Foam Insulated Wire

You may be looking in the wrong place. The first item in the Farnell catalogue of coxial cables is RG6/U 75R coax with a foamed polyethylene dielectric. Foamed PTFE seems to be too exotic for them, but more specialist suppliers seem to carry it.

-- Bill Sloman, Nijmegen

Foam dielectric is evil stuff. With a bit of mechanical load and temperature swings, the conductor eventually migrates through the foam, which is bad news. You're probably better off using space-wound magnet wire.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net

I suspect you want Litz wire for that application at that frequency. Litz wire made of many thin strands, insulated from each other, is available in many composite gauges and insulation types. Foam is not one of them. You can make your own Litz wire by paralleling and filar winding a number of thin insulated magnet wires to make up any gauge desired.

Why?

John

You believe in foam insulated wire even though you can't find any evidence of it? I suppose you also believe your lunchbox is orbiting Mars?

:-)

RogerN

..but of course; Elvis has it and he is there..

It's an effort to reduce distributed capacitance (capacitance between windings) on a planar core to lower EMI and powersemi heating.

The difference is.... Without evidence, I can reject and forget about foam insulated wire at any time.. Christians don't use the absence of evidence to reject God.

If you feel there's something more to reality, well, that's just your survival instinct talking to you. Sometimes an imaginary tiger in the bush can keep you safe. It's old monkey behavior still lingering in monkey based brains. And nobody can disprove it so it must be true. And nobody can disprove my lunchbox is orbiting Mars...so it must be true.

Ah risky...

Elvis is complaining that DofBC didn't pack a peanutbutter nanner sandwich in it.

RogerN

That's where you get it wrong, you incorrectly assume Christianity is based on lack of evidence. It is based on faith in evidence though, that's not the same as blind faith. There are many Christians that at one time were Atheists, just like you, and thought there was no evidence for Christianity, just like you, but they researched it, unlike you, and became believers.

Theological seminaries are infected with liberal indoctrinators (as opposed to educators) that cast doubt at everything they don't like. Many get weeded out by these false teachers, others overcome them and see their false teaching for what it is. BS such as Isaiah wasn't written by Isaiah, it was written by another man named Isaiah that lived back they, yeah right, whatever. Jon Kirwan tried to take me down the road of who wrote what, but like I told him, I don't care if Kermit the frog wrote it, what maters for prophecy is that it was written before the event and then fulfilled. Educated idiot criticisms don't mean squat to me. The very book in question was found in the dead sea scrolls and dated before the fulfillment, proving the scholarly critics for the false teachers they are. These false teachers are able because they can make up any crap they want and it's hard to disprove it about events that happened thousands of years ago.

RogerN

I don't think that going to a foam coated wire is going to help you enough to matter. To reduce the stray capacitance, I have made and inductor using a coil former with multiple bays. By breaking the winding into three sections, you get a significant reduction in the capacitance between layers.

You can also make your inductor out of two inductors in series. The SRF values can be made not to line up by making the values a little different.

Faith in evidence for God?? wtf does that mean? I suspect ignoratio elenchi being used.

Faith (as per websters dictionary) means believing without the evidence. Hopefully your using the agreed upon language meaning for the word faith. You got no evidence for God so now you have to have faith in evidence for God? Yikes that's really at the bottom of the barrel. Example: I have faith there's evidence for leprechauns.

Or perhaps you mean that you have faith that perhaps somebody will find evidence someday for God. Perhaps an indestructible monolith will be found that has a mysterious inscription on it that is read by all languages (psychic print) to mean 'Your planet rent is due in 2012'.

What did they research? Of Pandas and People?

Ridiculous..

I don't debate scripture because an expertise in dead languages is not practical to me. That area is a mess that could have been created by desert monkeys on magic mushrooms.. I use science for electronics and science (including psychology) is what I'll use to debunk supernatural stuff. Consider the picture that your God is painting for you:

God's persuasion skills suck in a trick universe that looks massively old and a trick biology that looks massively slow to evolve.

If you've given up on printed windings, you might consider giving up on the planar core shape as well. These strays are intended to be integrated into the topology, with fairly controlled tolerances.

Without alteration of core shape, the reduction limits of interwinding capacitance should be a math excercise. You want air; insert an 'airy' spacer.

RL

I guess if you want it bad enough you can take apart some foam coax...

huh..I didn't think of that. Maybe I might find coax with foam dielectric that's less than 1mm in diameter.

I like the convience of winding insulated wire on the core for smps prototypes.

I considered spacers with wire. I might try glueing pieces of insulation to magnet wire to act as spacers.

Beware that when winding transformers (obviously, not a single inductor :-) space between windings is leakage inductance.

Your foamed wire is trading capacitance for leakage inductance. Surely not a great thing at 1MHz.

Of course the same applies for bare 'no former' windings.

--
Thanks,
Fred.

Faith in evidence for God?? wtf does that mean? I suspect ignoratio elenchi being used.

Faith (as per websters dictionary) means believing without the evidence. Hopefully your using the agreed upon language meaning for the word faith. You got no evidence for God so now you have to have faith in evidence for God? Yikes that's really at the bottom of the barrel. Example: I have faith there's evidence for leprechauns.

Or perhaps you mean that you have faith that perhaps somebody will find evidence someday for God. Perhaps an indestructible monolith will be found that has a mysterious inscription on it that is read by all languages (psychic print) to mean 'Your planet rent is due in 2012'.

What did they research? Of Pandas and People?

Ridiculous..

I don't debate scripture because an expertise in dead languages is not practical to me. That area is a mess that could have been created by desert monkeys on magic mushrooms.. I use science for electronics and science (including psychology) is what I'll use to debunk supernatural stuff. Consider the picture that your God is painting for you:

God's persuasion skills suck in a trick universe that looks massively old and a trick biology that looks massively slow to evolve.