ELECTROMAGNETIC EMISSIONS
The electric current flowing through any conductor causes electrical and magnetic fields (EMF). The welding current generates
an EMF around the welding circuit and the welding equipment.
The EMF electromagnetic fields can interfere with certain medical implants, such as pacemakers. Protection measures must be taken for people having
medical implants. For example, by restricting access to passers-by or conducting an individual risk evaluation for the welders.
All welders should take the following precautions in order to minimise exposure to the electromagnetic fields (EMF) generated by the welding circuit::
• position the welding cables together – if possible, attach them;
• keep your head and chest as far as possible from the welding circuit;
• never wrap the cables around your body;
• never position your body between the welding cables. Hold both welding cables on the same side of your body;
• connect the earth clamp as close as possible to the welding area;
• do not work too close to, do not sit on and do not lean on the welding machine
• do not weld when you're carrying the welding machine or its wire feeder.
People wearing pacemakers are advised to consult a doctor before using this device.
Exposure to electromagnetic fields while welding may have other health effects which are not yet identified.
RECOMMENDATIONS FOR EVALUATING THE WELDING AREA AND INSTALLATION
Overview
The user is responsible for the installation and use of the arc welding equipment according to the manufacturer's instructions. If electromagnetic
disturbances are detected, the user is responsible for resolving the situation with the manufacturer's technical assistance. In some cases, this
corrective action may be as simple as earthing the welding circuit. In other cases, it may be necessary to construct an electromagnetic shield around
the welding power source and around the entire piece by fitting input filters. In all cases, electromagnetic interferences must be reduced until they
are no longer inconvenient.
Welding area assessment
Before installing the machine, the user must evaluate the possible electromagnetic problems that may arise in the area where the installation is
planned.
. The following elements should be taken into account:
a) the presence (above, below and next to the arc welding machine) of other power cables, remote cables and telephone cables;
b) television transmitters and receivers;
c) computers and other hardware;
d) critical safety equipment such as industrial machine protections;
e) the health and safety of the people in the area such as people with pacemakers or hearing aids;
f) calibration and measuring equipment;
g) the isolation of other pieces of equipment which are in the same area.
The user has to ensure that the devices and pieces of equipment used in the same area are compatible with each other. This may require extra
precautions;
h) the time of day during the welding or other activities have to be performed.
The surface of the area to be considered around the device depends on the the building's structure and other activities that take place there. The area
taken into consideration can be larger than the limits of the instalations.
Welding area assessment
Besides the welding area assessment, the assessment of the arc welding systems intalation itself can be used to identify and resolve cases of
disturbances. The assessment of emissions must include in situ measurements as specified in Article 10 of CISPR 11: 2009. In situ measurements can
also be used to confirm the effectiveness of mitigation measures.
RECOMMENDATION ON METHODS OF ELECTROMAGNETIC EMISSIONS REDUCTION
a. National power grid: the arc welding machine must be connected to the national power grid in accordance in accordance with the manufacturer's
recommendation. In case of interferences, it may be necessary to take additional precautions such as the filtering of the power supply network.
Consideration should be given to shielding the power supply cable in a metal conduit or equivalent of permanently installed arc welding equipment..
It is necessary to ensure the electrical continuity of the shielding along its entire length. The shielding should be connected to the welding current
source to ensure a good electrical contact between the conduit and the casing of the welding current source.
b. Maintenance of the arc welding equipment: The arc welding machine should be subject to a routine maintenance check according to the
recommendations of the manufacturer. All accesses, service doors and covers should be closed and properly locked when the arc welding equipment
is on. The arc welding equipment must not be modified in any way, except for the changes and settings outlined in the manufacturer's instructions.
The spark gap of the arc start and arc stabilization devices must be adjusted and maintained according to the manufacturer's recommendations.
c. Welding cables: Cables must be as short as possible, close to each other and close to the ground, if not on the ground.
d. Equipotential bonding: consideration should be given to bonding all metal objects in the surrounding area. However, metal objects connected
to the workpiece increase the risk of electric shock if the operator touches both these metal elements and the electrode. It is necessary to insulate
the operator from such metal objects.
e. Earthing of the workpiece: When the part is not earthed due to electrical safety reasons or because of its size and its location (which is the case
with ship hulls or metallic building structures), the earthing of the part can, in some cases but not systematically, reduce emissions. It is preferable
to avoid the earthing of parts that could increase the risk of injury to the users or damage other electrical equipment. If necessary, it is appropriate
that the earthing of the part is done directly, but in some countries rules may not allow such a direct connection, it is appropriate that the connection
is made with a capacitor selected according to national regulations.
f. Protection and shielding: The selective protection and shielding of other cables and devices in the area can reduce perturbation issues. The
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protection of the entire welding area can be considered for specific situations.
AUTOPULSE 220
EN