Siemens SIMATIC MOBY D System Manual page 72

Planning the MOBY D system
4.5 EMC Guidelines
Interference sources
In order to achieve a high level of electromagnetic compatibility and thus a very low level of
disturbance in a plant, it is necessary to recognize the most frequent interference sources.
These must then be eliminated by appropriate measures.
Table 4- 25
Interference source
Contactors,
electronic valves
Electrical motor
Electric welding device
Power supply unit, switched-
mode
High-frequency appliances
Transmitter
(e.g. service radio)
Ground or reference potential
difference
Operator
Power cable
High-voltage cable
72
Interference sources: origin and effect
Interference results from
Contacts
Coils
Collector
Winding
Contacts
Transformer
Circuit
Circuit
Antenna
Voltage difference
Static charge
Current flow
Voltage difference
Effect on the interference sink
System disturbances
Magnetic field
Electrical field
Magnetic field
Electrical field
Magnetic field, system disturbance,
transient currents
Electrical and magnetic field, system
disturbance
Electromagnetic field
Electromagnetic field
Transient currents
Electrical discharge currents, electrical
field
Electrical and magnetic field, system
disturbance
Electrical field
System Manual, 01/2010, J31069-D0147-A6-7618
MOBY D