MMG offers two ranges of Iron Powder cores- High frequency powder cores for applications
in high Q inductors and wide-band matching transformers, and high permeability powder cores
with applications in SMPS chokes, RFI suppression, and light dimmers. Components available
include toroidal cores, rods, tubes, axial leaded chokes (coilforms), screw cores
and E cores.
Iron powder cores are pressed from selected grades of iron mixed with a bonding material.
High resistivity is required to reduce the eddy current losses and for this purpose the iron
powder is subjected to an acid treatment to produce an insulating layer on the
surface of each individual particle. A feature of the manufacturing process is
that minute air gaps occur between the particles causing the permeability of the iron to
be severely reduced. Because of these gaps it is difficult to saturate iron powder cores,
especially those operating in an open magnetic circuit. The optimum frequency ranges
and initial permeabilities of the grades of iron powder are indicated below.
|
