PRECAUTIONS TO ELECTROMAGNETIC COMPATIBILITY
1 General
Welding may cause electromagnetic interference.
The interference emission of arc welding equipment can be minimized by adopting proper installa-
tion method and correct use method.
The products described in this manual belong to the limit of class A equipment (applies to all occa-
sions except the residential areas powered by public low-voltage power system).
Warning
: Class A equipment does not apply to the residential areas powered by public low-voltage
power system. Because the electromagnetic compatibility cannot be guaranteed in these areas
owing to conducted and radiated disturbances.
2 Environmental assessment suggestions
Before installing the arc welding equipment, user shall assess the potential electromagnetic distur-
bance problems in the surrounding environment. The following matters shall be considered:
- Whether there are other service cables, control cables, signal and telephone wires, etc. above,
under or around the welding equipment;
- Whether there are radio and television transmitting and receiving devices;
- Whether there are computers and other control equipment;
- Whether there are high-security level equipment, such as industrial protective equipment;
- Consider the health of staff at the site, for example, where there are workers wearing hearing aid or
pacemaker;
- Whether there are equipment used for calibration or inspection;
- Pay attention to the noise immunity of other equipment around. The user should ensure that the
equipment is compatible with the surrounding equipment, which may require extra protective
measures;
- Time for welding or other activities;
The range of environment shall be determined according to the building structure and other possible
activities, which may exceed the boundary of building.
3 Methods to reduce emission
- Public power supply system
The arc welding equipment shall be connected to the public power supply system according to
the method recommended by the manufacturer. If there is interference, additional preventive
measures shall be taken, such as access with fi lter in the public power supply system. For fi xed arc
welding equipment, the service cables shall be shielded by metal pipe or other equivalent meth-
ods. However, the shield shall ensure electrical continuity and shall be connected with the case of
welding source to ensure the good electrical contact between them.
- Maintenance of arc welding equipment
The arc welding equipment must be regularly maintained according to the method recommend-
ed by the manufacturer. When the welding equipment is running, all entrances, auxiliary doors
and cover plates shall be closed and properly tightened. The arc welding equipment shall not be
modifi ed in any form, unless the change and adjustment are permitted in the manual. Particularly,
the spark gap of arc striker and arc stabilizer shall be adjusted and maintained according to the
manufacturer’s suggestions.
- Welding cable
The welding cable shall be as short as possible and close to each other and to the ground line.
- Equipotential bonding
Pay attention to the bonding of all metal objects in surrounding environment. The overlapping of
metal object and workpiece can increase the risk of work, as operators may suffer from electric
shock when touch the metal object and electrode simultaneously. Operators shall be insulated from
all these metal objects.
- Grounding of the workpiece
For electrical safety or workpiece location, size and other reasons, the workpiece may not be
grounded, such as the hull or structural steelwork. Grounding of workpieces sometimes can reduce
the emission, but it is not always the case. So be sure to prevent the increasing risk of electric shock
or damage of other electrical equipment caused by grounded workpieces. When necessary, the
workpiece should be directly connected with the ground. But direct grounding is forbidden in some
countries. In such case, use appropriate capacitor in accordance with regulations of the country.
- Shielding
Selectively shield the surrounding equipment and other cables to reduce the electromagnetic inter-
ference. For special applications, the whole welding area can be shielded.
SK-5
