EMC Suitable Wiring
63
05/01 AWB2700-1384GB
5
Radiation Coupling:
A radiation coupling occurs if an electromagnetic wave hits a
conductive structure. Each wave-hit induces currents and voltages.
Typical sources are, e.g., spark gaps (ignition plugs, electro-motor
commutators) and transmitters (e.g. walkie-talkies), that are used
near the concerned conductive structure.
Guarantee of EMC
EMC is guaranteed if the following basic guidelines are considered.
• Correct and large-surface grounding of inactive metal
components
• Correct Shielding of lines and devices
• Proper cable routing - correct wiring
• Creation of a standard reference potential and grounding of all
electric operating devices
• Special EMC measures for particular applications
Grounding of Inactive Metal Components
Overview
All inactive metal components have to be connected to each other
extensively and with a low impedance (grounding). These measures
ensure a standard reference potential for all control elements and
therefore help to cut out coupling disturbances. Inactive metal
components are those parts which are conductive, but are
separated electrically from other components by ground insulation;
therefore only in the case of an error or malfunction can they
conduct a voltage.
The ground should never - not even in case of an error - be able to
adopt a dangerous contact voltage. In order to avoid this, the
ground must be connected to a protective conductor. Remote
grounded components (e.g. cabinets) must be connected to the
protective conductor system in a star-shaped configuration to avoid
ground circuits.
Before installation starts, screw connections on varnished, painted
or anodised metal components have to be fitted with either special
contact disks or the points of contact have to be cleaned down to
the metal. Once the connection is established, all points of contact
must be protected against corrosion (e.g. by using grease).
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