REO EMC-Filters

Things worth knowing about EMC filters
Collective suppression
Individual suppression
There is an economic advantage in planning the optimal suppression of interference. The number of filters
required can be minimized by simultaneously suppressing interference in several devices, say in a switch cabinet.
Problems with collective suppression
Such a solution is problematic when additional components have to be installed.
The nominal current of the filter must not be exceeded. Lengthy connecting leads have to be shielded and the
power-consuming devices are not isolated - so possible unwanted interaction may occur.
Because of this problem, individual suppression is usually more economic.
Nominal current, maximum continuous operating current and ambient temperature
The nominal current is the maximum continuous operating current at 100% load, with correct installation, mains
frequency of 50/60 Hz, and a maximum permissible ambient temperature of 40°C. The permissible continuous
operating current falls off at a higher ambient temperature, or with loads that generate mains harmonics, e.g.
phase-angle controls, triacs, semiconductor relays or primary switched-mode power supplies. Brief overcurrents
are permissible if they are followed by a correspondingly lower current load, but this must always be tested
individually.
Fall-off in current at temperatures above 40°C
The permissible current carrying capacity is a function of ambient temperature. At temperatures of up to 40°C, a
filter can be operated at its nominal current.
At higher temperatures, the permissible
current falls off. At 85°C, the zero point for
the current load is reached.
Environment
40°C 85°C
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