Tweco 170 HF Weldskill - Manual (Page 19)

WELDSKILL 170 HF INVERTER
3-3 April 23, 2008
3. Computer and other control equipment.
4. Safety critical equipment, e.g. guarding of
industrial equipment.
5. The health of people around, e.g. the use of
pacemakers and hearing aids.
6. Equipment used for calibration and
measurement.
7. The time of day that welding or other activities
are to be carried out.
8. 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.
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.
C. Methods of Reducing Electromagnetic Emis-
sions
1. 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
it’s 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.
2. Maintenance of 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 manufacturer’s instructions. In
particular, the spark gaps of arc striking and
stabilising devices should be adjusted and
maintained according to the manufacturer’s
recommendations.
3. Welding Cables
The welding cables should be kept as short
as possible and should be positioned close
together, running at or close to the floor level.
4. 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 the metallic components and the
electrode at the same time. The operator
should be insulated from all such bonded
metallic components.
5. Earthing of the Workpiece
Where the workpiece is not bonded to earth
for electrical safety, nor connected to earth
because of it’s size and position, e.g. ship’s
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
workpiece 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
direct connection to the workpiece, but in
some countries where direct connection is not
permitted, the bonding should be achieved by
suitable capacitance, selected according to
national regulations.
6. Screening and Shielding
Selective screening and shielding of other
cables and equipment in the surrounding area
may alleviate problems of interference.
Screening the entire welding installation may
be considered for special applications.