
Coupling mechanism
Cause
Typical source
Galvanic coupling
Galvanic or metallic coupling
always occurs, when two cur-
rent circuits have a common
line.
n
Pulsed devices (Net influ-
ence from transducers and
foreign net devices)
n
Starting motors
n
Different potential of com-
ponent cubicles with
common current supply
n
Static discharges
Capacitate coupling
Capacitate or electric coupling
occurs between conductors
with different potential. The
coupling is proportionate to the
temporal change of the
voltage.
n
Interference through par-
allel signal lines
n
Static discharge of the per-
sonnel
n
Contactors
Inductive coupling
Inductive or magnetic coupling
occurs between two current
active line loops. The magnetic
flows associated with the cur-
rents induct interference vol-
tages. The coupling is propor-
tional to the time related
change of the current.
n
Transducers, motors, elec-
tric welding devices
n
Parallel net cables
n
Cables with toggled cur-
rents
n
Signal cable with high fre-
quency
n
Unused coils
Radiate power coupling
One talks of radiate power cou-
pling, when an electromagnetic
wave meets a line circuit. The
hit of the wave inducts currents
and voltages.
n
Sender in the neighbour-
hood (e.g. walkie-talkie)
n
Sparking lines (sparking
plugs, collector of electric
motors, welding devices)
VIPA HMI
Installation guidelines
Basic rules for the EMC-equitable assembly of installations
HB160 | PPC | 67P-PNL0 | GB | 16-42
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