11.98
Connection
Siemens AG 67087-6AC85-0AA0
ENGLISH
3-7
Common Rectifier Operating instructions
3.4
Measures for keeping to RFI suppression regulations
The following points must be observed in order to comply with the radio-frequency interference suppression
requirements:
•
Grounding
Radio frequency interference results from operation of the converters. Such interference voltages should be
returned to the source by means of low-resistance connections (cross-section of the ground connection
cross-section of the power supply system connection).
On installation of the power supply unit and of any optional RFI filters use should be made of the best
available method of grounding (e.g. mounting plate, earthing wire, earthing bus). Connect all conductive
housings together so as to make contact over a large area.
Not only the cross-section (governed also by the safety regulations which should be observed to obviate the
effects of a fault) but also the contact surfaces are of vital importance for RFI suppression, since high
frequency interference currents do not flow through the entire cross-section but mainly on the outer surface
of the conductor.
•
Shielding
The following measures are required in order to attenuate interference and to meet the RFI suppression
requirements
−
use of shielded cable between the output of the converter and the motor and
−
use of shielded control cables.
The shield must be connected to earth potential at both ends.
•
Filters
The RFI suppression filters must be connected directly before the power supply unit. The housings must be
interconnected by means of an electrically conductive connection.
Type A1 RFI suppression filters are recommended for compliance with the RFI suppresssion requirements.
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