insulation type

[NightWinder]

LOL....Class Ahhh. Possum, your just insanely cool!! : )

[Possum]

cool.....

guys print this thread out and file it away somewhere, this was a good one......

[Possum]

a test....

don't have time to do this but a good test for you guys with the Extechs should wind a strat pickup to 7K with poly then one with PE and see if they do what we talked about here, wish I had time to do it.

[DrStrangelove]

UL insulation class

... Plain enamel is described as Class A as are formvar and the poly wires. Epoxy and polyester are described as class B and teflon as class H. ... What is the class system referring to anyway A/B/H ?

It's the heat range if Google is to be believed.
A search turns up Underwriters Lab insulation class with numbers like:

Y 90 °C
A 105 °C
E 120 °C
B 130 °C
F 155 °C
H 180 °C
N 200 °C
R 220 °C
S 250 °C

It has been superceded by the NEMA-1000 specs you see on MWS and the rest.

Teflon is desicrbed as having excellent dielectric properties, so maybe plain enamel is the same as formvar and poly?

Teflon is a poor capacitor dielectric (2.0) but is unusually stable over changes in power and temperature, and has extremely low loss (<.09%) of applied AC signal. Polyester and ceramic caps are also microphonic while teflon, which is mechanically soft and self damping, is not.

Some insulations are also piezoelectric -- they move when you give them a voltage and vice versa. For example, Kynar insulation is tough stuff and, although unsuitable for magnet wire, is great for piezoelectric pickups.

The point is that some insulations contribute to microphonics more than others and make you want to pot the pickup.

-drh

[Mark Hammer]

Haven't got time to read through all the posts in this thread, but I'm wondering about the extent to which the various insulations are uniform in their thickness, as a result of their viscosity and tendency to shrink or clump during drying. That is, is one of them more inconsistent in its thickness along its length? I would think that could have effects tantamount to "scatter".

Or am I out to lunch?

[David Schwab]

All I can find on plain enamel calls it oleoresinous enamel or yellow varnish.

That would be it then... spar (marine) varnish. You see a lot of old electrical things coated in varnish. I'm guessing that was one of the first insulators used.

Interestingly, olioresin is made from organic plant compounds. When used in varnish it's usually made from Canada Balsam.

You don't have to bake it, but I can't imagine wire makers letting it air cure either.

Might be a good stuff to pot pickups in.

Nitrocellulose was originally made from cotton. So maybe when people say something sounds "organic" they are being literal!


Also, oleoresin capsicum is the proper name for pepper spray!

I'll certainly try. A dielectric is an insulator for direct current but it often passes AC. The AC qualities of interest are dielectric constant and dielectric absorption (loss factor). Low dielectric constant (d.c.)means it's a poor capacitor, like air ( = 1.0) while a higher number means it passes AC better.

For anyone reading that hasn't seen the connection yet... a capacitor is two conductors separated by an insulator. The insulator blocks DC, but passes AC at varying frequencies depending on the value of the cap. The higher the capacitance, lower the frequencies it passes.

So now we can see how different insulations would change the capacitance of the coil.

This is getting interesting!

[David Schwab]

Some insulations are also piezoelectric -- they move when you give them a voltage and vice versa. For example, Kynar insulation is tough stuff and, although unsuitable for magnet wire, is great for piezoelectric pickups.

The point is that some insulations contribute to microphonics more than others and make you want to pot the pickup.

Then you have the triboelectric effect, which can create noise in cables. But not in a good way like piezo coax cable.

[DrStrangelove]

a little perspective

That would be it then... spar (marine) varnish. You see a lot of old electrical things coated in varnish. I'm guessing that was one of the first insulators used.

Rather, it is called all of the following:
plain enamel, oleoresin enamel, yellow varnish, and spar varnish.

There are probably a few more synonyms out there.

Interestingly, olioresin is made from organic plant compounds. When used in varnish it's usually made from Canada Balsam.

Oleoresin is an old pharmacological term.
It means is that there is a resin in an oil solution or suspension.

You don't have to bake it, but I can't imagine wire makers letting it air cure either.

That's why they have short and long oil varnishes for baked vs. air cures.

Might be a good stuff to pot pickups in.

It might dissolve PE insulation while it cured, too.

Nitrocellulose was originally made from cotton. So maybe when people say something sounds "organic" they are being literal!

Nitric acid (crucial in making nitrocellulose) originally came from treating the nitrates in cow manure (or political speeches) with concentrated sulfuric acid got from heating alum+iron sulfate (al-Jabir's method). It was possible to make nitrocellulose in 9th century Persia, but I digress.

So now we can see how different insulations would change the capacitance of the coil.

This is getting interesting!

Lordy, do you know how many years it's taken to get the cause of distributed capacitance into the discussion here?! Until now, it was always about what and never the why of it.

You folks are going to shit when we dig into mutual inductive coupling of adjacent windings -- it's at the heart of why scatterwinds sound so much better.

-drh