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DESCRIPTION OF THE WELDING MACHINE
The welding machine is a high-frequency current transformer for ma-
nual arc welding, using MMA.
This welding machine has been developed by the use of the electronic
INVERTER technology.
The machine delivers a constant current.
The electrical characteristic of the transformer is that it lowers the
voltage.
This manual refers to a range of welding machines that differ in some
of their characteristics.
Identify your model in Fig. 1.
Main parts Fig. 1
A) Power cable
B) ON/OFF switch
C) Indicator light on.
D) Welding current adjustment
E) Thermal cooling pause indicator light.
F) Display
G) Couplings for welding cables
Technical data
A data plate is affixed to the welding machine. Fig. 2 shows an exam-
ple of this plate
A) Manufacturer name and address.
B) European standard reference for the construction and safety of
the welding equipment.
C) Symbol of the welding machine internal structure.
D) Symbol of the foreseen welding process: D1: MMA welding.
E) Symbol of the continuous current delivered.
F) Input power required:
1" alternate single-phase voltage, frequency: F1: from electrical
power supply; F2: from motor generator.
G) Level of protection from solids and liquids.
H) A symbol indicating the possibility of using the welding machine in
environments potentially subjected to electric discharges.
I) Welding circuit performance.
UoV Minimum and maximum open circuit voltage (open welding
circuit)
I2, U2 Current and delivered corresponding normalized voltage dis-
tributed around the welding machine.
X Duty cycle. Indicates how long the welding machine can work for,
and how long it must rest in order to cool down.
The time is expressed in % on the basis of a 10-minute cycle (e.g.
60% means 6 min. work and 4 min. rest)
A/V Current adjustment area and corresponding arc voltage.
J) Power supply data.
U1 Input voltage (allowed tolerance: +/- 10%)
I1 eff Effective absorbed current.
I1 max Maximum absorbed current.
K) Serial number.
L) Weight.
M) Safety symbols: Refer to Safety Warnings.
STARTING UP
- The installation of the necessary electrical mains supply
must be done according to national and international legal
conformities.
- Connections to the mains must be made by an expert or a qualified
person.
- Before to start make sure that electrical supply installation is made
according to points 1 and 2 and is in perfect state.
- Make sure the welding machine is switched off and the plug is not
connected to the power socket before carrying out this procedure.
- The device must be only connected to a supply system, with an
earthed 'neutral' lead.
- Always visually check or make check by a qualified technician that
as minimum machine has earth connection is connected through a
differential switch (30 mA 30ms trip) and a magneto thermal switch
with class C tripping and a minimum recommended amperage of 32
amperes. If, for example, you connect to a minor amperage (say 10
amperes, for example) switch they can trip if the adjust of power is
high. This is not a machine's problem is a not correct capacity of the
electrical installation for the welding machine.
- Avoid, if possible, extension cords. If you must please use it as short
as possible and as high conductor area as possible. For avoiding
extra loses don't roll the extension cord in your axle. Minimum
section allowable is 2.5mm2, recommended is 4mm2. Don't use
cheap 1.5mm2 extension cords !!.
ASSEMBLY AND ELECTRICAL
CONNECTIONS
Check that the electrical supply delivers the corresponding voltage
and frequency to the welding machine, and make sure it is fitted
with a delayed fuse suited to the maximum delivered rated current
(I2max). Fig. 3,1.
The requirements set out in the IEC/EN61000-3-12 standard, do not
apply to this equipment. If this equipment is connected to a low vol-
tage power supply network, either the installer or the user are res-
ponsible for checking that this can be done (consult the distribution
system operator if required).
In order to comply with the requirements, set out in the EN61000-3-
11 (Flicker) standard, it is recommended to connect the welder to the
supply network interface points, having a lower impedance than the
reference Zmax = Fig. 3,4.
To comply with the requirements of the EN61000-3-12 standard, the
welding machine must be connected to the interface points of the
power supply network that present a short-circuit power equal to or
greater than 8062 kW.
Plug. If the welding machine is not fitted with a plug, fit a normalized
plug (2P+T for 1Ph) of a suitable capacity for the power cable Fig.
3,2.
CONNECTION TO MOTOR GENERATORS
Some welding machines may be powered by a motor generator.
Make sure this has a power of at least 6 kVA, and does not deliver
voltage higher than 270V.
PREPARING THE WELDING CIRCUIT MMA
Connect the ground lead to the welding machine and the piece to be
welded, as close as possible to the point to be welded.
Connect the cable with the electrode holder gripper to the welding
machine, and mount the electrode on the gripper.
In welding machines that deliver direct current, most of the electrodes
are connected to the positive attachment.
Refer to the electrode manufacturer's instructions, concerning the
connection and the welding current.
WELDING PROCESS: DESCRIPTION OF
CONTROLS AND SIGNALS
Once you have put the welding machine into operation,
switch it on and apply the required adjustments.
Adjusting the welding current
Select the welding current depending on the electrode type, joint and
welding position.
Indicatively, the different currents to be used with the different
electrode diameters, are listed in Fig. 4.
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