Hypertherm THC ArcGlide - Manual (Page 31)

Safety and Compliance SC-31
Electromagnetic Compatibility (EMC)
Introduction
Hypertherm’s CE-marked equipment is built in compliance with standard
EN60974-10. The equipment should be installed and used in
accordance with the information below to achieve electromagnetic
compatibility.
The limits required by EN60974-10 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 cutting equipment is designed for use only in an industrial
environment.
Installation and use
The user is responsible for installing and using the plasma equipment
according to the manufacturer’s instructions.
If electromagnetic disturbances are detected then it shall be the
responsibility of the user to resolve the situation with the technical
assistance of the manufacturer. In some cases this remedial action may
be as simple as earthing the cutting circuit, see
Earthing of the
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 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 cutting equipment.
b. Radio and television transmitters and receivers.
c. Computer and other control equipment.
d. Safety critical equipment, for example guarding 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 environment. 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 must 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 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 power 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 components 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 the 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 steel work, 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.