Siemens Matsushita Components
587
G
Our product line includes a wide range of ring cores with finely graded diameters ranging from
2,5 to 200 mm (see overview of available types). Other core heights can be supplied on request.
All cores are available in the usual materials.
Ring cores are available in different coating versions, thus offering the appropriate solution for
every application. The coating not only offers protection for the edges but also provides an
insulation function.
The following test setup is used to test the dielectric strength of the insulating coating: A copper
ring is pressed to the top edge of the ring. It touches the ferrite ring at the edges (see diagram).
The test duration is 2 seconds; the test voltages specified in the table are minimum values for
epoxy- and Rilsan-coated cores:
For cores with high permeability, increased spread of the A
L
values of several percent must be ex-
pected according to the specifications due to the Polyamid coating process. This effect can be
avoided by using an epoxy resin coating (L version).
For small ring cores, we have introduced a parylene coating (Galxyl) which features a low coating
thickness and high dielectric strength.
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Ring cores are used primarily for pulse and broadband transformers, baluns and chokes. Owing
to the magnetically closed circuit, high flux densities can be achieved at small volume. Magnetic
leakage is negligible.
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Ring cores are also increasingly used for power applications. Here, the typical values for ampli-
tude permeability and power loss, as summarized in the section on SIFERRIT materials
(page
33
), are applicable to the special power materials.
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Characteristic data for cores not included among the preferred types are available on request.
Core size
U
rms
1,0 kV
1,5 kV
2,0 kV
R 4 thru R 10
R 12,5 thru R 20
> R 20
Ferrite ring
Metal poles
U
rms
Ring Cores
General Information