Lincoln Electric APEX 3 Series Operator's Manual page 6

APEX ® 3 SERIES TIG PENDANT MANUAL
ELECTROMAGNETIC
COMPATIBILITY (EMC)
CONFORMANCE
Products displaying the CE mark are in conformity with European Community
Council Directive of 3 May 1989 on the approximation of the laws of the
Member States relating to electromagnetic compatibility (89/336/EEC). It
was manufactured in conformity with a national standard that implements a
harmonized standard: EN 60974-10
Electromagnetic Compatibility (EMC) Product Standard for Arc Welding
Equipment. It is for use with other Lincoln Electric equipment. It is designed
for industrial and professional use.
INTRODUCTION
All electrical equipment generates small amounts of electromagnetic
emission. Electrical emission may be transmitted through power lines or
radiated through space, similar to a radio transmitter. When emissions are
received by other equipment, electrical interference may result. Electrical
emissions may affect many kinds of electrical equipment; other nearby
welding equipment, radio and TV reception, numerical controlled machines,
telephone systems, computers, etc. Be aware that interference may result
and extra precautions may be required when a welding power source is used
in a domestic establishment.
INSTALLATION AND USE
The user is responsible for installing and using the welding equipment
according to the manufacturer's instructions. If electromagnetic disturbances
are detected then it shall be the responsibility of the user of the welding
equipment to resolve the situation with the technical assistance of the
manufacturer. In some cases this remedial action may be as simple as
earthing (grounding) the welding circuit, see Note. In other cases it could
involve construction of an electromagnetic screen enclosing the power source
and the work complete with associated input filters. In all cases electro-
magnetic disturbances must be reduced to the point where they are no longer
troublesome.
Note: The welding circuit may or may not be earthed for safety reasons according to national codes.
Changing the earthing arrangements should only be authorized by a person who is competent to
access whether the changes will increase the risk of injury, e.g., by allowing parallel welding current
return paths which may damage the earth circuits of other equipment.
ASSESSMENT OF AREA
Before installing welding equipment the user shall make an assessment of
potential electromagnetic problems in the surrounding area. The following
shall be taken into account:
a
. other supply cables, control cables, signaling and telephone cables; above, below
and adjacent to the welding equipment;
b. radio and television transmitters and receivers;
c. computer and other control equipment;
d. safety critical equipment, e.g., guarding of industrial equipment;
e. the health of the people around, e.g., the use of pacemakers and hearing aids;
f. equipment used for calibration or measurement
g. the immunity of other equipment in the environment. The user shall ensure that other
equipment being used in the environment is compatible. This may require additional
protection measures;
h. the time of day that welding or other activities are to be carried out.
The size of the surrounding area to be considered will depend on the
structure of the building and other activities that are taking place. The
surrounding area may extend beyond the boundaries of the premises.
METHODS OF REDUCING EMISSIONS
Mains Supply
Welding equipment should be connected to the mains supply according
to the manufacturer's recommendations. If interference occurs, it may be
necessary to take additional precautions such as filtering of the mains supply.
Consideration should be given to shielding the supply cable of permanently
installed welding equipment, in metallic conduit or equivalent. Shielding
should be electrically continuous throughout its length. The shielding should
be connected to the welding power source so that good electrical contact is
maintained between the conduit and the welding power source enclosure.
Maintenance of the Welding Equipment
The welding equipment should be routinely maintained according to the
manufacturer's recommendations. All access and service doors and covers
should be closed and properly fastened when the welding equipment is in
operation. The welding equipment should not be modified in any way except
for those changes and adjustments covered in the manufacturers instructions.
In particular, the spark gaps of arc striking and stabilizing devices should be
adjusted and maintained according to the manufacturer's recommendations.
Welding Cables
The welding cables should be kept as short as possible and should be
positioned close together, running at or close to floor level.
Equipotential Bonding
Bonding of all metallic components in the welding installation and adjacent
to it should be considered. However, metallic components bonded to the
work piece will increase the risk that the operator could receive a shock by
touching these metallic components and the electrode at the same time. The
operator should be insulated from all such bonded metallic components.
Earthing of the Workpiece
Where the workpiece is not bonded to earth for electrical safety, not
connected to earth because of its size and position, e.g., ships hull or
building steelwork, a connection bonding the workpiece to earth may reduce
emissions in some, but not all instances. Care should be taken to prevent the
earthing of the work piece increasing the risk of injury to users, or damage to
other electrical equipment. Where necessary, the connection of the workpiece
to earth should be made by a direct connection to the work piece, but in some
countries where direct connection is not permitted, the bonding should be
achieved by suitable capacitance, selected according to national regulations.
Screening and Shielding
Selective screening and shielding of other cables and equipment in the
surrounding area may alleviate problems of interference. Screening of the
entire welding installation may be considered for special applications.
1 Portions of the preceding text are contained in EN 60974-10: "Electromagnetic
Compatibility (EMC) product standard for arc welding equipment."
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SAFETY