Nanocrystalline Replaces High Perm Ferrite in Common Mode Chokes

Nanocrystalline Replaces High Perm Ferrite in Common Mode Chokes

MH&W International Corporation offers a large range of Nanocrystalline NANOPERM® toroidal cores for common mode chokes.

The main requirement on a EMC filter choke is high impedance.  Useful characteristics of NANOPERM® are high permeability of up to a factor of 10 over ferrite, higher saturation induction, and extended working temperature  up to 180°C.

There are significant advantages of Nanocrystalline material over 10K and 15K perm ferrite.  10k and 15k perm ferrite material are difficult to manufacture and difficult to keep within spec.  Nanocrystalline has a volume reduction of 60%, and weight reduction of 65% over typical ferrite chokes.  Especially critical in space and weight limitations.

10K Perm Ferrite 15K Perm Ferrite Nanocrystalline
Saturation Flux Density 400 mT 360 mT 1,200 mT
Curie Temperature 120°C 105 °C 600C
Core Loss High High Low ( >110W/Kg)
Magnetostriction/Vallari Effect Susceptible Highly Susceptible No apparent effect
Nanocrystalline is available with Permeabilities of 1,000 to 90,000.

MH&W keeps stock of some of the more common sizes of Nanocrystalline toroids.  Here is a table of the most prevalent Nanocrystalline toroids.

Part Number OD ID TH Aℓ (nH) Aℓ Freq Aℓ min Aℓ max
M-003 25 16 10 67000 10KHz 45000 89000
M-061 25 20 10 10800 10KHz 6600 15000
M-062 25 16 10 20550 10KHz 13700 27400
M-076 20 12.5 8 14600 10KHz 9700 19500
M-224 24 15 8 15500 10KHz 10000 21000
M-449 25 16 10 4900 100KHz 3800 6000
M-450 30 20 10 4750 100KHz 3500 6000
M-306 16 11 5 8850 10KHz 5900 11800
M-307 20 15 5 6800 10KHz 4500 9100
M-308 25 20 5 5250 10KHz 3500 7000
M-309 30 25 5 4250 10KHz 2800 5700
M-310 40 35 5 3150 10KHz 2100 4200
Graphs (click thumbnail for larger image):

  1. Saturation as a Function of Temperature

  2. Permeability as a Function of Temperature

  3. Permeability as a Function of Frequency

    http://www.mhw-intl.com/wp-content/uploads/2017/08/PermeabilityAsFunctionOfFrequency.png“>

  4. Similar Impedance with Smaller Core

  5. Typical Impedance 30mm, 22 Turn Coil

    http://www.mhw-intl.com/wp-content/uploads/2017/08/TypicalImpedance-300×202.png” alt=”” width=”300″ height=”202″ />

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