Fieldlines.com || Coil Packs

Front Page - [Homebrewed Electricity-- (wind) (solar) (hydro) (steam) (controls) (storage) (mechanical)] - Classifieds - Site News
Everything - Newbies - [Remote Living-- (housing) (heat) (light) (water)] - Reviews - Diaries - Our Products

Coil Packs
By vawtman, Section Mechanical Posted on Thu Apr 26, 2007 at 09:50:05 PM MST
For the wheel

I was thinking instead of having a solid band of steel or laminates around the entire stator breaking it up into something like this

Wondering if the naturally occuring loses from the steel on a single rotor radial could be reduced.
Somtimes i wonder if neos are too powerfull for radial setups unless aircore.
Just tinkering

Coil Packs | 11 comments (11 topical)

Re: Coil Packs (3.00 / 0) (#1)
by windstuffnow on Thu Apr 26, 2007 at 05:13:57 PM MST

It will most likely cog far worse than your motor conversion ever did and the mounting bracket(s) would need to be extreemly strong. I think you'd end up with more problems than you started with... an air core might be a better way to go.

For a quick test rig you could use some thin plywood, wind some coils and simply tie strap them through some holes drilled ( or use copper wire to hold them ). Once you get it dialed in you could easily make a curved form and pour it. Instant stator section. Add sections later for more power.

.
Have Fun! Windstuff Ed

Re: Coil Packs (3.00 / 0) (#2)
by vawtman on Thu Apr 26, 2007 at 05:38:02 PM MST

Thanks Ed
Just another to put on the bad idea list.Its getting long but has room for a couple more trials.

Re: Coil Packs (3.00 / 0) (#3)
by Flux on Fri Apr 27, 2007 at 12:59:17 AM MST

"Wondering if the naturally occuring loses from the steel on a single rotor radial could be reduced.

Somtimes i wonder if neos are too powerfull for radial setups unless aircore."

Swings and roundabouts as usual. Iron loss is a function of flux density so using weaker magnets will reduce the iron loss. The price you pay is that you need more copper for the same output so you end up with much higher copper loss. With that monster thing you may well be able to get the output you want with ceramic magnets to cut the cost but you will still need to worry about the impact of iron.

With conventional (non wind)alternators, the iron loss is more than justified to reduce cost and increase output but even then the good grades of special steel are needed and proper lamination. The best compromise is when the iron and copper loss are equal at full load.

For wind where you need the lowest possible loss in low winds things change and if you keep to using iron you have to take extreme care to keep the iron loss to a minimum. If you do this by reducing flux to silly low levels then you will have a winding that is too lossy at full load to do the job. If you must use iron, stick to a motor conversion, home brew production of iron cores is impractical and foolish ( except for fun as Windstuff is doing).

Flux

[ Parent ]

Re: Coil Packs (3.00 / 0) (#4)
by Stonebrain on Fri Apr 27, 2007 at 06:18:06 AM MST

hi vawtman,

I don't agree that the steelband is a bad idea.
From my experiments with the tiny radial eddycurrentbrake,I found a significant increase in output with a can (very thin steel, <0.2mm) around.I didn't notice any
cogging,and in fact I don't expect cogging as long as the iron'core'has no teeth because attraction is uniform.Though it's important the band is a 'perfect' circle and 'perfectly' centered.
I found very low ironlosses from this configuration too.
Still have to write my complete testreport.Might be interesting for some people from the board.

Might be a good idea to try with ceramics for a big economy.A way to benefit from the plenty of place you have.

A bearing setup is something to think about too.With this heavy beast and a vertical shaft,it might be good to have a thrustbearing somewhere.Or a conical roller bearing
like many carwheel bearings.

What more should i say.
Well,go on.Your project is really interesting.

cheers,
stonebrain

Re: Coil Packs (3.00 / 0) (#5)
by vawtman on Fri Apr 27, 2007 at 06:58:43 AM MST

Stonebrain

Do you or anyone else know of suppliers of ceramic mags?

Might just save the neos for a smaller vawt im thikin about and direct drive the axial flux.

Thanks

[ Parent ]

Re: Coil Packs (3.00 / 0) (#7)
by vawtman on Fri Apr 27, 2007 at 09:53:21 AM MST

Geez, some of the prices im finding are only 50 cents cheaper for the same size mag.

[ Parent ]

Re: Coil Packs (3.00 / 0) (#9)
by Stonebrain on Fri Apr 27, 2007 at 03:19:10 PM MST

In fact,I don't know about prices of ceramics,I supposed they
were ridiculous cheap,but maybe that's only for the ceramics you
get from old speakers and microwaves.

cheers,
stonebrain

[ Parent ]

Re: Coil Packs (3.00 / 0) (#6)
by Flux on Fri Apr 27, 2007 at 08:01:59 AM MST

Perhaps I misunderstood what was intended.

"I was thinking instead of having a solid band of steel or laminates around the entire stator breaking it up into something like this"

I thought that each coil was fixed to a solid steel plate and that these were mounted in some way.

A continuous ring core will not cog. The degree of drag depends on the type of material and the method of laminating. With good material and adequate laminating it can work fine. I have built many drum type alternators this way with the magnets rotating round the outside of a smooth core ( works as well with magnets inside if you get rid of the slots).

If the coil arrangement was as I thought then it will cog and the drag will be terrible.

Flux

[ Parent ]

Re: Coil Packs (3.00 / 0) (#8)
by vawtman on Fri Apr 27, 2007 at 10:24:04 AM MST

Flux
No, you didnt misunderstand it was just another bad idea of mine.Sorry

[ Parent ]

Re: Coil Packs (3.00 / 0) (#10)
by Ungrounded Lightning Rod on Fri Apr 27, 2007 at 09:20:49 PM MST

If you want to use wire for the flux return, wind it around the whole stator in the direction of the magnet motion. The field should go through (or past) the coils, in the side of the wire, down the length of the wire to the next pole, and out the side of the wire though or past another coil. That will minimize the eddy current losses as the poles move along the wire.

This way most of your eddy currents will be a circulating current around the wire's axis as the field sinks in and pulls out, with little current down the length of the wire.

Of course good silicon-steel laminates (such as those in a motor conversion), oriented so the magnet poles "go sliding down the razor blade of life", would be better than iron wire.

Re: Coil Packs (3.00 / 0) (#11)
by vawtman on Sat Apr 28, 2007 at 10:53:59 AM MST

Thanks ulr
What do you think of using steel window screen and laminating each layer with resin to get the desired depth or height?
Would that cause eddy problems?

Just a thought

Thanks

[ Parent ]

Coil Packs | 11 comments (11 topical)

Menu

� create account
� How to use the board
� FAQs
� search the board
� Google search the board

Login

Make a new account

Username:

Password:

Total Views

��148 Scoop users have viewed this posting.

Related Links

� Also by vawtman

You must be a registered user to post here. It's easy and free, and the link is on the upper right side of your page.
All trademarks and copyrights on this page are owned by their respective companies. Postings are owned by the poster, but may be deleted or moved at the ADMIN's sole discretion. The Rest � 2009 Forcefield.
You can Email the board ADMIN here. PLEASE include the username you signed up with!