Hypertherm HD3070 Plasma Arc Cutting System w/ Automatic Gas Console - Manual (Page 274)

f-2 HD3070 with Automatic Gas Console Instruction Manual
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APPENDIX F
EMC INTRODUCTION
This plasma cutting equipment has been built in
compliance with standard EN50199. To ensure
that the equipment works in a compatible man-
ner with other radio and electronic systems, the
equipment should be installed and used in
accordance with the information below to
achieve electromagnetic compatibility.
The limits required by EN50199 may not be
adequate to completely eliminate interference
when the affected equipment is in close
proximity or has a high degree of sensitivity. In
such cases it may be necessary to use other
measures to further reduce interference.
This plasma equipment should be used only in
an industrial environment. It may be difficult to
ensure electromagnetic compatability in a
domestic environment.
INSTALLATION AND USE
The user is responsible for installing and using
the plasma equipment according to the manu-
facturers instructions.If electromagnetic disturb-
ances are detected then it shall be the
responsibility of the user to resolve the situation
with the technical assistance of the manu-
facturer. In some cases this remedial action
may be as simple as earthing the cutting circuit,
see Earthing of Workpiece. In other cases it
could involve constructing an electromagnetic
screen enclosing the power source and the
work complete with associated input filters. In all
cases electromagnetic disturbances must be
reduced to the point where they are no longer
troublesome.
ASSESSMENT OF AREA
Before installing the equipment the user shall
make an assessment of potential electromag-
netic problems in the surrounding area. The
following shall be taken into account:
a. Other supply cables, control cables,
signalling and telephone cables; above, below
and adjacent to the cutting equipment.
b. Radio and television transmitters and
receivers.
c. Computer and other control equipment.
d. Safety critical equipment, for example guard-
ing of industrial equipment.
e. Health of the people around, for example the
use of pacemakers and hearing aids.
f. Equipment used for calibration or
measurement.
g. Immunity of other equipment in the environ-
ment. User shall ensure that other equipment
being used in the environment is compatible.
This may require additional protection measures.
h. Time of day that cutting 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
Cutting equipment should be connected to the
mains supply according to the manufacturers
recommendations. If interference occurs, it may
be necessary to take additional precautions
such as filtering of the mains supply. Consid-
eration should be given to shielding the supply
cable of permanently installed cutting equip-
ment, in metallic conduit or equivalent. Shield-
ing 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 power source enclosure
Maintenance of Cutting Equipment
The cutting equipment should be routinely
maintained according to the manufacturers
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 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.
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 components
bonded to the workpiece 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 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 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 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 circuits of other equipment. Further
guidance is given in IEC TC26 (sec)94 and IEC
TC26/108A/CD Arc Welding Equipment
Installation and Use.
Screening and Shielding
Selective screening and shielding of other
cables and equipment in the surrounding area
may alleviate problems of interference. Screen-
ing of the entire plasma cutting installation may
be considered for special applications.