12
EMC Device Clas-
sifications
EMC measures
EMF measures
Devices in emission class A:
-
Are only designed for use in industrial settings
-
Can cause line-bound and radiated interference in other areas
Devices in emission class B:
-
Satisfy the emissions criteria for residential and industrial areas.
This is also true for residential areas in which the energy is sup-
plied from the public low-voltage mains.
EMC device classification as per the rating plate or technical data.
In certain cases, even though a device complies with the standard limit values
for emissions, it may affect the application area for which it was designed (e.g.
when there is sensitive equipment at the same location, or if the site where the
device is installed is close to either radio or television receivers).
If this is the case, then the operator is obliged to take appropriate action to rec-
tify the situation.
Check and evaluate the immunity to interference of nearby devices according
to national and international regulations. Examples of equipment that may be
susceptible to interference from the device include:
-
Safety devices
-
Power, signal and data transfer lines
-
IT and telecommunications devices
-
Measuring and calibrating devices
Supporting measures for avoidance of EMC problems:
1.
Mains supply
-
If electromagnetic interference arises despite correct mains connec-
tion, additional measures are necessary (e.g. use a suitable line fil-
ter).
2.
Welding power leads
-
must be kept as short as possible
-
must run close together (to avoid EMF problems)
-
must be kept well apart from other leads
3.
Equipotential bonding
4.
Earthing of the workpiece
-
If necessary, establish an earth connection using suitable capacitors.
5.
Shielding, if necessary
-
Shield off other nearby devices
-
Shield off entire welding installation
Electromagnetic fields may pose as yet unknown risks to health:
-
effects on the health of others in the vicinity, e.g. wearers of pacemakers
and hearing aids
-
wearers of pacemakers must seek advice from their doctor before ap-
proaching the device or any welding that is in progress
-
for safety reasons, keep distances between the welding cables and the
welder's head/torso as large as possible
-
do not carry welding cables and hosepacks over the shoulders or wind
them around any part of the body
