Teflon insulated magnet wire?

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Has anyone any experience with transformers wound with teflon insulated magnet wire? Polypropylene insulated magnet wire? Seems to me either of these dielectrics should render an audible improvement to a transformer (lower capacitance, lower dielectric absorptive effects). Is teflon perhaps too difficult to handle for winding purposes?
 
sightings

fdegrove said:
No....but then I have a hard time believe such magnet wire even exists...

Frank, I've researched the issue somewhat. A few wire manufacturers in the USA offer teflon enameling (not sure about polypropylene). I obtained a roll of PTFE enameled silver wire from one such manufacturer, California Fine Wire, and the enameling seems possibly sufficient for tranformer winding. The enamel is somewhat loose on the wire---slips around if you force it---is not too thick from measured specs (don't have them with me at the moment) and was hi-pot tested to 5000VDC (!). I sent an email to Tribute transformers asking their opinion on winding a transformer with this type of material. If you help me communicate with them, I'd be happy to send you some of the silver wire I had manufactured to inspect and test?

:D
 
fdegrove said:
Hi,

No....but then I have a hard time believing such magnet wire even exists...

Cheers,;) [/B]

Hi,

I’ve used Tefzel isolated wire in switch mode PSU’s for commercial purposes on recommendation of the transformer manufacturer. Due to the limited space in a small ferrite transformer it is difficult to comply with regulations for double isolation (4 kV test). The teflon isolation solved that. The wire used was 26 awg, original intended for wire-wrap purposes. Don’t think it is of use for regular 50/60 Hz mains transformers. There are other ways to obtain low coupling capacitance between primary and secondary.

If it is for audio trannies, note that the teflon isolation is rather thick. It will waste valuable space in such a trannie (low fill factor). The result is higher copper resistance.

Cheers ;)
 
diyAudio Senior Member
Joined 2002
Hi,

If it is for audio trannies, note that the teflon isolation is rather thick. It will waste valuable space in such a trannie (low fill factor). The result is higher copper resistance.

That's indeed the major concern if the insulation is regular PTFE as in Tefzel wire.
However if it has the insulation thickness of a coating such as normal enamel then we're talking. :)

I know AudioNote prefers polyurethane over polyimide (ML?) for both the OPTS and their range of hook-up wire for sonic reasons but maybe they're as unaware of the existence of PTFE enamels as I am.:D

Cheers,;)
 
Disabled Account
Joined 2004
Steve Eddy said:
Cooner Wire sells Teflon enameled wire (quad build) in a variety of gauges and metals. I priced their 30 gauge copper with Teflon (because of the enameling process, the copper doesn't have to be tin or silver plated) and they want $2.75 a foot for 100 feet.

http://www.coonerwire.com/Products/MEW.tml

se

Still at it Steve?
I'm still kicking!

Ken A
 
fdegrove said:
Although I find it easy to tell polyestercaps, polycarbonate, polypropylene and polystyrenes apart, I really would be hard pressed to describe the sound of teflon...

Any takers ?


Not sure I can hit but one or two of the more salient aspects of teflon sound, but adjectives like smooth and buttery come to mind, combined with a hint of glare. The sound of teflon seems to me particularly evident in very low (almost as if to boost) and high frequencies. Comparing teflon to other plastic dielectrics, I find an teflon to produce a lower level of sonic irritation of the sort I associate with polystyrene, polypropylene and especially mylar (polyester). The distortions of any of these capacitors, to my ears, are quite unlike THD or even high order harmonic distortion, and impart, to my limited descriptive abilities, an overall flavour or sense to the music, like hardness and low-level veiling. I also suspect capacitor distortions eliminate musical information to some degree.

I'll phone California Fine Wire tomorrow and inquire about enamel thicknesses and whether the company also offers polypropylene enamel. Re their teflon product, I suspect they can enamel wire in various enamel thicknesses, as the wire I purchased (the enamel on which seems very thin) was tested to 5,000VDC (in other words, a little beyond the call of duty). They also can enamel square wire, which wire might reduce winding volume.
 
Steve Eddy said:
Cooner Wire sells Teflon enameled wire (quad build) in a variety of gauges and metals. I priced their 30 gauge copper with Teflon (because of the enameling process, the copper doesn't have to be tin or silver plated) and they want $2.75 a foot for 100 feet.

Hi Steve,

For comparison, California Fine Wire sold me 24 guage teflon enameled 99.99% silver for just over $1 a foot.

Tom
 
Kapton - Polyimide Wire

Polyimide (DuPont Kapton) coated wire is very common for high power speaker voice coils and transformers. Polyimide can handle temperatures over 400C before melting. Polyimide adheres very well to properly prepared copper, and is durable enough to run through a transformer winding machine.
 
serengetiplains said:
For comparison, California Fine Wire sold me 24 guage teflon enameled 99.99% silver for just over $1 a foot.

Thanks, Tom!

I rather thought Cooner's prices were on the high side. Though what sort of build is on the wire you got? It may be that it was only a single or double build which could explain the price difference. The stuff Cooner's selling is a quad build, so that means two more runs through the process compared to a double build.

se
 
Re: Kapton - Polyimide Wire

LineSource said:
Polyimide (DuPont Kapton) coated wire is very common for high power speaker voice coils and transformers. Polyimide can handle temperatures over 400C before melting. Polyimide adheres very well to properly prepared copper, and is durable enough to run through a transformer winding machine.

Though it does have to be chemically or mechanially stripped. Not so bad for businesses who have the proper equipment, not so good for the DIYer.

se
 
Kapton

LineSource said:
Polyimide (DuPont Kapton) coated wire is very common for high power speaker voice coils and transformers. Polyimide can handle temperatures over 400C before melting. Polyimide adheres very well to properly prepared copper, and is durable enough to run through a transformer winding machine.

Good thought, Paul, but kapton doesn't quite make the grade. Several years ago at a time I was inquiring about the best capacitor available for signal transmission, I spoke with the head engineer at Component Research Corp about the possibility of using kapton as a capacitor dielectric. Kapton, I then had recently discovered, has a very high dielectric breakdown voltage --- higher than teflon. I previously had purchased some teflon capacitors from CRC and wondered if kapton might produce a better variety. The CRC engineer told me kapton is a poor dielectric considered from the vantage point of kapton's high dielectric losses and dielectric absorption. I then asked him if he knew of a better dielectric than teflon. His answer was an unequivocal no. CRC, to be clear, manufactures high end military and aerospace use capacitors. They've even developed a process by which they metallise teflon (!) to create a smaller teflon capacitor (evidently to capture teflon's high quality for a greater number of uses). I've purchased some of these metallised teflon capacitors and they sound excellent and still do. All of which is to say CRC probably knows their stuff so far as teflon is concerned.
 
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