Sweiss SKYARC 2750 User manual

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Inverter DC MMA Arc Welding Machine
IMPORTANT: Read
this Owner’s Manual Completely before attempting to use this
equipment. Save this manual and keep it handy for quick reference. Pay particular
attention to the safety instructions we have provided for your protection. Contact your
distributor if you do not fully understand this manual.
OPERATORS’ MANUAL
SKYARC 2750

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CONTENT
II
§1 SAFETY ........................................................................................................................................... 1
§1.1 SIGNAL EXPLANATION................................................................................................................................................1
§1.2 ARC WELDING DAMAGE .............................................................................................................................................1
§1.3 THE KNOWLEDGE OF ELECTRIC AND MAGNETIC FIELDS............................................................................................4
§2 SUMMARY ...................................................................................................................................... 5
§2.1 BRIEF INTRODUCTION .................................................................................................................................................5
§2.2 MODEL EXPLANATION.................................................................................................................................................5
§2.3 WORKING PRINCIPLE..................................................................................................................................................6
§2.4 VOLT-AMPERE CHARACTERISTIC ................................................................................................................................6
§3 INSTALLATION & ADJUSTMENT.................................................................................................... 7
§3.1 PARAMETERS ...............................................................................................................................................................7
§3.2 DUTY CYCLE &OVER HEAT .........................................................................................................................................8
§3.3 MOVEMENT AND PLACEMENT ....................................................................................................................................9
§3.4 WELDING POLARITY CONNECTION WAY...................................................................................................................10
§3.5 CONNECTION TO THE MAINS SUPPLY .......................................................................................................................10
§4 OPERATION CONTROL AND CONNECTORS ...............................................................................12
§4.1 LAYOUT FOR FRONT &REAR PANEL..........................................................................................................................12
§4.2 WELDING CURRENT ADJUSTMENT ...........................................................................................................................12
§4.3 ARC FORCE ADJUSTMENT.........................................................................................................................................12
§4.4 HOT START ADJUSTMENT .........................................................................................................................................14
§4.5 WELDING OPERATION..............................................................................................................................................14
§4.5.1 Striking arc way...........................................................................................................................................14
§4.5.2 Manipulation of electrode ........................................................................................................................15
§4.6 WELDING PARAMETERS............................................................................................................................................15
§4.6.1 Joint form in MMA....................................................................................................................................... 15
§4.6.2 Electrode selection...................................................................................................................................... 16
§4.7 ARC WELDING DEFECT AND PREVENT METHOD ....................................................................................................17
§4.8 OPERATION ENVIRONMENT .....................................................................................................................................18
§4.9 OPERATION NOTICES ...............................................................................................................................................18
§5 MAINTENANCE & TROUBLESHOOTING .....................................................................................20
§5.1 MAINTENANCE.........................................................................................................................................................20
§5.2 TROUBLESHOOTING .................................................................................................................................................21
§5.3 ELECTRICAL PRINCIPLE DRAWING ............................................................................................................................24

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SAFETY
1
§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 o 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-o 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 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 semiautomatic welding gun are also electrically “hot”.

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SAFETY
2
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 oor 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 conned 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 conned 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 lter 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 ame-resistant material to protect your skin and
that of your helpers from the arc rays.
Protect other nearby personnel with suitable, non-ammable 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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SAFETY
3
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 ame 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 lling
tank. If fuel is spilled, wipe it up and do not start engine until fumes have been eliminated.
WELDING SPARKS can cause re or explosion.
Remove re hazards from the welding area. If this is not possible, cover them to prevent the
welding sparks from starting a re. 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 re 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 re 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 ammable 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, cu less trousers, high shoes and a cap over your hair. Wear ear
plugs when welding out of position or in conned 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 re hazards or overheat lifting chains or cables until they fail.

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SAFETY
4
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, ttings,
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 xed
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 ame.
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 owing through any conductor causes localized Electric and Magnetic
Fields (EMF). The discuss on the eect of EMF is ongoing all the world. Up to now, no material
evidences show that EMF may have eects 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 arc.

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SUMMARY
5
§2 Summary
This operation manual is suitable for the models of SKYARC 2750
§2.1 Brief Introduction
SKYARC - serires（discrete）welder is a MMA arc welder which adopts the latest pulse
width modulation (PWM) technology and the insulated gate bipolar transistor (IGBT) power
module. It 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.
SKYARC - serires（discrete）has excellent performance: constant current output makes
welding arc more stable; fast dynamic response speed reduces the impact from the arc length
uctuation to the current; accurate stepless current adjustment and pre-setting function. There
are also some automatic protection functions for under voltage, over current, over heat, etc.
inside the welders, when the problems listed before occurred, the alarm on the front panel is
light and at the same time the output current will be cut o. It can self-protect and prolong the
using life and greatly improved the reliability and practicability of the welders.
For SKYARC - serires（discrete）, welding current, arc force and hot start can be adjusted by
the adjustment knob, which can satisfy with several kinds of welding technologies. They can
also realize high quality welding especially for using basic electrode, acid electrode and
cellulose electrode. When using cellulose electrode, they can also realize downward welding
for butt joint in all position.
SKYARC - serires （discrete ）is widely used in Petroleum, chemical, mechanical,
shipbuilding, architecture, boiler, pressure container, war industry and installation and so on.
MMA——Manual Metal Arc welding;
PWM——Pulse-Width Modulation;
IGBT——Insulation Gate Bipolar Transistor
§2.2 Model explanation
The model explanation of arc welding machine accords with the correlative prescripts of
National Standard GB10249, and is as follows.(Take SKYARC as an example)

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SUMMARY
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§2.3 Working Principle
The working principle of SKYARC - serires（discrete）welder is shown as the following gure.
Three-phase 380V work frequency AC is rectied into DC (about 530V), 3-phase 220V work
frequency AC is rectied into DC (about 310V), then is converted to medium frequency AC
(about 20KHz) by inverter device (IGBT module), after reducing voltage by medium transformer
(the main transformer) and rectified by medium frequency rectier (fast recovery diodes), and
is outputted by inductance ltering. 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.
Note: Please refer to the nameplate about the right power supply connection (three
phase 220v or three phase 380v ) .Wrong power connection may cause machine
failure!
Rectify Inverter
Medium
frequency
transformer
Medium
frequency
rectify
Hall device
Current positive-
feedback control
Three-phase,
AC DC AC DC
380V, 50Hz
(220V,50Hz)
AC DC
§2.4 Volt-Ampere Characteristic
SKYARC - serires（discrete）welder has excellent volt-ampere characteristic, seeing the
following graph(Take SKYARC as an example). In MMA welding, the relation between the rated
loading voltage U2and welding current I2 is as follows:
When I2≤600A，U2＝20＋0.04 I2（V）；When I2＞600A，U2＝44（V）.
50
44
20
0600I
2
（A）
U
2
（V）
Working
point
Volt-ampere characteristic
The relation of the rated loading
voltage&welding current

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SUMMARY
2

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INSTALLATION AND ADJUSTMENT
7
§3 Installation & Adjustment
§3.1 Parameters
Model
Parameters
SKY
ARC
27
50
Power source Three-phase，380V±10%，50Hz Three-phase，220V±10%，50Hz
Rated input current（A）13.9 24.2
Rated input power（KW））8.2 8.8
Power factor 0.95 0.93
Welding current range（A）
10~275
Max no load voltage (V) 50
Eciency 91％85%
Duty cycle（40
℃
,10mins）
275A 50%
200A60%
160A100%
Protection class IP23
Insulation class
F
Dimensions of Machine
（
L×W×H
）（
mm
）
410×170×270
Weight（Kg）11.5
Note:
1. The above parameters are subject to change with the improvement of machines.
2. You need to wait for ve seconds to turn on the machine after you turn o the machine，or else
you can not switch on the power source.