Ronch 250MIG User manual

SERIES
250MIG
MIG

2
CONTENT
1. Safety •4
1.1. Signal Explanation •4
1.2. Arc Welding Damage •4
1.3. The knowledge of Electric and Magnetic Fields •7
2. OVERVIEW •8
2.1. Brief Introduction •8
2.2. Working Principle •9
2.3. Volt-Ampere Characteristic •9
2.4. Principles of Welding •10
3. INSTALLATION & ADJUSTMENT •11
3.1. Parameters •11
3.2. Duty cycle and Over-heat •12
3.3. Equipment Connection •12
3.4. Maintenance of MIG Gun mechanism •13
3.4.1. Dissection graphics for the MIG GUN •13
3.4.2. The parts list for the MIG GUN •14
3.4.3. The operation for the MIG GUN •14
4. OPERATION •16
4.1. Layout for the front and rear panel •17

3
4.2. Welding operation •17
4.2.1. Voltage Setting •17
4.2.2. Wire speed setting •17
4.3. Welding parameters •18
4.4. Operation environment •18
4.5. Operation Notices •19
5. MAINTENANCE & TROUBLESHOOTING •20
5.1. Maintenance •20
5.2. Troubleshooting •21
5.3. Electrical schematic drawing •23

4
1. Safety
•1.1. Signal Explanation
The above signals mean warning! Notice! Running parts and getting an electric shock or thermal
parts will take damage for your body or others. The corresponding notices are as follows. It is
quite a safe operation after taking several necessary protection measures.
•1.2. Arc Welding Damage
The following signals and word explanations are to some damages for your body or others
happening on the welding operation. While seeing these, please remind of yourself or others to
be dangerous.
Only ones who are trained professionally can install, debug, operate, maintain and repair the
equipment.
During the operation, non-concerned people should be lift, especially for children.
After shut off the machine power, please maintain and examine the equipment according to §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 carefully when using the equipment in small place, falling-off and wet circumstance.
Never close 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 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 semiautomatic welding gun are also electrically “hot”.

5
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 the 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.
Shielded gases used for arc welding can displace air and cause injury or death. Always use
enough ventilation, especially in confined areas, to insure 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 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.

6
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 adds the 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 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
insure 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 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.

7
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 discussion 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:
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 to be far away from the operator as far as possible
according to the actual circumstance.
Connect the work cable to the workpiece as close as possible to the area being welded.
The people with heart-pacemaker should be away from the welding area.

8
2. OVERVIEW
•2.1. Brief Introduction
RONCHWELD 250MIG arc welding machine adopts the latest pulse width modulation (PWM)
technology and insulated gate bipolar transistor (IGBT) power module, which can change work
frequency to medium frequency so as to replace the traditional hulking work frequency
transformer with the cabinet medium frequency transformer. Thus, it is characterized with
portable, small size, light weight, low consumption and etc.
RONCHWELD 250MIG arc welding machine uses Mix gas as shielded gas to realize gas shielded
welding, active gas（Ar+O2、Ar+CO2）as shielded gas to realize MAG welding and inactive gas（
Ar）as shielded gas to realize MIG welding.
RONCHWELD 250MIG arc welding machine has automatic protection functions with intelligent to
over-voltage, over-current and over-heat. If any one of the above problems happens, the alarm
lamp on the front panel will be lighted and output current will be shut off automatically to protect
itself and prolong the equipment using life.
RONCHWELD 250MIG Features:
Digital control system, real-time display the welding parameters;
High performance multifunction power source (MIG/MAG);
Waveform control, stable welding arc;
IGBT technology, low power dissipation;
Rated duty circle：RONCHWELD 250MIG is 60%(40℃)
RONCHWELD 250MIG arc welding machine is suitable for all positions welding for various plates
made of stainless steel, carbon steel, alloyed steel etc, which is also applied to pipe installment,
mould mend, petrochemical, architecture decoration, car repair, bicycle, handicraft and common
manufacture.
MAG--Metal Active Gas Welding
MIG--Metal Insert Gas Welding

9
•2.2. Working Principle
The working principle of RONCHWELD 250MIG arc welding machine is shown as the following
figure. Single-phase 220V work frequency AC is rectified into DC（312V）, then is converted to
medium frequency AC (about 40KHz) by inverter device (IGBT), after reducing voltage by medium
transformer (the main transformer) and rectifying by medium frequency rectifier (fast recovery
diodes), and is outputted by inductance filtering when MIG. Meanwhile, the welding current
parameter can be adjusted continuously and infinitely to meet with the requirements of welding
craft.
•2.3. Volt-Ampere Characteristic
RONCHWELD 250MIG welding machine has an excellent volt-ampere characteristic, whose graph
is shown as the following figure. The relation between the rated loading voltage U2and welding
current I2is as follows: U2=14+0.05I2(V)
44
14
0600 Io（A）
Uo（V）
Working point
Volt-ampere characteristic The relation between the rated loading
voltage and welding current
Single-phase AC
220V, 50/60HZ

10
•2.4. Principles of welding

11
3. INSTALLATION & ADJUSTMENT
•3.1. Parameters
Model
Parameters
RONCHWELD 250MIG
Input Voltage（V）
1~220/230/240±10%
Input Current（A）
50
Input Power（KW）
7.3
Welding Current（A）
50-250
Welding Voltage（V）
13.5-26.5
No-load Voltage（V）
47
Duty cycle（40℃）
60% 250A
100% 200A
Diameter(mm)
Fe：0.6、0.8、0.9、1.0 、1.2
Ss：0.8、0.9、1.0、1.2
Flux-cored：0.6、0.8、0.9、1.0 、1.2
Power Factor
0.7
Efficient %
85
Protection class
IP23
Insulation class
H
Cooling
AF
Dimensions（mm）
618*240*445
Weight（Kg）
23
Note: The above parameters are subject to change with the improvement of machines.

12
•3.2. Duty cycle and Over-heat
The letter “X” stands for the 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 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 transformer is over-heat, the heat relay inside it will open
and will output an instruction to circuit board, cut AC relay
and the output welding current, and brighten the over-heat
pilot lamp in 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. Equipment Connection
200
Relation of welding current and duty
cycle for RONCHWELD 250MIG

13
Operation Steps:
Connect the power source input cable of welding machine with the output port of air switch in
electric box on the spot.
Connect the negative pole of welding machine to the work piece (base metal).
Connect the output pipe of gas cylinder to the input joint of gas valve on the welding machine
and clamp it.
Insert the torch joint into the output of welding machine unit and keep the wire aim at the
wire feeder mouth.
Note: The plane of the joint should be aimed at screw, plugged tightly and rotated 90º, then
screw the bolt tightly to ensure the gun contacting closely.
Notice that the wire diameter should be accordant with the wire wheel and torch tip and press the
wire properly with the handle.
•3.4. Maintenance of MIG Gun mechanism
•3.4.1. Dissection graphics for the MIG GUN
标准化
工艺
批准
日期
设计
制图
校对
审合
处数
标记 更改文件号 重量(g)
共页共
日期
签字
上海亿诺科技有限公司
零部件描述 参考编号 材料
公差选择范围
页
外形尺寸
ICT2098
描 述
图 号
序号 备 注
焊枪15/3米/弹性针/蓝色手柄 -------
上海市顾戴路2535弄99号3号楼2楼
16
图 号
序号
1
2
9
3
6
7
8
11
10
12
13
描 述 数量 备 注
12
34
7
11
1213
14
15
1617
ICS0063
ICU0003-08
ICZ6087
ICV0685
IHQ0070
IFT0874
IHJ0715
IHJ0782
14
IHJ0028
IHJ0645
IFT0063
IZT0071
1
1
1
1
3
1
1
1
1
1
1
1
18
17 送丝管锁紧螺母
带绝缘层送丝管0.6-0.8 3米 蓝色IIC0500
导电嘴 0.8/M6*25
喷嘴 D.12 14-15AK
螺丝 M4X6 UNI 6107
15AK 枪颈(包括六角适配器和塑料适配器)
MIG蓝色手柄
焊枪用开关 21.8mm
螺丝 D.3x10
电缆护套 12-16-25 MMQ
电缆支撑用球节 15AK
手柄锁紧环
二氧化碳欧式后把套
数量
1
1
19
18
10
95 6
8
塑料适配器
六角适配器
IZH0667
IHJ0030
5
4
1
15
ITB0059 欧式中央插头/弹性针 1
ICG6000
19 导电嘴扳手 1
IHJ0063 焊枪锁紧螺母/塑料螺纹 1
ICN0663 同轴电缆组/16mmq/3米 1
3.1 ICZ0087 15AK 枪颈 1
3.1

14
•3.4.2. The parts list for the MIG GUN
NO.
Description
QTY.
Remark
1
Tip D.12 14-15AK
1
2
Electric nozzle 0.8/M6*25
1
3
15AK Goose gun neck (Hexangular adapter and Plastic adapter)
1
3.1
15AK Goose gun
1
4
Hexangular adapter
1
5
Plastic adapter
1
6
MIG blue handle
1
7
Torch Switch 21.8mm
1
8
Screw D.3*10
3
9
Handle locking ring
1
10
Cable fixing joint 15AK
1
11
Coaxial cable team /16mmq/3m
1
12
Cable thimble 12-16-25 MMQ
1
13
CO2Euro-rear thimble
1
14
Screw M4*6 UNI 6107
1
15
Torch locknut /plastic screw thread
1
16
Euro-main socket/flexibility pin
1
17
Feeding pipe locknut
1
18
Insulating feed pipe 0.6-0.8 3m, Blue
1
19
Spanner for the electric nozzle
1
•3.4.3. The operation for the MIG GUN
1. Service the wire feed mechanism at least every time the reel is changed.
-Check the wear of the feed roll groove and change the feed roll when necessary.
-Clean the welding gun wire guide with compressed air.
2. Cleaning the wire guide
Pressure of the feed rolls remove metal dust from the filler wire’s surface which then finds its way
to the wire guide. If the wire guide is not cleaned, it gradually clogs up and causes wire feed
malfunctions. Clean the wire guide in the following manner:
Remove the welding gun’s gas nozzle, contact tip and contact tip’s adapter.
With a pneumatic pistol, below compressed air through the wire guide.
Blow the wire feed mechanism and reel housing clean with compressed air.
Reattach the welding gun’s parts. Tighten the contact tip and contact tip’s adapter to spanner
tightness.
3. Changing the wire guide

15
If the wire guide is too worn or totally clogged, change it to a new one according to the following
instructions.
Open the mounting nut of the wire guide which exposes the end of the wire guide.
Straighten the welding gun’s cable and withdraw the wire guide from the gun.
Push a new wire guide in to the gun. Make sure that the wire guide enters all the way into the
contact tip’s adapter and that there is an O-ring at the machine-end of the guide.
Tighten the wire guide in place with the mounting nut.
Cut the wire guide 2mm from the mounting nut and file the sharp edges of the cut round.
Reattach the gun in place and tighten the parts to spanner tightness.
Threading the filler wire
Threading the filler wire as the follow steps:
-Open the reel housing by pressing on the opening button and install the wire reel in such a
way that it rotates counter clockwise. You can use either a diameter 200mm or 100mm
wire reel in the machine.
-Attach the reel with a reel lock.
-Unfasten the wire end from the reel, but hold on it all the time.
-Straighten the wire end for approximately 20 cm and cut the wire in the straightened
location.
-Open the pressure control level which then opens the feed gear.
-Thread the wire through the wire’s rear guide to the gun’s wire guide.
-Close the feed gear and fasten it with the pressure control lever. Make sure that the wire
runs in the feed roll groove.
-Adjust the compression pressure with the pressure control lever no higher than to the
middle of the scale. If the pressure is too high, it removes metal fragments from the wire
surface and may damage the wire. On the other hand, if the pressure is too low, the feed
gear slips and the wire does not run smoothly.
-Press the welding gun trigger and wait for the wire to come out.
-Close the reel housing cover.
Note: When driving the wire into the gun, do not point the gun at yourself or others.

16
4. OPERATION

17
•4.1. Layout for the front and rear panel
1. Welding volt knob: Set the welding volt
2. Voltage display: Welding voltage display when machine is working, Set voltage display when
MIG mode before welding. Unit：V.
3. .Welding current knob: Set the welding current.
4. Current display: Welding Current display when machine is working, Set current display before
welding. Unit：A.
5. Wire speed LED：You can use current setting knob to set the wire speed when the wire speed
LED is on.
6. Current LED：When the current LED is on, it display the actual output welding current.
7. Power Led: Power led is lighted when open the machine.
8. Alarm Led: When the welder is over voltage, less voltage, over current or over heated, the
alarm pilot lamp will be on.
9. Wave control knob: Controls arc characteristics, Determines the rate at which the amperage
rises when a short circuit is produced.
10. Manual wire switch & air check switch: up for manual wire and down for air check.
11. MIG GUN Connect.
12. Output cathode：This polarity must connect the work piece
•4.2. Welding operation
For example RONCHWELD 250MIG
•4.2.1. Voltage Setting
You can use the voltage setting knob to set the output voltage before welding.
•4.2.2. Wire speed setting
You can use current setting knob to set the wire speed when the wire speed LED is on. When the
current LED is on, it display the actual output welding current.

18
•4.3. Welding parameters
Welding current（A）
Welding volt（V）
Wave control
Wire speed
φ0.8
φ1.0
φ1.2
60A
16～17V
0-2
3--4
80A
17～18V
0-2
4--5
3--4
100A
17～19V
2-3
5--6
3--5
2--3
120A
17～19V
2-3
6--7
4--5
3--4
150A
18～20V
3-5
7--9
4--6
4--5
180A
20～23V
3-6
8-10
6--8
5--6
220A
21～24V
4-6
7--10
6--8
250A
22～26V
6-8
7-9
•4.4. Operation environment
Height above sea level ≤1000 M
Operation temperature range -10～+40℃.
Air relative humidity is below 90 %( 20℃).
Preferable site the machine some angles above the floor level, the maximum angle does
not exceed 15℃.
Protect the machine against heavy rain or in hot circumstance against direct sunshine.
The content of dust, acid, corrosive gas in the surrounding air or substance can not exceed
normal standard.
Take care that there is sufficient ventilation during welding. There is at least 30cm free
distance between the machine and wall.

19
•4.5. Operation Notices
Read §1 carefully before attempting to use this equipment.
Connect the ground wire with the machine directly and refer to §3.5.
Ensure that the input is single-phase: 50/60Hz, 220V±10%.
Before operation, no concerned people should be left. Do not watch the arc in
unprotected eyes.
Ensure good ventilation of the machine to improve duty ratio.
Turn off the engine when the operation finished for economize energy sources.
When power switch shuts off protectively because of failure. Don’t restart it until problem
is resolved. Otherwise, the range of problem will be extended.
In case of problems, contact your local dealer if not our authorized maintenance man.

20
5. MAINTENANCE & TROUBLESHOOTING
•5.1. Maintenance
In order to guarantee that arc welding machine works high-efficiently and in safety, it must be
maintained regularly. Let customers understand the maintenance methods and means of arc
welding machine more, enable customers to carry on simple examination and safeguarding by
oneself, try one's best to reduce the fault rate and repair times of arc welding machine, so as to
lengthen service life of arc welding machine .Maintenance items in detail are in the following
table.
● Warning: For safety while maintaining the machine, please shut off the supply power and wait
for 5 minutes, until capacity voltage already drop to safe voltage 36V.
Date
Maintenance items
Daily
examination
Observe that whether panel knob and switch in the front and at the back of arc
welding machine are flexible and put correctly in place. If the knob has not been put
correctly in place, please correct; If you can't correct or fix the knob , please replace
immediately;
If the switch is not flexible or it can't be put correctly in place, please replace
immediately; Please get in touch with maintenance service department if there are
no accessories.
After turn-on power, watch/listen to that whether the arc welding machine has
shaking, whistle calling or peculiar smell. If there is one of the above problems, find
out the reason to get rid of; if you can't find out the reason, Please contact local this
area agent or the branch company.
Observe that whether the display value of LED is intact. If the display number is not
intact, please replace the damaged LED. If it still doesn’t work, please maintain or
replace the display PCB.
Observe that whether the min/max value on LED accords with the set value. If there
is any difference and it has affected the normal welding craft, please adjust it.
Check up that Whether fan is damaged and is normal to rotate or control. If the fan is
damaged, please change immediately. If the fan does not rotate after the arc welding
machine is overheated, observe that whether there is something blocked in the
blade, if it is blocked, please get rid of; If the fan does not rotate after getting rid of
the above problems, you can poke the blade by the rotation direction of fan. If the
fan rotates normally, the start capacity should be replaced; If not, change the fan.
Observe that whether the fast connector is loose or overheated. If the arc welding
machine has the above problems, it should be fastened or changed.