Hypertherm HRT - Manual (Page 6)

ElEctromagnEtic compatibility (Emc)
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EMC-2 Compliance Information
such as filtering of the mains supply.
Consideration should be given to shielding the
supply cable of permanently installed cutting
equipment, in metallic conduit or equivalent.
Shielding should be electrically continuous
throughout its length. The shielding should be
connected to the cutting mains supply so that
good electrical contact is maintained between
the conduit and the cutting pow er source
enclosure.
Maintenance of cutting equipment
The cutting equipment must be routinely
maintained according to the manufacturer’s
recommendations. All access and service doors
and covers should be closed and properly
fastened when the cutting equipment is in
operation. The cutting equipment should not
be modified in any way except as set forth in
and in accordance with the manufacturer’s
written instructions. For example, the spark gaps
of arc striking and stabilizing devices should
be adjusted and maintained according to the
manufacturer’s recommendations.
Cutting cables
The cutting cables should be kept as short
as possible and should be positioned close
together, running at or close to the floor level.
Equipotential bonding
Bonding of all metallic components in the
cutting installation and adjacent to it should
be considered. However, metallic com po nents
bonded to the workpiece will increase the risk
that the operator could receive a shock by
touching these metallic components and the
electrode (nozzle for laser heads) at the same
time. The operator should be insulated from all
such bonded metallic components.
Earthing of workpiece
Where the workpiece is not bonded to earth
for electrical safety, nor connected to earth
because of its size and position, for example,
ship’s hull or building steelwork, a connection
bonding the work piece to earth may reduce
emis sions 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
a direct connection to the workpiece, but in
some countries where direct connection is not
permitted, the bonding should be achieved by
suitable capacitances selected according to
national regulations.
Note: the cutting circuit may or may not
be earthed for safety reasons. Changing
the earthing arrangements should only be
authorized by a person who is competent to
assess whether the changes will increase the
risk of injury, for example, by allowing parallel
cutting current return paths which may damage
the earth cir cuits of other equipment. Further
guidance is provided in IEC 60974‑9, Arc
Welding Equip ment, Part 9: Installation and
Use.
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 plasma cutting
installation may be con sid ered for special
applications.