Hypertherm H401 Power Supplies - Manual (Page 5)

ELECTROMAGNETIC COMPATIBILITY (EMC) AND CE SAFETY
EMC INTRODUCTION
Hypertherm's CE-marked equipment is built
in compliance with standard EN50199. 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 interfer-
ence when the affected equipment is in
close proximity or has a high degree of
sensitivity. In such cases it may be neces-
sary to use other measures to further re-
duce interference.
This plasma 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 electro-
magnetic 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 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 surround-
ing 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
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.
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.
Screening of the entire plasma cutting
installation may be considered for special
applications.
CE Safety
Power supplies are intended for an over
voltage category III power source. See
Section 6.1 of IEC 60974-1.
Power suplies are intended for environ-
mental conditions of pollution degree 3
minimum. See Section 6.1 of IEC 60974-1.
Power supplies must not be used for a
pipe-thawing application. See Section
17N of IEC 60974-1.
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 manu-
facturer'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 con-
nected to the cutting mains supply so that
good electrical contact is maintained be-
tween 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 equip-
ment is in operation. The cutting equipment
should not be modified in any way except for
those changes and adjustments covered in
the manufacturer's instructions. In particu-
lar, 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 compo-
nents bonded to the workpiece will increase
the risk that the operator could receive a
shock by touching these metallic compo-
nents and the electrode at the same time.
The operator should be insulated from all
such bonded metallic components.
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