15A pcb mount common mode choke in au

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ANyone seen a commonly available version? Checked out the usual
haunts, farnell and rs etc with no luck. Typical 250vac version as
found in SMPS's. My next attempt is Braemac or perhaps Soanar,
followed closely by constructing one myself.

Re: 15A pcb mount common mode choke in au



"The Real Andy"

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 **  Parallel two 8 amp ones.

     Farnell:   388 -5537



..........  Phil







Re: 15A pcb mount common mode choke in au


On Wed, 10 Aug 2005 20:08:46 +1000, "Phil Allison"

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Thats what I was trying to avoid :)

The design is for retired engineers (my father and his mates), so I am
trying to minimise cost and pick as much from the jaycar cat as
possible. Things are not looking to good so far from the PSU side. I
need  2 200vdc (~500uF) electros, a common mode choke, X and Y caps, a
high voltage FET. I am using the TL494, although i would prefer a
unitrode SMPS controller. Sigh....

Re: 15A pcb mount common mode choke in au



"The Real Andy"
 "Phil Allison"
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  ** Yawn.


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  **   The Farnell ones are only $5.60 each.


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 **  Ever tried making silk purses  .....



..........  Phil





Re: 15A pcb mount common mode choke in au


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Bifilar wind it yourself. Or make friends with a transformer
manufacturer, and ask nicely. At 15A its gonna want a pull-winder (giant
mechanised crochet hook)

Cheers
Terry

Re: 15A pcb mount common mode choke in au



"Terry Given"
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** I hope you are not suggesting that adjacent enamel coated wires in a coil
have the AC supply voltage between them ??

 Commercial "common mode" chokes have the two windings well separated on the
core.




.............  Phil




Re: 15A pcb mount common mode choke in au


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thats exactly what I am suggesting. triple-dipped wire, and flash
(hipot) test each unit. That'll do IEC950 etc easily (BTDT, many
thousands of times).

not a good idea (there's an understatement) with cheesy magnet wire from
Jaycar though. Good point.

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indeed. Very hard to balance them that way, leading to saturation at
high DM currents.

when bifilar wound, the inter-winding capacitance forms a balance DM T
filter. Dont get the start and finish close together though, it causes
end-to-end capacitance that bypasses the choke (DM and CM)

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Cheers
Terry

Re: 15A pcb mount common mode choke in au



"Terry Given"
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**  Then you are a dangerous LUNATIC   !!!!


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**  You cannot be sure it will not fail short in service due to
imperfections in the wire coating , corona discharge, the effects of heating
etc.



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** There is a reason -  it it so the products using them can be type
approved.




.........   Phil



Re: 15A pcb mount common mode choke in au


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along with the rest of the power electronics industry :)

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nevertheless, read the standards. Individual testing is permissible.

This is, after all, exactly what the CM choke manufacturers do. And
there are plenty of magnet wires designed specifically for this purpose.
UL listed too.

Your arguments are valid, but also apply to *every* aspect of the product.

Corona isnt much of an issue except at high E field, which usually only
occurs with very high voltages and/or very pointy things.


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mostly so they can use cheap single-dipped magnet wire.

Same reason COTS transformers have huge creepages and high leakage, vs a
triple-insulated version with full bobbin coverage of each layer (no
creepage) and low leakage.

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the core should have a suitable coating too.

Cheers
Terry the dangerous lunatic :)

Re: 15A pcb mount common mode choke in au



"Terry Given"
 Phil Allison wrote:
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  **  Speak only for yourself  -  wanker.




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**  So you now agree you are not sure.



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**  Testing is not the only issue -  as you damn well know.



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 **  You misconstrue.

There are standards for insulation thicknesses, clearances, creepages and
kinds of material *allowed* to be use where the AC supply is involved.


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** That is utter bullshit.

Corona damage affects mains voltage items -  particularly adjacent enamelled
wires.

Your lack of basic knowledge is frightening.




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 **  More utter bullshit.

  Shove your loopy Kiwi ideas where the sun don't shine.



............   Phil



Re: 15A pcb mount common mode choke in au


The Real Andy <will_get_back_to_you_on_This> wrote in

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Do you live in Melbourne by any chance, could help with most of these parts
cheap.

Re: 15A pcb mount common mode choke in au



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I am in brisbane, but i am happy to do it via post. I am at proto
stage, but may need yet need unknonw quantites.

Email: a dot pearson at tpg dot com dot au

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