Telwin LINEAR 340 Mode D'emploi page 4

of the symbols and numbers; the exact values of technical data for the
welding machine in your possession must be checked directly on the
data plate of the welding machine itself.
OTHER TECHNICAL DATA
- WELDING MACHINE: see table (TAB.1)
- ELECTRODE HOLDER CLAMP: see table (TAB. 2)
4. DESCRIPTION OF THE WELDING MACHINE
Control, regulation and connection devices
5. INSTALLATION
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WARNING! CARRY OUT ALL INSTALLATION OPERATIONS
AND ELECTRICAL CONNECTIONS WITH THE WELDING
MACHINE COMPLETELY SWITCHED OFF AND DISCONNECTED
FROM THE POWER SUPPLY OUTLET.
THE ELECTRICAL CONNECTIONS MUST BE MADE ONLY AND
EXCLUSIVELY BY AUTHORISED OR QUALIFIED PERSONNEL.
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PREPARATION
Unpack the welding machine, assemble the separate parts contained
in the package.
Assembling the return cable-clamp
Assembling the welding cable-electrode holder clamp
HOW TO LIFT THE WELDING MACHINE
The welding machine MUST be lifted as shown in Fig. F.
For all other welding machines never use the handle for lifting.
This holds for the first time the welding machine is installed and
throughout its entire working life.
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WARNING! Position the welding machine on a flat surface
with sufficient carrying capacity for its weight, to prevent it from
tipping or moving hazardously.
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CONNECTION TO THE MAIN POWER SUPPLY
- Before making any electrical connection, make sure the rating data
of the welding machine correspond to the mains voltage and
frequency available at the place of installation.
- The welding machine should only be connected to a power supply
system with the neutral conductor connected to earth.
PLUG AND OUTLET
Connect a normalised plug (3P + T) having sufficient capacity- to the
power cable and prepare a mains outlet fitted with fuses or an
automatic circuit-breaker; the special earth terminal should 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 voltage of the main power supply.
Set the locking screw on the knob of the voltage change switch to the
position corresponding to the actual available main power supply
voltage.
The model with I ³ 450A has an internal voltage change switch, which
2
can be reached by removing the right panel (FIG. G1).
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WARNING! Failure to observe the above rules will make the
(Class 1) safety system installed by the manufacturer ineffective
with consequent serious risks to persons (e.g. electric shock)
and objects (e.g. fire).
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CONNECTION OF THE WELDING CABLES
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WARNING! BEFORE
CONNECTIONS MAKE SURE THE WELDING MACHINE IS
SWITCHED OFF AND DISCONNECTED FROM THE POWER
SUPPLY OUTLET.
Table (TAB. 1) gives the recommended values for the welding cables
2
(in mm ) depending on the maximum current supplied by the welding
machine.
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WELDING OPERATIONS WITH DIRECT CURRENT
Connecting the electrode-holder clamp welding cable
On the end take a special terminal that is used to close the uncovered
part of the electrode.
This cable is connected to the terminal with the symbol (+).
Connecting the welding current return cable
This is connected to the piece being welded or to the metal bench
supporting it, as close as possible to the join being made.
This cable is connected to the terminal with the symbol (-).
Fig. B
Fig. C
Fig. D
Fig. E
FIG. G
MAKING THE FOLLOWING
Warnings:
- Turn the welding cable connectors right down into the quick
connections (if present), to ensure a perfect electrical contact;
otherwise the connectors themselves will overheat, resulting in
their rapid deterioration and loss of efficiency.
- The welding cables should be as short as possible.
- Do not use metal structures which are not part of the workpiece to
substitute the return cable of the welding current: this could
jeopardise safety and result in poor welding.
6. WELDING: DESCRIPTION OF THE PROCEDURE
These welding machines are direct current power sources, suitable for
arc welding using electrodes with a range of coatings (rutile, acid,
basic).
To switch on the welding machine turn the main switch (FIG. B (3)).
The output welding current intensity can be adjusted continuously,
using a manually operated magnetic shunt (FIG. B (1)).
The value of the current setting (I ) can be read on the graduated scale
in Amps (FIG. B (4)) on the front panel.
The current shown corresponds to the arc voltage (U ) according to
the following relationship:
U = (20 + 0,04 I ) V (EN 60974).
2 2
WELDING
- Almost all stick electrodes are to be connected to the positive pole
(+) of the power source, only exceptionally to the negative pole (-)
(acid covering).
- It is most important that the user refers to the maker's instructions
indicated on the stick electrode packaging. This will indicate the
correct polarity of the stick electrode and the most suitable current.
- The welding current must be regulated according to the diameter of
the electrode in use and the type of the joint to be carried out: see
below the currents corresponding to various electrode diameters:
ø Electrode (mm)
1.6
2
2.5
3.2
4
5
6
8
- The user must consider that, according to the electrode diameter,
higher current values must be used for flat welding, whereas for
vertical or overhead welds lower current values are necessary.
- In addition to being determined by the selected current intensity, the
mechanical characteristics of the welded join are determined by the
other welding parameters i.e. arc length, working rate and position,
electrode diameter and quality (to store the electrodes correctly
keep them dry and protected by suitable packaging or containers).
Welding procedure
- 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
strike-up method.
WARNING: do not hit the electrode on the workpiece, this could
damage the electrode and make strike-up difficult.
- As soon as arc is ignited, try to maintain a distance from the
workpiece equal to the diameter of the electrode in use. Keep this
distance as much constant as possible for the duration of the weld.
Remember that the angle of the electrode as it advances should be
of 20-30 grades
(Fig. H).
- At the end of the weld bead, bring the end of the electrode
backward, in order to fill the weld crater, quickly lift the electrode
from the weld pool to extinguish the arc.
CHARACTERISTICS OF THE WELD BEAD
7. MAINTENANCE
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WARNING! BEFORE CARRYING OUT MAINTENANCE
OPERATIONS MAKE SURE THE WELDING MACHINE IS
SWITCHED OFF AND DISCONNECTED FROM THE MAIN POWER
SUPPLY.
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EXTRAORDINARY MAINTENANCE
EXTRAORDINARY MAINTENANCE OPERATIONS SHOULD BE
CARRIED OUT ONLY AND EXCLUSIVELY BY SKILLED OR
AUTHORISED ELECTRICAL-MECHANICAL TECHNICIANS.
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WARNING! BEFORE REMOVING THE WELDING MACHINE
PANELS AND WORKING INSIDE THE MACHINE MAKE SURE THE
WELDING MACHINE IS SWITCHED OFF AND DISCONNECTED
FROM THE MAIN POWER SUPPLY OUTLET.
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If checks are made inside the welding machine while it is live, this
may cause serious electric shock due to direct contact with live
parts and/or injury due to direct contact with moving parts.
- 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, using a jet of dry
compressed air (max. 10 bar).
- 4 -
2
2
Welding current (A)
min. max.
25 - 50
40 - 80
60 - 110
80 - 160
120 - 200
150 - 250
200 - 350
350 - 550
Fig. I