Arc welding is a safe application when necessary measures are taken to protect the
welder against potential dangers. If these measures missed or disregarded, there
may be dangers such as electric shock, exposing to high levels of fume and gas, arc
radiation, fire and explode which may cause serious injury or even death.
Note: For detailed information on safety in welding, please read ANSI Z49.1 standard.
Protective Equipments:
Welding operators should wear protective clothing to protect themselves against
burning risk. Welding burns is a frequent risk which may be caused due to splash of
welding sparks on bare skin.
Clothing used while welding may vary based on used welding method but generally it
should provide easy movements and should cover welder's body to protect against
splashes, sparks and arc radiation.

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Expressweld MasterMIG 250CT
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Flame resistant clothing,
Gaiters,
Aprons,
Leather cuff gloves and capes,
Helmet used under the welding mask.
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Noise:
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Importance and Cleanliness of Working Environment:
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Wool y clothing should be preferred due to its resistance against flame. Synthetic clothing
should not be worn since they will melt when exposed to heat.
Protective clothing should be protected from grease and oil. This kind of materials may
flare and burn uncontrolledly in an environment with oxygen.
Shirtsleeves and trouser hems should not be folded. Since sparks and melted metals
may enter into these folds. Trousers should be kept outside the work shoes and should
not be inserted into it. Otherwise melted metals and sparks may enter into shoe.
Other protective clothing used in dangerous situations are stated below:
To protect hands against burns, cuts and scratches, gloves made from flame resistant
materials such as leather must be used. In addition, to provide some insulation against
electric shock, care should be taken that the gloves made from flame resistant material
are in good condition and dry.
To protect ears against sparks and melted metals and to prevent hearing impairment due
to noise of arc welder, ear protectors should be used. When the noise in working
environment is reached to a level that disturbing the ears and causing headache, auditory
problem may occur. In such a condition immediately use your ear protectors.
Hearing impairment may not be noticed until tested and then it may be too late for
treatment.
The tidiness and cleanliness of working environment is important as the maintenance of
welder. Even the level of potential damage rises up to number of people in the
environment. Although warnings related to machine are read and necessary measures
are taken, any of the personnel tripping over a cable may cause electric shock, contact to
hot metal or falling risk for himself, you and other people.

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Expressweld MasterMIG 250CT
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Electric shock risk related to welding machine divides into two categories:
Primary voltage shock (e.g. 230-460 V)
Secondary voltage shock (e.g. 20-100 V)
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ELECTRIC SHOCK can kill.
All equipment, cables, hoses and gas cylinders should be kept away from busy places
such as doors, aisles and stairs. Care should be taken for the tidiness of the environment
and when welding is completed working environment should be cleaned. By this way,
both work safety and working efficiency will increase. Besides, other workers near the
welding area may step into weld pool by mistake, therefore safety guards should be
placed around the welding area during welding.
Electric shock danger is the most serious risk that operator may encounter frequently.
Contacting electrically hot parts may cause injuries, death or falling down due to electric
shock and sudden reflex. While machine is operating, do not touch to the electrode,
ground connection or live work piece connected to the machine. Insulate yourself against
electrode, grounding connection or work piece. Immediately after plugging out the power
cable, do not touch metal ends of power cable, there may be electric shock danger.
Primary electric shock is very dangerous since it is much higher than welding voltage.
When the power to the machine is open, you can encounter with primary electric
shock while your body is in contact with ground or touching a live point within the
machine. Please note that turning off the ON/OFF switch located on the machine do
not cut off the electric. To cut off the electric to the machine it is necessary to
disconnect the supply cable from connection point or to shut down the fuse of
incoming electric.
Never remove side covers of the machine and in case of failure have an authorized
technician to inspect and repair it.
Be sure to ground the machine and work piece.
While installing the machine and making ground connection, follow general electric
rules, all local laws and regulations and instructions of the manufacturer company.
Do not use uninsulated cables and pliers, replace with the new ones. Never dip the
electrode in water for cooling.

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Expressweld MasterMIG 250CT
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Welding Arc and Arc Rays can burn.
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Never simultaneously touch electrically "hot" parts of electrode holders connected to two
separate welders, because voltage between the two can be the total of the open circuit
voltage of both welders.
When working above floor level, use a safety belt to protect yourself from a fall should you
get a shock.
In semi-automatic or automatic welding, welding wire, electrode reel, welding head,
nozzle or torch are also electrically “hot”.
Always be sure the work cable makes a good electrical connection with the metal being
welded. The connection should be as close as possible to the area being welded.
While the welder is electrically hot, do not insert your hand or any other object inside it.
Use a shield with proper filter and cover plates to protect your eyes from sparks and the
rays of the arc when welding or observing open arc welding. Skin should be protected by
clothing made from flame resistance material. Protect other nearby personnel with
suitable, non-flammable screening and/or warn them not to watch welding arc nor expose
themselves to the arc rays or to hot spatter or metal.
When eyes are exposed to UV rays even for a short time, also called as “Getting Welder's
Flash”, it may cause burns in your eyes. Getting Welder's Flash may not be noticed after
hours of exposing, but it is too irritating as well as may cause transient blindness. Normally
getting welder's flash is a temporary situation, but exposing eyes to UV rays for a long time
and frequently may cause permanent damage on eyes. As a protection measure besides
not to watch arc rays, also using welding goggles having proper filter is necessary.
As a rule, welding should start with a dark colored protective filter then should continue
with a lighter colored filter sufficient to see the area being welded providing that not to fall
under the minimum level. Welding masks protect head, face, ears and neck against
electric shock risk, heat, sparks and fire.

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Expressweld MasterMIG 250CT
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GASES and FUMES can be dangerous.
When welding with electrodes which require special ventilation such as stainless or hard
facing or on lead or cadmium plated steel and other metals or coatings which produce
highly toxic fumes, keep exposure as low as possible and keep the exposure level under
“Minimum Limit Values” using local exhaust or mechanical ventilation. In confined spaces
or in some circumstances, a respirator may be required even outdoors. Additional
precautions are also required when welding on galvanized steel.
Do not weld in locations near chlorinated hydrocarbon vapors coming from degreasing,
cleaning or spraying operations. The heat and rays of the arc can react with solvent
vapors to form a highly toxic gas, and other irritating products.
Welding may cause fumes and gases that are injurious to health. Always enough
ventilation should be used or fumes and gases should be exhausted from breathing
place.
Generally in welding applications; temporary effects for short time can be seen such as
face and skin burning, dizziness, nausea and fever based on exposure period and
amount of fume. Long time fume exposure may cause iron loading and dysfunctions in
lungs. Bronchitis and pulmonary fibrosis are primary effects occurred.
Some electrodes may include alloys that entail special ventilation. Label of these
products that entails special ventilation should not be ignored and  gProduct Safety
Information Form h reports should be read carefully. When welding on this kind of
materials it may be necessary to use gas mask.
Keeping your head out of fume clouds is the easiest way for protection against toxic fumes
and gases.
Avoid breathing these fumes and gases, air circulation or mechanical ventilation
equipments should be used and if the ventilation is not enough gas mask should be used.

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Expressweld MasterMIG 250CT
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WELDING and CUTTING SPARKS can cause fire or
explosion.
Where compressed gases are to be used at the job site, special precautions should be
used to prevent hazardous situations.
Do not heat, cut or weld tanks, drums or containers until the proper steps have been taken
to insure that such procedures will not cause flammable or toxic vapors from substances
inside. Tanks, drums or containers can cause an explosion even though they have been
cleaned. For information, read “Recommended Safe Practices for the Preparation for
Welding and Cutting of Containers and Piping That Have Held Hazardous Substances”,
AWS F4.1 from American Welding Society.
Connect work cable to the piece being welded as close as possible. Work cables
connected to the building framework or other locations away from the welding area
increase the possibility of the welding current passing through lifting chains, crane cables
or other alternate circuits. This can create fire hazards or overheat lifting chains or cables
until they fail.
Keep away fire hazards from welding area and have a fire extinguisher readily available.
Remember that welding sparks and hot materials from welding operation can easily go
through small cracks and openings to adjacent areas. Until ensuring that precautions are
used to fully clean flammable and toxic gases, never weld any tanks, drums, containers or
material. Never operate welder in places that flammable gases, vapors or liquid fuels
exist.
Always keep in mind the fire risk due to high temperatures in arc welding. Welding arc
temperature may increase up to 5000 ‹C, but generally this temperature is not the only
fire reason. Fire risk may be occurred due to sparks or melted metals splashed around.
These metals may splash up to ten meters away. Therefore keep inflammable materials
away from welding area. Also make sure that your work piece do not contact with any
material that may flare when heated. Material, that may flare with contact are divided into
three categories as liquids (fuel, oil, paint, thinner etc.), solids (wood, cartoon, paper etc.)
and gases (acetylene, hydrogen etc.).
Inspect the welding area. If there are systems operating with fuel or hydraulic oil and if you
cannot move welding area or system, place fire-resistant protecting screen between
them.

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Expressweld MasterMIG 250CT
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FIRE DANGER may cause accidents.
If you are working above floor level or on stairway, make sure there is no flammable or
explosive material below. Also please remember that slag and sparks may splash on
people around.
Special precautions should be used when welding in dusty environment. Dust particles
may burn and may cause sudden fire or explosion. If you don't have information about the
inflammableness and fugacity of the dust in the environment, do not start welding or
cutting until it is inspected and approved by expert and authorized person.
Before starting to the welding procedure, please check if there is any flammable or self-
ignition under heat coating on the surface of your work piece.
When you have a break in welding process, please make sure that the electrode holder
do not contact to the ground or work piece.
If you are welding within ten meters to the place where flammable materials located, have
a observor near you. This observer should watch where the sparks and splashes go and
should access easily to the fire extinguishers when necessary. After welding process,
please check if there is any fume around for half an hour with the observer.
As in other emergency situations, first rule is not to panic in situations where welding
accidents happen. According to the size of the fire, to warn the others activate the fire
alarm, inform fire station, shut down the plasma cutting machine and leave the building
from fire exits as soon as possible.
To prevent the risk for every kind of arc glare and fire, never leave the welding torch on
welding desk or any surface in contact with work clamp.
Never refuel near to the welding arc or if there is any engine operating in the surrounding
area. Stop the engine and allow it to cool before refueling to prevent spilled fuel from
vaporizing on contact with hot engine parts and igniting. While refilling the tank, do not
spill fuel around.

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Expressweld MasterMIG 250CT
Use only compressed gas cylinders containing the correct shielding gas for the process
used and properly operating regulators designed for the gas and pressure used. All
hoses, fittings, etc. should be suitable for the welding application and maintained in
good condition with a proper installation.
Always keep cylinders in an upright position securely chained to an undercarriage or
fixed support.
Carefully choose the locations of the cylinders:
Cylinders should be kept away from areas where they may be struck or subjected
to physical damage.
Cylinders should be located to a safe distance from arc welding or cutting
operations and any other source of heat, sparks or flame.
Never allow the electrode, electrode holder or any other electrically “hot” parts to touch
a cylinder.
Keep your head and face away from the cylinder valve outlet when opening the
Valve protection caps should always be in place and hand tight except when the
cylinder is in use or connected for use (including the transportation of the cylinder).
CYLINDER may explode if damaged.
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MOVING PARTS may hurt your hands.
cylinder valve.
Always keep all safety guards, coverings and equipments in place and maintain in good
condition. Always keep your hands, hair, clothing and tools away from V-belt, gears, fans
and all other moving parts when starting, operating or repairing the equipment.
In some cases, it may be necessary to remove safety guards to perform required
maintenance. Remove the guards only when necessary and replace them when the
maintenance requiring their removal is complete. Always use the greatest care when
working near moving parts.
Never put your hands near to the cooling fan while it is operating.
To prevent accidentally starting gasoline engines while turning the engine or welding
generator during maintenance work, disconnect the spark plug wires, distributor cap or
magneto wire as appropriate.

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Expressweld MasterMIG 250CT
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For electrically powered equipment.
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WELDED HOT material may cause burns.
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ELECTRIC and MAGNETIC fields may
be hazardous on human health.
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Compliance with CE NORMS,
SAFETY USAGE.
Turn off input power using the disconnect switch at the fuse box before working on the
equipment. Install equipment in accordance with local codes in force.
GROUNDING: Power cables should be connected to a well grounded plug for your
safety and proper operation of the equipment.
Periodically inspect the conditions of electrode cables, supply cables and cables
connected to the equipment. If you notice any improper situation, immediately replace
damaged parts with the new ones. To prevent the risk for every kind of arc glare and fire,
never leave the electrode holder on welding desk or any surface in contact with work
clamp.
High amounts of heat may be produced from welding process. Hot surfaces and material
may cause serious burns. While touching or moving this kind of material, always wear
gloves.
Electric current flowing through any conductor causes electromagnetic fields. This
electromagnetic field may interfere with devices such as pacemaker. Welders having a
pacemaker shall consult their physician before operating this equipment. Exposure to
electric and magnetic fields may have other health effects which are not known yet (For
detailed information, refer to Page 12).
This machine has been manufactured as per “European Instructions”.
This machine is suitable for welding in environments where there is high electric shock
risk.

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Expressweld MasterMIG 250CT
EXTRA SAFETY MEASURES:
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Semi-automatic DC constant voltage welders,
DC manual arc welders,
AC welders with reduced voltage control.
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PRECAUTIONS FOR OTHERS IN THE WORKING ENVIRONMENT:
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In some situations applying safety measures may be difficult, but even so follow the
mentioned rules. Keep your gloves dry, if getting wet is unavoidable then have an extra
pair of gloves near you. Stand on a plywood, plastic mat or similar dry and insulating
material. Insulate your body from welding piece.
If welding must be performed under electrically hazardous conditions such as in damp
locations or while wearing wet clothing, on metal structures such as floors, gratings or
scaffolds, when in cramped positions such as sitting, kneeling or lying, if there is a high
risk of unavoidable or accidental contact with the workpiece or ground, prefer to use the
following equipment:
Conditions of electrode holder and cables are too important. Plastic or fiber insulating
material on holder prevents contact to electrically hot" places. Before starting the "
welder, always check the condition of the holder. Replace the old and worn ones,
never attempt to repair. Perform same checks for the cables, since the cost will be
high to replace cables, repair by using tubw with high insulation or similar. Always
check the insulations before every time you start the welder.
If you feel an electric shock, always remember that this is a warning. In such case
before continue to work, check your machine, working routines and working
environment against electric shock. If there is an abnormal situation, never continue
welding without using the necessary precaution. If you cannot determine the source of
problem, have an expert and authorized person to check it.
Cleanliness and tidiness of working environment is extremely important for your safety as
well as other people in the environment. While other welders working or people walking
around the welding area may step onto your weld puddle by mistake or may cause you
and others to fall down by tripping over cables and electric shock risk. Also welding
sparks may cause burn danger by splashing on other people around.
Surrounding welding area with fire resistant screens reduces potential risks.
Also warn other people in the working environment for the use of work safety equipments.
Especially when they have to be in welding area, warn them to use fire and flame resistant
work safety clothing, welding goggles, welding mask, insulated work shoes and gloves.

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INFORMATION ON RESIDUAL RISKS:
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Expressweld MasterMIG 250CT
Keep away any people who do not follow the instructions.
When working above floor level, use related warning signs to prevent splashing of melted
metals and welding sparks on people under working area.
Electromagnetic fields may be hazardous for pacemakers.
Make the necessary warnings and use warning signs for other people working or passing
around who are not related to welding work. Inform them that they have to contact with
their doctors before working in a welding environment.
In welding environments there is high electric shock risk. Other people may encounter
electric shock risk by tripping over cables while working. Do not use uninsulated welding
cables, route cables through insulated, plastic channels if available.
Expressweld MasterMIG 250CT welder has been designed and manufactured in
compliance with safety rules required by TS EN 60974-1 standard. To eliminate the safety
risks all necessary precautions have been taken, precautions that need to be taken by
operators and users and all rules to be followed have been stated in the user manual. It is
not possible to eliminate the risks in cases that necessary care is not taken or safety
measures are not used. These risks may cause slight injuries but at the same time fire and
explosion risks may be fatal for more than one people. It is the user's responsibility to
assure the safety of environment where the welding operation is performed, in cases that
precautions are not used or lacking, work must be stopped immediately and authorized
people should be informed.

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Expressweld MasterMIG 250CT
ELECTROMAGNETIC COMPATIBILITY
ELECTROMAGNETIC fields may be hazardous.
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After turning on the power unit, you should wait approximately for 5-10
seconds for electrical stability of the machine and then
start to welding procedure.
Designed according to TS EN 60974-1.
EMU Class of machine according to TS EN 55011 is Group 2 Class A.
For detailed information refer to TS EN 60974-10.
While welding do not turn on/off the power switch.
This situation may cause voltage fluctuations in mains as well as shorten the
economic life of the machine.
Welding machine has been designed according to related norms and rules. In addition, it
may cause safety problem for the devices affected from electromagnetic waves since it
may produce interfering electromagnetic waves for telecommunication devices
(telephone, radio, television) and safety equipments. To prevent and eliminate the effect
of these electromagnetic waves (interferences) produced by the machine, please read
below explanations carefully.
Welding machine has been intended to use in industrial fields. In case of using in living
spaces, to eliminate potential effects of electromagnetic waves it is necessary to use
specific precautions. User should certainly install and operate the machine as per the
instructions included in the user guide. In case any electromagnetic interference is
detected, user should take necessary precautions for this. If necessary, Kaynak Tekniği
Sanayi ve Ticaret A.Ş. will help to the user in this matter. No modifications should be
made on the machine without the written consent of Kaynak Tekniği Sanayi ve Ticaret
A.Ş.
Before the installation of the welding machine, user should check if there is any device in
the working area that may be affected due to electromagnetic waves. Some of these
devices are stated below:
1 - Lead wires, control cables and phone cables near the working area and machine,
2 - Radio and/or television receivers and transmitters, telecommunication devices,
3 - Computers or computer controlled devices,
4 - Safety and control equipments for industrial processes,
5 - Personal medical devices such as pacemakers and hearing aids,
Electromagnetic fields may interfere with some pacemakers. Therefore welders having
pacemakers should contact with their physicians before welding process.
6 - Calibration and measuring devices.

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Expressweld MasterMIG 250CT
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Electromagnetic resistance of the equipments located and working in working area
should be checked. User must be sure that other surrounding devices will operate in
harmony with the machine. To achieve this extra protection measures may be necessary.
To reduce the effect and exposure level of electromagnetic waves produced by the
machine, below warnings should certainly taken into account:
1 - Mains supply connection should be performed as explained in the user manual. If
electromagnetic interference occurs, it may be necessary to take some precautions
like filtering the electric main.
2 - Lead wires (electrode and work cables) should be as short as possible and should be
routed together. Never wrap these cables around your body and stand between the
cables and pay attention that the cables are not on the grounded surfaces.
3 - Work cable should be connected to the piece being welded as close as possible.
4 - While welding operation, keep the power unit in a place as far as possible.
5 - Insulation of cables within the working area may reduce the electromagnetic
interference. This situation may be necessary for some special applications.
6 - To reduce electromagnetic interference and increase work safety, ground the work
piece if possible. User should check if this grounding may cause problem for himself
and for the machine.
7 - Ideal measurements of the working area should be determined based on the
construction of this area and other factors included.
8 - To achieve respectively harmonic current emissions and voltage fluctuations and
flicker limits according to TS EN 61000-3-12 and TS EN 61000-3-11 standards,
recommended mains supply's minimum short circuit power should be 1.0 MVA and
maximum impedance should be 0.41 Ω.

Page 14
2 General Information, Warnings and Operation Conditions
Warning!
Read entire section before installing and starting the machine.
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Expressweld MasterMIG 250CT
Do not install, operate or repair the welder without reading safety precautions included in
user manual. Keep this user manual and place to an easy accessible place.
After completing the work or if you will discontinue working for a long time, disconnect the
mains supply.
Do not insert any object into the welder. While the welder is operating, especially do not
touch to the moving parts with your fingers.
Do not perform any modification on the machine. This may affect the machine features
and cause change in technical values.
It is forbidden to perform any modifications and adaptations on the machine. Performing
any modifications and adaptations, not only cause losing guarantee rights but also may
endanger the usage safety of the machine and may cause electric shock for the users.
Always ground the welder before operating. Various welders or other electrical devices
should be connected in series if they are using the same grounding line, all machines or
devices should be connected in parallel to each other. Cross sectional area of the
grounding cable of the welder should not be less than the cross sectional area of the cable
in the mains input.
While welding, do not change the position of “Welding Voltage Selection Switch”.
Welder should be used in places with good environment lighting and should not be used
in dark places. Also the plasma cutting machine has been designed to be used indoors
and is not suitable for using under sunlight, rain and snow. Welder cannot be used for pipe
melting works.
Welder has been designed to be used indoors and is not suitable for using under sunlight,
rain and snow.
Misuse or welding machine damages due to user mistake voids the guarantee rights.
Do not step on torch cable and do not keep the folding angle of the cable too narrow.
Accepted ambient temperature while operating is between - 10°C and + 40°C.
Accepted ambient temperature while transporting and storing is between - 20℃ and +
55℃.
Allowable relative humidity rate is up to 90% at 20°C and up to 50% at 40°C.

Expressweld MasterMIG 250CT
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Heating tests have been performed in ambient temperature and operation cycle has been
determined with simulation at 40°C.
Operate the machine in a well ventilated environment and leave at least 50 cm free space
around it. Do not operate in places higher than 100 m.
To achieve a stabile arc when operating in a windy place, take precaution against wind.
Wind speed should be less than 1m/sec. If the wind speed is higher than this, use
protective screens.
Manufacturer company reserves its right to change specifications without notice.
For long economical life and safety operation, it is useful to take some simple precautions
stated below:
Do not place the machine on a surface with a slope over 15° and do not operate on such
surface.
Machine should always be operated in an environment having clean airflow and there
should be no obstacle that prevents ventilation or stops airflow. Do not cover the machine
while operating with paper, cloth or similar objects.
While welding, make sure that the cover of the wire drive unit is closed.
Dust and dirt may enter into machine. This should be reduced as much as possible. Do
not operate the machine in extremely dusty locations and environments having water,
paint and oil particles and also grinding dusts and abrasive gases in its atmosphere.
This machine has IP21S protection. Keep the machine dry as much as possible and do
not place it on wet ground or in puddles.
Place the machine far away from radio controlled devices. Normal operation of the
machine may interfere with this kind of devices nearby and in such case may cause injury
or failure of the equipment. Please read “Electromagnetic Compatibility” section included
in this manual.
If the frame cover is opened and interfered by people who are not qualified for electrical
equipments, life-threatening danger may occur. In case behaving on the contrary, be
regarded as accepting beforehand all potential negative consequences.