MPP toroidal cores are manufactured from an alloy powder
comprising 80% nickel, 2% molybdenum and the balance iron, utilizing
distributed air gap technology. The alloy powder is produced by means of
mechanical or chemical atomisation, prior to being mixed in an aqueous process
with inorganic silicates and oxides so that each particle is coated with a
layer to prevent electrical contact during and subsequent to the compacting
process. The powder is dried and stored in a controlled atmosphere.
The compacting process produces the required shape and size of
component by pressing calculated amounts of powder in a die at considerable
mechanical pressures, resulting in component densities of 7-8g/cm3. Further
processing, which includes heat treatment and radius forming, produces the
highly controlled physical and magnetic properties this material exhibits. The
toroidal cores are then painted with an epoxy resin which forms a resilient
moisture- and solvent-fast finish, having excellent dielectric properties.
The result is a product offered in a range of sizes and
permeabilities with a high saturation flux density (up to 0.7 tesla), high
curie temperature, good thermal stability and low hysterisis and eddy current
loss. It also exhibits excellent magnetic stability to DC magnetisation.
- Typical applications include:-
- Low and band pass filters
- SMPS transformers
- Loading coils
- RFI filters
The High Flux (H grade) follows a similar manufacture and
process route to the MPP grade material, except that the composition is 50%
nickel and 50% iron. This variation results in a material suitable for high
saturation flux density applications (up to 1.5 tesla), whilst still
maintaining a considerably lower core loss than that of powdered iron. A
further advantage over powdered iron is less change of permeability due to AC
excitation, DC bias and temperature.
- Typical applications include:
- SMPS energy storage filter inductors
- RFI suppression filters
- Noise filter