Arcoweld ArcoMiG LCD 250C User manual

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CONTENT
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CONGRATULATIONS!
THANK YOU FOR YOUR PURCHASE OF THIS
QUALITY ARCOWELD PRODUCT!
WELCOME TO THE ARCOWELD TEAM!
We look forward to supporting you with dependable service and
our extensive range of first-class products.
Our range can be viewed at - https://arcoweld.com.au/
For support please contact your Authorised
distributor or Arcoweld directly
T: + 61 8 9248 3188
F: + 61 8 9248 3166
93 Mulgul Road, MALAGA, WA 6090
PO Box 3087, MALAGA DC, WA 6945
Email- [e-mail]
Website- www.alloysteel.net

CONTENT
III

4
1 SAFETY
1.1 Signal Explanation
The above signals mean warning! Notice! Running parts and electric shocks can injure or kill.
It is a safe operation after taking several necessary protection measures.
1.2 Arc Welding Damage
The following signals and word explanations relay dangers present during the welding operation.
Please be aware and cautious.
Only persons who are trained professionally can install, debug, operate, maintain and repair the
equipment.
During the operation, only required persons shall be present within the welding area. Nil children
should be present.
After shutting off the machine power, please maintain and examine the equipment according to
section 5 because of the DC voltage existing in the electrolytic capacitors.
ELECTRIC SHOCK CAN KILL.
Never touch electrical parts.
Wear dry, hole-free gloves and clothes to insulate yourself.
Insulate yourself from work and ground using dry insulation. Make certain the insulation is large
enough to cover your full area of physical contact with work and ground.
Take care when using the equipment in confined spaces, at heights and in wet environments.
Always shut down the machine power before installation and adjustment.
Ensure to install the equipment correctly and ground the work or metal to be welded to a good
electrical (earth) ground according to the operation manual.
The electrode and work (or ground) circuits are electrically “hot” when the welder is on. Do not touch
these “hot” parts with your bare skin or wet clothing. Wear dry, hole-free gloves to insulate hands.
In semiautomatic or automatic wire welding, the electrode, electrode reel, welding head, nozzle or

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semiautomatic welding 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.
Maintain the electrode holder, work clamp, welding cable and welding machine in good, safe operating
condition. Replace damaged insulation.
Never dip the electrode in water for cooling.
Never simultaneously touch electrically “hot” parts of electrode holders connected to two 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.
FUMES AND GASES CAN BE DANGEROUS.
Welding may produce fumes and gases hazardous to health. Avoid breathing these fumes and gases.
When welding, keep your head out of the fume. Use enough ventilation and/or exhaust at the arc to
keep fumes and gases away from the breathing zone. 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 below Threshold
Limit Values using local exhaust or mechanical ventilation. In confined spaces or in some circumstances
outdoors, a respirator may be required. 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 phosgene, a
highly toxic gas, and other irritating products.
Shielding gases used for arc welding can displace air and cause injury or death. Always use enough
ventilation, especially in confined areas, to ensure breathing air is safe.
Read and understand the manufacturer’s instructions for this equipment and the consumables to be
used, including the material safety data sheet and follow your employer’s safety practices.
ARC RAYS CAN BURN.
Use a shield with the proper filter and cover plates to protect your eyes from sparks and the rays of

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the arc when welding or observing open arc welding.
Use suitable clothing made from durable flame-resistant material to protect your skin and that of your
helpers from the arc rays.
Protect other nearby personnel with suitable, non-flammable screening and /or warn them not to
watch the arc nor expose themselves to the arc rays or to hot spatter or metal.

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SELF-PROTECTION
Keep all equipment safety guards, covers and devices in position and in good repair. Keep hands, hair,
clothing and tools away from V-belts, gears, fans and all other moving parts when starting, operating or
repairing equipment.
Do not put your hands near the engine fan. Do not attempt to override the governor or idler by
pushing on the throttle control rods while the engine is running.
DO NOT add fuel near an open flame welding arc or when the engine is running.
Stop the engine and allow it to cool before refueling to prevent spilled fuel from vaporizing on contact
with hot engine parts and igniting. Do not spill fuel when filling the tank. If fuel is spilled, wipe it up and
do not start engine until fumes have been eliminated.
WELDING SPARKS can cause fire or explosion.
Remove fire hazards from the welding area. If this is not possible, cover them to prevent the welding
sparks from starting a fire. Remember that welding sparks and hot materials from welding can easily go
through small cracks and openings to adjacent areas. Avoid welding near hydraulic lines. Have a fire
extinguisher readily available.
Where compressed gases are to be used at the job site, special precautions should be used to prevent
hazardous situation.
When not welding, make certain no part of the electrode circuit is touching the work or ground.
Accidental contact can cause overheating and create a fire hazard.
Do not heat, cut or weld tanks, drums or containers until the proper steps have been taken to ensure
that such procedures will not cause flammable or toxic vapors from substances inside. They can cause
an explosion even though they have been “cleaned”.
Vent hollow castings or containers before heating, cutting or welding. They may explode.
Sparks and spatter are thrown from the welding arc. Wear oil free protective garments such as leather
gloves, heavy shirt, cuff less trousers, high shoes and a cap over your hair. Wear ear plugs when welding
out of position or in confined places. Always wear safety glasses with side shields when in a welding

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area.
Connect the work cable to the work as close to the welding area as practical. 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.
Rotating parts may be dangerous.
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 application and maintained in good condition.
Always keep cylinders in an upright position securely chained to an undercarriage or fixed support.
Cylinders should be located:
-Away from areas where they may be struck or subjected to physical damage.
-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 cylinder valve.
Valve protection caps should always be in place and hand tight except when the cylinder is in use or
connected for use.
1.3 The knowledge of Electric and Magnetic Fields
Electric current flowing through any conductor causes localized Electric and Magnetic Fields (EMF). The
discuss on the effect of EMF is ongoing all the world. Up to now, no material evidences show that EMF
may have effects on health. However, the research on damage of EMF is still ongoing. Before any
conclusion, we should minimize exposure to EMF as few as possible.
In order to minimize EMF, we should use the following procedures:

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Route the electrode and work cables together – Secure them with tape when possible.
All cables should be put away and far from the operator.
Never coil the power cable around your body.
Make sure welding machine and power cable are as far away from the operator as possible according
to the actual circumstance.
Connect the work cable to the workpiece as close as possible to the area being welded.
Persons with heart-pacemakers should be away from the welding area.

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2 SUMMARY
2.1 Brief Introduction
Arcomig 250C welding machine utilizes the latest pulse width modulation (PWM) technology and
insulated gate bipolar transistor (IGBT) power module, which can replace large transformer type welders.
Inverters are portable, small, lightweight, with low power low consumption. This machine performs four
welding processes, such as MIG, MMA, AC TIG and DC TIG.
Characteristics：
★The ZVS soft switch technology reduces the IGBT switching loss.
★The machine uses Power Factor Correction, which increases the electrical
efficiency of the machine.
★The machine comes complete with protection safeguards such as
overvoltage, over-current, over-heating and so on. Those functions
obviously improve the stability and security of the welding machine.
★The panel combines two kinds of control modes, making it easy for user to
operate.
★MCU control system responds immediately to any changes.
The ArcoMig 250C 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.

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MMA——Manual Metal Arc welding
PWM——Pulse-Width Modulation
IGBT——Insulation Gate Bipolar Transistor
2.2 Module Explanation
Arco - Arcomig
Mig – Metal Inert Gas
250C – Max amperage compact machine
2.3 Working Principle
The working principle of the ArcoMig 250c is shown as the following figure. Single phases work
frequency AC 220V (50 Hz) is rectified into DC (about 380V), then is converted to medium frequency AC
(about 44KHz) by inverter device (IGBT), after reducing voltage by medium transformer (the main
transformer) and rectifying by medium frequency rectifier (fast recovery diode), and is outputted by
inductance filtering. The circuit adopts current feedback control technology to insure current output
stably. Meanwhile, the welding current parameter 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
DC AC DC
AC DC
220V,50HZ
Single-phases AC
2.4 Volt-Ampere Characteristic
ArcoMig 250C welding machine has an excellent volt-ampere characteristic, whose graph is shown
as the following figure. The relation between the conventional rated loading voltage U2and the
conventional welding current I2is as follows:
When I2≤600A，U2=10+0.04I2(V); When I2＞600A, U2=34(V).

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67
34
10
0600 I2（A）
U2（V）
Working
point
Volt-ampere characteristic The relation between the
conventional loading
voltage and welding current

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3 Installation and Adjustment
3.1 Parameters
Model
Parameters
ArcoMig 250C
MIG TIG MMA
Input Voltage（V）1~110±10%
1~220±10%
Input Current（A）
32.6A24.8A31.4A
36.2A 27.0A 40.0A
Efficient Input Current（A）
32.6A24.8A31.4A
22.9A 40% 17.1A 40% 25.3A 40%
18.1A 25% 13.5A 25% 20A 25%
Input Power（KW）
3.6KW 2.7KW 3.4KW
7.7KW 5.9KW 8.6KW
Welding Current（A）
10A~140A 10A~140A 10A~110A 
10A~250A 10A~250A 10A~250A
No-load Voltage（V）45V（adjustable）
Duty cycle
（40℃10min）
140A100%
140A 100%
110A 100%
250A 40%
195A 60%
158A 100%
250A 40%
195A 60%
158A 100%
250A 40%
195A 60%
158A 100%
250A 25%
165A 60%
130A 100%
250A 25%
165A 60%
130A 100%
250A 25%
165A 60%
130A 100%

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Diameter(mm)
Efficiency (%)
80%
85%
82%
85%
82%
85%
Power Factor 0.99
Cooling AF
Protection class IP23
Electrode Diameter
Fe：0.6/0.8/0.9/1.0 Al:0.9/1.0/1.2/1.6
Flux:0.9/1.0/1.2/1.6
Electrode Type
Insulation class F
Dimensions（mm）615×280×480
Weight（Kg）22.0
3.2 Duty cycle & Overheat
The letter “X” stands for duty cycle, which is defined as the proportion of the time that a
machine can work continuously within a certain time (10 minutes).
The rated duty cycle means the proportion of the time that a machine can work continuously

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within 10 minutes when it outputs the rated welding current.
The relation between the duty cycle “X” and the output welding current “I” is shown as the
right figure.
If the welder is over-heat, the IGBT over-heat protection unit inside it will output an instruction
to cut output welding current and brighten the over-heat pilot lamp on the front panel. At this
time, the machine should be relaxed for 15 minutes to cool the fan. When operating the machine
again, the welding output current or the duty cycle should be reduced.
3.3 Movement and placement
Please take care when moving the welder when moving it, and do not sit it on uneven ground.
It also can be moved by the handle on the top of the welder. Place the welder carefully when
moving it to the right position. When the machine gets to the destination, it needs to be secured
to prevent movement.
Movement may result in the potential danger or substantive hazard, so please make sure that the
machine is in a safe position before using it.
3.4 Power supply input connection
ArcoMig 250C welding machines’ power supply connects to 220 V.
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 lifespan. 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;
Reduce the machines workload and ensure input supply is regular.
Set the voltage stabilization device in the front of power cable input.

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3.5 Polarity Connection（MMA）
MMA (DC): Choosing the connection of DCEN or DCEP according to the different electrodes.
Please refer to the electrode manual.
3.6 Assembling the equipment (TIG)
Workpiece is connected to the positive electrode of welding machine, and welding torch is
connected to the negative electrode, which is called DC NEGATIVE CONNECTION; Generally, it
is usually operated in DC NEGATIVE CONNECTION in TIG welding mode.
The control cable of torch switch consists of 2 wires, UP-DOWN control of 3 wires and the

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aero socket has 8 leads.
Consumable parts for TIG torch, such as tungsten electrode、tip、gas nozzle、electrode
shield(short/long) , please contcat Arcoweld or your distributor according to the accessory
codes.
When ArcoMig 250C welding machines are operated in HF ignition method, the ignition spark
can cause interferences in equipment near the welding machine. Be sure to take special
safety precautions or shielding measures.

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4 Operation
4.1 Layout for the panel
ArcoMig 250C
6MIG gun quick connector The MIG welder’s positive polarity output.
7 Positive output The welder’s positive polarity output.
8 Shield gas connector Is connected to the gas input pipe of torch.
9 Aero socket Is connected to torch switch control wire.（It has 14 leads and lead 8 - lead 9
are connected to torch switch control wire）.
10 Negative output The welder’s negative polarity output.
11 Shield gas input joint To connect one head of the gas hose while the other head of which is
connected to argon gas cylinder.
12 Power source switch Switch to “ON”, the welder is turned on, while switch to “OFF”,
the welder is turned off.

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13 Power source input To connect power source.
14 Fan When the electric welding machine is over-heat, the fan operates. It is used for cooling
the components and parts inside the welder.

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4.2 Control panel
Current and wire
feeding speed
adjusting knob
Control knob
LCD Display
Voltage/down
slope/arc force
adjusting knob
Inductance
adjusting knob