toroidal inductor shape

Discussion in 'The Projects Forum' started by mah, Mar 21, 2014.

  1. mah

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    Mar 15, 2010
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    Last edited: Mar 21, 2014
  2. bertus

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  3. RamaD

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    Is the color Yellow? And what is the color on the other side?
    Both Yellow/White & Yellow/Clear (what ever that clear means?) are Powdered Iron Cores. The link points to params matching with Yellow/Clear.
    The following link gives dimensions, color, AL values, etc., on ferrite & powdered Iron toroids.
    http://catzco.com/toroids.htm
     
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  4. mah

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  5. bertus

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    Hello,

    As RamonD asked, are there other colors on the core?
    There are 3 different yellow types.
    Yellow/blank : type 6
    Yellow/blue : type 17 and
    Yellow/white : type 26

    Bertus
     
  6. GopherT

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    If it is a Micrometals brand core, it is iron powder.

    Micrometals tried to copyright their color codes years ago so, if it is not Micrometals brand, then there is no way to know the material based on color (assuming Micrometals has been able to enforce their copyright).

    Here is a link to the various iron powder mixes that Micrometals uses with properties.

    http://www.micrometals.com/materials_index.html
     
  7. Experimentonomen

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    Did you get the core from a computer power supply ? Then it is a T106-26 irom powder core from micrometals.
     
  8. mah

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    it is yellow i don't remember the other side as it is n't with me now but i think it is all yellow .
     
  9. mah

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    i just want to make inductor for buck converter with 150 uH and it could handle 6 Ampere , is there any way to find out the properties of my core and and use the turnings to design it?
     
  10. GopherT

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    There used to be a calculator on the Micrometals website.
     
  11. GopherT

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    If it is an old power supply then, yes. If it is less than 10 years old, don't count on it. There is plenty of competition from china and Korea since 2005.
     
  12. burger2227

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    Feb 3, 2014
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    Toroid is a shape: http://en.wikipedia.org/wiki/Toroid

    Ferrite means iron. Making an inductor coil from either is always questionable...it often depends on the core and the size of the wire.
     
  13. GopherT

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    No, iron means elemental iron while ferrite means a ferromagnetic iron oxide ceramic. Ferrites have much higher permeability while iron can handle much higher current before saturation.
     
  14. RamaD

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    Of the 3, Yellow/White has the maximum AL value, others are almost a tenth! As Experimentonomen said, if it is from SMPS, you can assume it to be #26. Even with that you would require 40 turns to get close to 150uH, winding that can stand 6A. It will be multilayer, so will increase capacitance. The flux turns out to be around 0.35T which is not a problem.
     
  15. mah

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    the core i have is yellow/white with outer dia=1.1 inch, inner dia=.6 inch so i think that should be T-106 26 if i want to do 500uH i should wire 70 turns , am i right ?
     
  16. RamaD

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    About 73-74 turns. But 74 turns of 6A carrying wire, may not fit.
     
  17. mah

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    why won't it fit ? the max AWG=23.
     
  18. GopherT

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    You will be fine with 23 gauge but The last 5 or 7 turns may be double-layer on the inner circumference of the toroid.

    I don't know if you expect a constant current at 6 amps but watch for heating of the wire (and the core). Any extended time over 120 C will cause the perm of the core to drop. The epoxy binder expands / softens and allows oxygen into the core- then the iron powder starts oxidizing).
     
  19. RamaD

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    Wont #23 be too small to carry 6A?
     
  20. mah

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