Polycarbonate Encased Coils

[windygen]

I know this is a goofy question, but I'm going to ask anyway. Instead of "potting" the coils in a stator, why not encase them in a lexan "box?" For example: 3/8" thick coils with 1/16" lexan each side supported axially here and there with lots of holes for cooling. Lexan (Polycarbonate, Tuffax) is formed at temps over 300f, so in my inexperienced mind, the material should be able to tolerate the heat. The idea appeals to me because as a rookie experimenter, I would like to be able to remove/ add coils trying different configurations and wiring by simply unscrewing the top of the stator.

[SparWeb]

Hi,

I think it's been tried before.  There were several problems.  Firstly, it's not very "tough".  The lexan will crack more easily than an epoxy plate, simply because you have thinner sheets.

Nextly, about those thin sheets, how thin do they have to be to still allow the stator to fit between the rotors?  A stronger stator, with thick plastic faces, will force the two rotors apart with a wide space between.  As you read more stuff about these generators, you will discover that you get strong magnetic flux by keeping them close together.

Lastly, it's not going to be very rigid.  The individual sheets are much more flexible than a plate of epoxy the full thickness will be.  When it gets hot (and it really will!) the lexan will sag much more, scuffing on the rotors, and I've personally been there.

As a way to temporarily hold stuff together while you experiment in the shop, it's okay.  But it won't work well up on the tower, IMHO.

G'day

[windygen]

Many many thank-yous for keeping me from another goofy idea. I owe you. If I cou;d assist in your next VAWT project should you have one, I'd be happy to!

[SparWeb]

Free advice: worth every penny you paid for it.   ;^)

[TomW]

windy;

One other thing to blow holes in your idea:

The coils will be violently vibrating if not held encased "in" something as the current flow is induced in them and then stops only to go the other way on next magnets pass.

Just from here.

Be a great "test stator" rig, tho I think.

I am NOT a builder so just from reading.

Tom

[windygen]

Thanks for steering me out of this potential problem.

[TomW]

windygen;

Thanks for steering me out of this potential problem.

No problem, thats what we get paid for ;=].

lots easier to ask than to experiment only to waste resources finding out its a wash.

Tom

[vawtman]

I messed with an alternative stator for a while.It's drilled out of hdpe.Changed to a different idea.

[Capt Slog]

Just to add a different face to the story, I used polycarbonate sheet to pot my magnets.

I had thick plastic sheet laser cut to match my rotors, and the hole for the magnets were cut at the same time.  It gave very nice positioning of the mags on the rotor and I stuck the whole thing (mags to rotors to plastic) with epoxy.  I saw it as a way of saving on potting compound which was expensive and I didn't have, by replacing it with something that I had plenty of.

It's still ok, one year on.

.

[windygen]

How many coils and magnets do you have and at what point do you furl?

[Capt Slog]

I have the 'usual' 9 coils and 12 pole (dual rotor so 24 magnets).

As for the furling point, I'll admit I don't know.  It rarely gets windy enough to make it furl where I am, and it's often such a momentary event that I can't measure it.  I realise that I should be able to calculate it and have the machine furling at a known output etc.  I built in a adjustable furling, but since it's been up it appears to do what I want so I've left it alone; a case of a lucky guess and not trying to fix what isn't broke.

.

[windygen]

Thanks for the input. Sounds like you put together a really neat project.