-the welding machine does not fall within the requisites of IEC/EN higher current values must be used for flat welding, whereas for
61000-3-12 standard.vertical or overhead welds lower current values are necessary.
Should it be connected to a public mains system, it is the installer's -As well as being determined by the chosen current intensity, the
responsibility to verify that the welding machine itself is suitable for mechanical characteristics of the welded join are also determined
connecting to it (if necessary, consult the distribution network by the other welding parameters i.e. arc length, working rate and
company).position, electrode diameter and quality (to store the electrodes
-Unless otherwise specified (MPG), the welding machines are correctly, keep them in a dry place protected by their packaging or
compatible with power generating sets for voltage oscillations up to containers).
± 15%.
For correct use, the power generating set must be brought to
Procedure
steady conditions before being able to connect the inverter.
-Holding the mask IN FRONT OF THE FACE, strike the electrode tip
on the workpiece as if you were striking a match. This is the correct
-PLUG AND OUTLET:
strike-up method.
-The 230V model is fitted at the factory with a power supply cable
WARNING: do not hit the electrode on the workpiece, this could
and normalised plug, (2P + T) 16A/250V .
damage the electrode and make strike-up difficult.
It can therefore be connected to a mains outlet fitted with fuses or
-As soon as arc is ignited, try to maintain a distance from the
an automatic circuit-breaker; the special earth terminal should
workpiece equal to the diameter of the electrode in use. Keep this
be connected to the earth conductor (yellow-green) of the power
distance as much constant as possible for the duration of the weld.
supply line.
Remember that the angle of the electrode as it advances should be
Table (TAB.1) shows the recommended delayed fuse sizes in
of 20-30 grades (Fig. G).
amps, chosen according to the max. nominal current supplied by
-At the end of the weld bead, bring the end of the electrode
the welding machine, and the nominal voltage of the main power
backward, in order to fill the weld crater, quickly lift the electrode
supply.
from the weld pool to extinguish the arc.
-For welding machines without a plug (115/230V models),
connect a normalised plug (2P + T) - having sufficient capacity-
CHARACTERISTICS OF THE WELD BEAD
to the power cable and prepare a mains outlet fitted with fuses or
Fig. H
an automatic circuit-breaker; the special earth terminal should
7. MAINTENANCE
be connected to the earth conductor (yellow-green) of the power
________________________________________________________________________________
supply line. Table (TAB.1) shows the recommended delayed
fuse sizes in amps, chosen according to the max. nominal
current supplied by the welding machine, and the nominal
WARNING! BEFORE CARRYING OUT MAINTENANCE
voltage of the main power supply.
OPERATIONS MAKE SURE THE WELDING MACHINE IS
________________________________________________________________________________
SWITCHED OFF AND DISCONNECTED FROM THE MAIN POWER
SUPPLY.
WARNING! Failure to observe the above rules will make the
________________________________________________________________________________
(Class 1) safety system installed by the manufacturer ineffective
EXTRAORDINARY MAINTENANCE
with consequent serious risks to persons (e.g. electric shock)
EXTRAORDINARY MAINTENANCE OPERATIONS SHOULD BE
and objects (e.g. fire).
CARRIED OUT ONLY AND EXCLUSIVELY BY SKILLED OR
________________________________________________________________________________
AUTHORISED ELECTRICAL-MECHANICAL TECHNICIANS.
________________________________________________________________________________
CONNECTION OF THE WELDING CABLES
________________________________________________________________________________
WARNING! BEFORE REMOVING THE WELDING MACHINE
PANELS AND WORKING INSIDE THE MACHINE MAKE SURE THE
WARNING! BEFORE MAKING THE FOLLOWING
WELDING MACHINE IS SWITCHED OFF AND DISCONNECTED
CONNECTIONS MAKE SURE THE WELDING MACHINE IS
FROM THE MAIN POWER SUPPLY OUTLET.
________________________________________________________________________________
SWITCHED OFF AND DISCONNECTED FROM THE POWER
SUPPLY OUTLET.
If checks are made inside the welding machine while it is live, this
Table (TAB. 1) gives the recommended values for the welding cables
2
may cause serious electric shock due to direct contact with live
(in mm) depending on the maximum current supplied by the welding
parts and/or injury due to direct contact with moving parts.
machine.
- Inspect the welding machine regularly, with a frequency
________________________________________________________________________________
depending on use and the dustiness of the environment, and
remove the dust deposited on the transformer, reactance and
MMA WELDING
rectifier using a jet of dry compressed air (max. 10bar).
Almost all coated electrodes are connected to the positive pole (+) of
- Do not direct the jet of compressed air on the electronic boards;
the power source; as an exception to the negative pole (-) for acid
these can be cleaned with a very soft brush or suitable solvents.
coated electrodes.
- At the same time make sure the electrical connections are tight
and check the wiring for damage to the insulation.
WELDING OPERATIONS WITH DIRECT CURRENT
- At the end of these operations re-assemble the panels of the
Connecting the electrode-holder clamp welding cable
welding machine and screw the fastening screws right down.
On the end take a special terminal that is used to close the uncovered
- Never, ever carry out welding operations while the welding
part of the electrode.
machine is open.
This cable is connected to the terminal with the symbol (+)
8. TROUBLESHOOTING
Connecting the welding current return cable
IN CASE OF UNSATISFACTORY FUNCTIONING, BEFORE
This is connected to the piece being welded or to the metal bench
SERVICING MACHINE OR REQUESTING ASSISTANCE, CARRY
supporting it, as close as possible to the join being made.
OUT THE FOLLOWING CHECK:
This cable is connected to the terminal with the symbol (-)
-Check that the welding current, which is regulated by the
potentiometer with a graduated amp scale, is correct for the
Warnings:
diamter and electrode type in use.
-Turn the welding cable connectors right down into the quick
-Check that when general switch is ON the relative lamp is ON. If
connections (if present), to ensure a perfect electrical contact;
this is not the case then the problem is located on the mains
otherwise the connectors themselves will overheat, resulting in
(cables, plugs, outlets, fuses, etc.)
their rapid deterioration and loss of efficiency.
-Check that the yellow led (ie. thermal protection interruption-
-The welding cables should be as short as possible.
either over or undervoltage or short circuit) is not lit.
-Do not use metal structures which are not part of the workpiece to
- Check that the nominal intermittance ratio is correct. In case there
substitute the return cable of the welding current: this could
is a thermal protection interruption, wait for the machine to cool
jeopardise safety and result in poor welding.
down, check that the fan is working properly.
-Check the mains voltage: if the value is too high or too low the
6. WELDING: DESCRIPTION OF THE PROCEDURE
welding machine will be stopped.
-It is most important that the user refers to the maker's instructions
- Check that there is no short-circuit at the output of the machine: if
indicated on the stick electrode packaging. This will indicate the
this is the case eliminate the incovenience.
correct polarity of the stick electrode and the most
-Check that all connections of the welding circuit are correct,
suitable current.
particularly that the work clamp is well attached to the workpiece,
-The welding current must be regulated according to the diameter of
with no interferring material or surface-coverings (ie. Paint).
the electrode in use and the type of the joint to be carried out: see
- Protective gas must be of appropriate type (Argon 99,5%) and
below the currents corresponding to various electrode diameters:
quantity.
ø Electrode (mm)Welding current (A)
min.max.
1,625-50
240-80
2,560-110
3,280-160
4120-200
-The user must consider that, according to the electrode diameter,
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