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Old 7th March 2013, 12:48 PM   #101
popilin is offline popilin  Argentina
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Quote:
Originally Posted by esltransformer View Post
Normal commercial available nomex has not a very low dielectical constance as far a a know. Mostly it's between 3.5 and 4.5. Nomex is available in many different qualities and the harder its pressed the higher the ε is. It can be up till 8! There is a quality unpressed nomex with a ε=1.3 however this is not standard available. If anybody knows a suplier please send me a pm.
http://www.osdasrl.com.ar/pdf/tec410.pdf
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Old 7th March 2013, 12:55 PM   #102
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i would like to have nomex 411
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Old 7th March 2013, 01:02 PM   #103
popilin is offline popilin  Argentina
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Originally Posted by esltransformer View Post
i would like to have nomex 411
Even better, ε = 1.3 @ 1KHz

http://www2.dupont.com/Energy_Soluti...nloads/411.pdf
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Old 7th March 2013, 01:07 PM   #104
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Originally Posted by popilin View Post
I know it is better but who sells it and what are the costs?

I know many nomex surpliers sell laminated nomex ( mylar or kapton). These nomex are worse.

very good is also paper ε=2
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Old 7th March 2013, 01:12 PM   #105
JMFahey is offline JMFahey  Argentina
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I used to buy at "Electro aislante" in Buenos Aires, they had a shop at Av. San Juan but then moved to Av Entre Ríos.
Only problem is they are real *Industry* suppliers and demand a commercial CUIT (Argentine IRS Company ID number) to sell to you.
Get a friend to "lend" you their number.
My IRSA wholesale wire supplier also has some Nomex thicknesses available, you can buy "black" (no papers) from him:
ABRAHIM EMILIO ALAMBRE DE COBRE ESMALTADOS
CHILE 639, 1098 BUENOS AIRES | Teléfono : (011) 436 163 66
Not that much problem with papers, if you pay cash, but they heve no In ternet page, you must go there "in person" and see what they have available.
They fear robbery , so you will have to call them, make them trust you, and probably talk a lot through a 2" hole in their bullet proof door before they open it.
And even so, they may not sell you at all.
Tell them "Fahey de La Boca" is your friend and told you to buy there.
And even so they may ring me to check I know you, so send me a mail a few days before, just in case.
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Old 7th March 2013, 01:17 PM   #106
popilin is offline popilin  Argentina
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Quote:
Originally Posted by esltransformer View Post
I know it is better but who sells it and what are the costs?

I know many nomex surpliers sell laminated nomex ( mylar or kapton). These nomex are worse.

very good is also paper ε=2
Sorry, I do not sell NOMEX and my provider is a "Kiosk" seedy, in Córdoba city.

NOMEX 410 is something like laminated, is "calendered"

Paper is good dry, what about varnish or moisture ?
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Last edited by popilin; 7th March 2013 at 01:27 PM. Reason: Tarzan-English
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Old 7th March 2013, 04:03 PM   #107
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I would think in order to get dielectric constants approaching 1 you need a very porous material (mostly air). In lieu of the expensive materials such as expanded teflon and nomex why not just use a glass cloth electrical tape (thermosetting or apply a thin layer of uralane to the cloth) ?

There used to be at least one chemical stripper for the poyimide wire (worked great) but given its health and environmental concerns I would strongly avoid it (now wish I had as well).

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-Antonio
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Old 7th March 2013, 04:10 PM   #108
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If it doesn't occupy too much winding window (space at bobbin), you can try it.
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Old 7th March 2013, 04:35 PM   #109
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I have, many times. My experiences are for very different applications hence different goals and constraints, just figured its worth putting out there.

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-Antonio
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Old 7th March 2013, 05:05 PM   #110
popilin is offline popilin  Argentina
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Quote:
Originally Posted by magnoman View Post
I would think in order to get dielectric constants approaching 1 you need a very porous material (mostly air). In lieu of the expensive materials such as expanded teflon and nomex why not just use a glass cloth electrical tape (thermosetting or apply a thin layer of uralane to the cloth) ?
Because through the pores, you lose insulation, moist air has a breakdown voltage of about 900 V.

Glass ε > 4 , uralane has a dielectric constant similar to Teflon, so the mix isn't a good deal.

Quote:
Originally Posted by magnoman View Post
There used to be at least one chemical stripper for the poyimide wire (worked great) but given its health and environmental concerns I would strongly avoid it (now wish I had as well).

Thanks
-Antonio
Tell me, please, I will use a mask.
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