1.0 Safety.
Caution: Plasma cutters are a source of life-threatening voltage (in
HF/HV models it can exceed 10,000V) and generate very high interference
which can disturb or damage the electronics (computer, controller,
controllers). Assembly and connection should be carried out by a
person with electrical qualifications.
Failure to make good contact between the material/ground clamp
terminal and the material to be cut can lead to irreparable damage to
electronic equipment.
1.1 Grounding, shielding
Protective earthing is used to discharge the dangerous potential of
the plasma arc to earth. The resistance to earth of the structure should
not exceed ΩIt is important not to make a ground loop. The
disturbance/overvoltage should have only one way of escaping to earth and
it is unacceptable for it to have an output to earth through electronic
components. This can be implemented by electrically separating the
control part from the machine structure and connecting it to earth via a
separate conductor ( usually the PE protective earth of the mains supply -
via the electronics supply cable ).
When connecting the protective earthing of the control box to the
machine structure ( i.e. using the same earthing as the structure ), do not
use any other earthing source that could create a ground loop.
In order to minimise the influence of interference, the plasma source
as well as the torch cable should be placed as far as possible from the
control cables and the computer. The use of shielded cables, the shields of
which are connected to the earth bar only on the control box side, will
considerably reduce the influence of interference on the operation of the
machine (see example diagram 2.0).
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