Deca T-ARC 527 LAB Manuel D'instruction page 7

the welding operations. Make sure that no part of the electrode holder gripper electric
circuit touches the ground or earth circuits: accidental contact could cause overheating
or trigger a fire.
EMF Electromagnetic Fields
Welding current creates electromagnetic fields (EMF) near the welding circuits and
the welder. Electromagnetic fields may interfere with medical prostheses such as
pacemakers.
Suitable and sufficient measures should be implemented to protect those operators
having such aids. For instance, they should not be allowed to enter that area where
welding equipment is used. Any operator having such aids should consult their doctor
before coming close to an area where welding equipment is used.
This device meets the specific requirements of the product technical standard and is
intended for professional use in an industrial environment only. Compliance to expected
limits for human exposure to electromagnetic fields at home is not ensured.
Follow these strategies to minimise exposure to electromagnetic fields (EMF):
„ Do not place your body between the welding cables. Both welding cables should be on
the same side of your body.
„ Twist both welding cables together and secure them with tape when possible.
„ Do not wrap the welding cables around your body.
„ Connect the earth cable to the workpiece as close as possible to the area to be
welded.
„ Do not work with the welder hanging from your body.
„ Keep your head and trunk as far as possible from the welding circuit. Do not work close
to the welder, or seated or leaning on it. Minimum distance: Fig. 7 Da = cm 50; Db =
cm.20
Class A equipment
This equipment has been designed to be used in professional and industrial
environments.
If this equipment is used in domestic environments and those directly connected to a
low voltage power supply network which supplies buildings used for domestic purposes,
it may be difficult to ensure compliance to electromagnetic compatibility as the result of
conducted or radiated disturbances.
Welding in conditions of risk
„ If welding needs to be done in conditions of risk (electric discharges, suffocation, the
presence of inflammable or explosive materials), make sure that an authorised expert
evaluates the conditions beforehand. Make sure that trained people are present who
can intervene in the event of an emergency. Use the protective equipment described in
5.10; A.7; A.9 of the IEC or CLC/TS 62081 technical specification.
„ If you are required to work in a position raised above ground level, always use a safety
platform.
„ If more than one welding machine has to be used on the same piece, or in any case on
pieces connected electrically, the sum of the no-load voltages on the electrode holders
or on the torches may exceed the safety levels. Make sure that an authorised expert
evaluates the conditions beforehand to see if such risk exists and adopt the protective
measures described in 5.9 of the IEC or CLC/TS 62081 technical specification if
required.
Additional warnings
„ Do not use the welding machine for purposes other than those described, for example
to thaw frozen water pipes.
„ Place the welding machine on a flat stable surface, and make sure that it cannot move.
It must be positioned in such a way as to allow it to be controlled during use but without
the risk of being covered with welding sparks.
„ Do not lift the welding machine. No lifting devices are fitted on the machine.
„ Do not use cables with damaged insulation or loose connections.
Description of the welding machine
The welding machine is a current transformer for manual arc welding using MMA coated
electrodes.
Depending on the model, the welding machine can deliver direct or alternate current.
The electrical characteristic of the transformer is of the falling type.
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. Some welding machines are fitted with a switch that allows you to
select between different supply voltages
C) Welding current adjustment.
D) Current adjustment indicator
E) Thermal cutout signal
F) Couplings for welding cables: direct current (+ -); alternate current (~ ~) (Some
welding machines have directly connected cables).
Technical data
The welding circuit performance have been updated according to the European reference
standard in force since July 2015.
The welding circuit performance are measured in an environment at 40° C. With a lower
temperature performance are higher.
A data plate is affixed to the welding machine. Fig. 2 shows an
A) Constructor name and address.
B) European reference standard for the construction and safety of welding equipment.
C) Symbol of the welding machine internal structure.
D) Symbol of the foreseen welding process.
E) Symbol of delivered current: E1 alternate; E2 direct.
F) Input power required:
950491-06 03/05/16
1˜ alternate single phase voltage; frequency
G) Level of protection from solids and liquids.
H) Symbol indicating the possibility to use the welding machine in environments
potentially subject to electric discharges.
I)
Welding circuit performance.
U0V
I2, U2 Current and corresponding normalised voltage delivered by the welding
X
A / V
J) Power supply data.
U1
I1 eff Effective absorbed current.
I1 max Maximum absorbed current.
K) Serial number
L) Weight
M) Safety symbols: Refer to Safety Warnings.
- Technical data for electrode holder** Fig.8
** (This component may not be included with some models).
Other technical data Fig.2b
Normal use at 20° C for 1 hour.
S) Maximum current and corresponding arc voltage.
T) Usable electrodes.
U) Current delivered by the welding machine.
V) Duty cycle 1 Hour. Indicate how long the welding machine can work for and how
long it must rest for in order to cool down. The time is expressed in % on the basis
of a 1 hour.
Z) Number of electrodes weldable in 1 hour.
„ Connections to the mains must be made by expert or qualified personnel.
„ Make sure that the welding machine is switched off and the plug is not in the power
socket before carrying out this procedure.
„ Make sure that the power socket that the welding machine is plugged into is protected
by safety devices (fuses or automatic switch) and grounded.
„ The device must be connected only to a supply system, with an earthed 'neutral' lead.
Assembly and electrical connections
¾ Assembly the detached parts found in the packaging Fig.6.
¾ Check that the electrical supply delivers the voltage and frequency corresponding to the
welding machine and that it is fitted with a delayed fuse suited to the maximum delivered
rated current (I2max) Fig. 3,1.
L
In order to comply with the requirements set out in the EN61000-3-11 (Fliker) standard,
it is advisable to connect the welder to the supply network interface points having an
impedance lower than the reference Zmax = Fig.3,4.
¾ Plug. If the welding machine is not fitted with a plug, fit a normalised plug (2P+T for 1Ph
and 3P+T for 3Ph) of suitable capacity to the power cable Fig.3,2.
¾ To select two supply voltages in those welding machines fitted with a switch, make sure
that the limit switch is on and allows the use of only one voltage Fig. 4.
L
The welding machines are set to the highest voltage at the factory.
Preparing the welding circuit
¾ Connect the ground lead** to the welding machine and to the piece to be welded, as
close as possible to the point to be welded.
¾ Connect the cable with the electrode holder gripper** to the welding machine and mount
the electrode on the gripper. Refer to the electrode manufacturer's instructions concerning
connection and welding current.
L
In welding machines delivering alternate current, it is not important which connection
the electrode is connected to.
L
In welding machines that deliver direct current, most of the electrodes are connected
to the positive attachment, and only some electrodes (such as Rutile coated ones) are
connected to the negative attachment.
L
The recommended sections (mm2) of the welding cable, based on the maximum
delivered rated current (I2 max), are shown in Fig. 3,3.
** (This component may not be included with some models).
Welding process: description of controls and signals
Once you have put the welding machine into operation, switch it on and carry out the
required adjustments.
Adjusting the welding current
Select the welding current depending on the electrode, the joint and the welding position.
Indicatively, the currents to be used with the different electrode diameters are listed in
Fig. 5.
L
Do not force the adjustment flywheel as this could damage the welding machine. Check
the adjustment on the current adjustment indicator.
L
example of this plate.
To strike the welding arc with the coated electrode, brush it onto the piece to be
welded and as soon as the arc is struck, hold it constantly at a distance equal to the
electrode diameter and at an angle of approximately 20 - 30 degrees in the direction
in which you are welding.
6
Minimum and maximum open circuit voltage (open welding circuit).
machine.
Duty cycle. Indicate how long the welding machine can work for and how
long it must rest for 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).
Current adjustment field and corresponding arc voltage.
Input voltage (permitted tolerance: +/- 10%).
Starting up