Clarke Arc/Tig135, Operating & Maintenance Instructions

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8
ELECTROMAGNETIC INTERFERENCE (EMC) IN
THE WORKPLACE
Whilst this unit complies with EMC regulations, the user is responsible for installing and using the
welding equipment according to the manufacturers instructions. If electromagnetic disturbances
are detected then it shall be the responsibility of the user of the welding equipment to resolve the
situation. In some cases this remedial action may be as simple as earthing the welding circuit,
see ‘Note’. 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.
Note - The welding circuit may or may not be earthed for safety reasons.
Changing the earthing arrangements should only be authorised by a person who
is competent to assess whether the changes will increase the risk of injury, e.g.
by allowing parallel welding current return paths which may damage the earth
circuits of other equipment.
1 ASSESSMENT OF THE WELDING AREA
Before installing welding equipment the user shall make an assessment of potential
electromagnetic problems in the surrounding area. Avoid using your inverter in the vicinity of:
a) other supply cables, control cables, signalling and telephone cables; above, below and
adjacent to the welding equipment;
b) radio and television transmitters and receivers;
c) computer and other control equipment;
d) safety critical equipment, e.g. guarding of industrial equipment;
e) pacemakers and hearing aids etc;
f) equipment used for calibration or measurement;
g) 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.
It may be possible to avoid the above by changing the time of day that welding 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.
2 REDUCING EMC EMISSIONS
2.1 Mains Supply
Welding 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. 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 its length. The shielding should be connected to the welding