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Experimental Windings
By WXYZCIENCE, Section Mechanical Posted on Sun Oct 8th, 2006 at 02:52:49 AM MST
Can radial have a place in the Air Core

I was experimenting with this radial winding design. Has anyone ever tried this type of air core for a radial design?

I was getting 11volts from this wave test wind with a twelve pole magnet stator. I also skewed the winding which only reduced the output. The air gap was large, so closer air gap would improve the output. This is one phase, typically other configuration could be suggested. Any comments welcome.

Joseph

Experimental Windings | 45 comments (45 topical, 0 editorial)

Re: Experimental Windings (3.00 / 0) (#1)
by stephent on Sat Oct 7th, 2006 at 09:06:30 PM MST
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What's the size of the tube?
And what's the mag rotor size, shape etc?
Looks interesting--mo' info!!

Re: Experimental Windings (3.00 / 0) (#2)
by WXYZCIENCE on Sat Oct 7th, 2006 at 09:19:15 PM MST
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stephent, the tube is 4" in diameter and 6" in length made from fiberglass. The wire was stripped from an old transformer (#24 ?) The stator was from my motor conversion pictured here.

Joseph.

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#7)
by johnnythefox (johnnythefox#sbcglobal.net) on Sat Oct 7th, 2006 at 10:37:10 PM MST
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I've had simular thought's along these lines.
With a little more outside the box thinking you could set the shaft as stationary and let the mags rotate on the outside of your coils inside of a piece of pipe on bairrings.
This would force the mags out against the pipe no chance of them coming lose.
good luck
have fun
johnnythefox

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#8)
by johnnythefox (johnnythefox#sbcglobal.net) on Sat Oct 7th, 2006 at 10:43:26 PM MST
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Well you would also need to drill out the shaft too allow the egress of the wires from the coils.
Johnnythefox

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#3)
by zubbly on Sat Oct 7th, 2006 at 09:26:46 PM MST
(User Info) www.zubbly.com

hey WXYZCIENCE,

that has to be one of coolest examples of thinking i have seen here in quite a while.
i think your idea has a huge potential of developing into a great genny.

looks plenty easy to do and am sure others will help develop your new idea.

great work!
zubbly

Re: Experimental Windings (3.00 / 0) (#4)
by stephent on Sat Oct 7th, 2006 at 10:01:32 PM MST
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Should work as well as any single mag plate without laminates.
And it could be easy to put some laminates into the picture too.
Only thing I see could be that the wire ends sticking into the center could limit the air gap a bit (clearance with rotor going into the stator at assembly).
Couple of tabs to wind one end of the coils around instead of the loop inside could fix that....it has possibilities.
Keep developing and thinking....that's how good discoveries are made. And it helps keep me from trying stuff when y'all do it and find it doesn't work well.....I'm making my "to try" list longer every day now.
Geeeezz--now if I can make it to living to 120 years old or so--and y'all don't keep coming up with interesting ideas to try--I'll have it made.

Re: Experimental Windings (3.00 / 0) (#10)
by WXYZCIENCE on Sun Oct 8th, 2006 at 12:08:00 AM MST
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stephent, the rotor (that I have been calling the stator) easily cleared the wires on the ends. I figured, coils could be wound on a form and the fixed to the tube and cast in place. This would allow for less airspace.

Joseph.

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#5)
by Countryboy on Sat Oct 7th, 2006 at 10:24:15 PM MST
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Why did you skew the windings?

The copper windings don't attract the magnetic flux, so they have zero affect on cogging. Cogging is caused by the magnets 'sticking' more to the iron backing in some portions of the rotation than others.

Did you use any iron backing on the outside of the stator windings to attract flux? That would greatly help voltage output if you did that.

What material is the coil holder made out of?

It's definately an interesting approach.

Re: Experimental Windings (3.00 / 0) (#6)
by Countryboy on Sat Oct 7th, 2006 at 10:25:02 PM MST
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I almost forgot. What RPM did you get the 11 volts at?

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#9)
by WXYZCIENCE on Sat Oct 7th, 2006 at 11:49:39 PM MST
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Countryboy, the tube is made from fiberglass. I skewed the wires just to see what would happen. You are right about the zero cogging. There was lots of coil vibration because the coils were not held tight. I tested the unit at 600 rpms.

Some of my ideas that could be tried:

Increase the diameter to 12" x 3.14 = 37.68" of coil space

Increase the length to 12'' would give twice the output.

Also I think heat would be dissipated easier.
Bearings spaced 14" apart could take loads created from gyro forces.

Joseph.

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#11)
by Flux on Sun Oct 8th, 2006 at 12:47:47 AM MST
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Yes of course you can make any radial form of the axial machine.

Axial construction is simpler for those with no machining facilities. If you have the facilities to control the air gap the radial has some advantages. The winding is constant width and it is easy to use the overlapped coil method without running out of space at the centre.

In the simple form that you have tried, it is wasteful of material just in the same way as the single rotor axial. You can make it dual rotor by having another drum of magnets outside. It then becomes a bit of a challenge to support the stator but it can be done.

You can keep the magnet drum on the outside and use laminates to wind your coils on. It then becomes the equivalent of the single rotor with laminated core but has the big advantage that cores are readily obtainable. Just use motor cores and ignore the teeth on the inside. Unlike its axial equivalent this form does not suffer from the large magnetic attraction force loading the bearings.
Flux

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#20)
by WXYZCIENCE on Sun Oct 8th, 2006 at 11:08:36 AM MST
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Flux, removing the weight was one of my reasons for thinking of this design. I could maintain the twelve pole design and simply increase the length, in this was use more, smaller less expensive magnets. Cooling would then be relative to the surface area of the external stator. This would also help counter inadequate magnet thickness.

The tube can be made without machining by wrapping cardboard around the rotor to the desired thickness, then glass cloth and resin.

Joseph.

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#12)
by Warrior on Sun Oct 8th, 2006 at 01:04:56 AM MST
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I believe that Southwest Windpower uses this in their new Skystream turbine.

It has a slotless 42 pole radial flux alternator to harvest low winds. I suppose they don't have any laminations or iron in the alternator.

The alternator bore is quite large, about 14".

Check my files and look for Skystream, the file has info on their protype

Warrior
Warrior__ "Why can't Murphy's Law be used to my advantage??"
[ Parent ]

Re: Experimental Windings (3.00 / 0) (#13)
by Flux on Sun Oct 8th, 2006 at 01:48:53 AM MST
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It probably does have iron but no slots. It is probably similar to Hugh's brake drum alternator.

If you make it without iron then it becomes much more difficult to cool and uses more magnets.

With a laminated iron core with no slots the iron loss is low, cogging non existent, construction is much easier than a self supporting ironless stator and cooling is very much better directly on to the iron core.

As a commercial proposition where cost is an issue I suspect they use iron.
Flux

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#14)
by electrondady1 on Sun Oct 8th, 2006 at 06:46:27 AM MST
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i've thought about this configuration as well this is as far as ive gotten so far

the most tempting aspect is the percentage of end to leg lengh.

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#15)
by Flux on Sun Oct 8th, 2006 at 07:07:34 AM MST
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Yes the dual rotor version should work fine.
Flux

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#16)
by tecker on Sun Oct 8th, 2006 at 08:34:03 AM MST
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You'll need another mag set on the other side to get an effective chage division of the coil and the null point of the field will have to be in middle somewhere so a thicker winding cylinder is in order . You could wind the inside over one pole and the outside over the ajacent poll and a steel cylinder aroung the outside ,

Re: Experimental Windings (3.00 / 0) (#17)
by tecker on Sun Oct 8th, 2006 at 08:37:32 AM MST
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Sorry once again the pic was too small to get the scope of what you were suggesting ignore all but the steel cylinder part

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#18)
by DanG on Sun Oct 8th, 2006 at 09:50:44 AM MST
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All the makings of a switched reluctance motor / generator...

Here is a Maytag tossed due to failed controller I puttered w/ a while back.

I was wondering how to reuse the bearing and armature - looks like some PVC pipe to replace the laminate section with is in my future...

http://www.fieldlines.com/story/2005/7/14/42640/9511

Re: Experimental Windings (3.00 / 0) (#19)
by tecker on Sun Oct 8th, 2006 at 10:03:46 AM MST
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Yes I loked into doing same with an auto alternator more copper less cog.

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#21)
by WXYZCIENCE on Sun Oct 8th, 2006 at 11:25:30 AM MST
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DanG, I looked over your post, I will be interested in how the pvc pipe idea works out. Have you tried wrapping the rotor with cardboard and use iron filings to see how the flux lines run.

Joseph

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#22)
by richhagen (richhagen (a t) Juno.com) on Sun Oct 8th, 2006 at 12:34:25 PM MST
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I like the stator you made. It looks to me like you started to make it three phase based on the blue and green markings in the photo. (probably were little red marks to start where the notches are now :-) It looks to me like placing an outer drum with magnets of appropriate placement and magnetic polarity lining the inside of it would be the equivelant of a dual rotor axial flux folded over. Then you could mount the stator with the wires egressing from the back and end up with a pretty neat machine. I've seen commercial radial flux machines with the magnets lining the inside of an outer drum with a laminate stack wrapped with copper for the stator on the inside. But with a rotor in the center and an air core design, cogging should be minimal, yielding a better low wind machine. Rich
'A Joule saved is a Joule made'

Re: Experimental Windings (3.00 / 0) (#23)
by americanreman on Sun Oct 8th, 2006 at 06:06:55 PM MST
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I did this same thing with some pvc pipe but I hot glued the coils to the outside, it was thin wall drainage pipe with holes in it.

Then used steel pipe for the rotor with rectangle magnets, had the guy at home depot cut me a piece and thread both ends so I could screw caps on to the ends with holes drilled on center for the shaft (still have to work on a jig to get the holes drilled on center a bit better), mounted the magnets and built a wood block bearing system just for testing...worked pretty good hooked to drill at about 650 rpm.

It was intended for a small vawt or 2 for my boat.

Didn't get past that point and I'm looking at it right now sitting in the corner of my office...thanks for the inspiration to tinker with it this week!

Re: Experimental Windings (3.00 / 0) (#24)
by WXYZCIENCE on Sun Oct 8th, 2006 at 07:13:57 PM MST
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Americanreman, can you post some pics of the unit. I thought about using 4" abs plastic and cutting grooves into it with my radial indexer then build up some end caps to support the rotor. Anyway I will be working on something along that line this month. Lots of winter projects for me.

Joseph.

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#25)
by americanreman on Mon Oct 9th, 2006 at 06:05:21 AM MST
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My camera's on the fritz but I'll see if the ole lady will bring hers home from work.

Another thing I have looked at doing is making halves of the pvc pipe so you can easily place the coils inside the pipe then put the 2 halves back together and use male pvc end caps with a few screws to hold it all together.

Here's the cool part, I used cat 5 lan wire for the coils ;0) - 4 wraps of twisted pair 8 lead tightly held together, you can wire it several different ways for amps or voltage.

I haven't played around with it much lately because of time constraints, I was wanting to make a small farm of these for my boat for pathway lights, etc. I'm not looking for alot of power or time and money spent, something that can be built in a few hours from easily available materials and doesn't need bearings, small shaft riding in a pvc hole in the end cap, when it gets a little sloppy just replace the end caps for a few bucks. It has to look good and be safe so not to damage my boat or another boat nearby should something go flying off...

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#26)
by tecker on Mon Oct 9th, 2006 at 07:37:08 AM MST
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Just a side note .A rollerblade bearing fits reallygood in a 3/4 coupling or reducer etc .

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#27)
by WXYZCIENCE on Mon Oct 9th, 2006 at 11:25:34 AM MST
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Your bearing idea should work good. All kinds of plastic bearings are used and actually outlive bronze or steel. The forces of this kind of bearing would also be low. I have some nylatron bearings from deep well pumps that have had tewnty years with hard service on them.

A molded plastic windmill? Light, cheap, weather resistant. Should work good.

Joseph.

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#28)
by americanreman on Mon Oct 9th, 2006 at 12:03:20 PM MST
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Yep, might even wear the steel and not the pvc, time would only tell.

If you ever had a rack & pinion steering gm car in the late 80's to early 90's and it would only assist in one direction usually to the right...gm learned the hard way the teflon is harder than the metals used in building the rack, teflon wore grooves in the aluminum and even the steel sleeves they used to repair the bores on the rebuilt units for example. They obviously thought it would be the other way around.

[ Parent ]

Re: 18 pole design (3.00 / 0) (#29)
by WXYZCIENCE on Mon Oct 9th, 2006 at 03:08:33 PM MST
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This is a diagram of the first RACA, (Radial Air Core Alternator) an eighteen pole single phase alternator.

70 turns per coil, nine coils.

The stator will be cut from a 5" plastic tube.

18 - 2"x.5"x.38' N40 Neo magnets.

Input welcome, Joseph.

Re: Experimental Windings (3.00 / 0) (#30)
by powerbuoy on Mon Oct 9th, 2006 at 06:43:02 PM MST
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Great idea, but: I believe that you will not have an advantage with the drum design as long as the magnets are on the inside only. It would make more sense once you put magnets on the in AND the out side. But now you enter a hole new ballgame of complications and design issues.
Every three phase laminated motor is a drum design which works well thanks to the laminated stator. Its drawback maybe cogging but you'll have more advantages because of an existing stator, endbells and existing (to be modified) rotor you can work with. In my opinion you would be better of with a motor conversion.

Powerbuoy

Re: Experimental Windings (3.00 / 0) (#31)
by WXYZCIENCE on Mon Oct 9th, 2006 at 11:08:27 PM MST
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Thanks for the input Powerbouy. Building it will be the best part. I can add an outer ring later. My motor conversion (Zubbly design) was fun to build and it works wonderfully.

Joseph.

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#32)
by electrondady1 on Tue Oct 10th, 2006 at 08:38:18 AM MST
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wxyzcience,(joseph)
very interested in the devise you are planing
for slow turning generators i think the radial design has real promise.
with very long poles the percentage of active copper in a coil is increased.
it would seem there is little limit as to the volume of magnet
that could be put in place.
hope you keep us informed.

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#33)
by hvirtane (hannu_markus_virtanen(at)yahoo(dot)com) on Tue Oct 10th, 2006 at 10:06:46 AM MST
(User Info) http://web.archive.org/web/20050404022706/www.cc.jyu.fi/~hvirtane/cooker/

Hi,

I've been thinking about the same design, but not done anything for it[:=(].

I agree with this note:

"With very long poles the percentage of active copper in a coil is increased. It would seem there is little limit as to the volume of magnet that could be put in place."

I think that it is workable with very little tools, if steel pipes would be used for magnet rotors. If making with a single magnet rotor design, could (plastic covered) iron wire be used as stator irons?

- Hannu

Re: Experimental Windings (3.00 / 0) (#34)
by powerbuoy on Tue Oct 10th, 2006 at 10:14:15 AM MST
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That is actually some idea ... imagine a 3 foot long stator tube ...

powerbuoy

Re: Experimental Windings (3.00 / 0) (#35)
by WXYZCIENCE on Tue Oct 10th, 2006 at 11:26:46 AM MST
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Powerbouy, my test model should give me the figures on watts per inch. From these numbers I will be able to get workable data. Another idea was to build one 6' long and use the stator as an integral center support for a vawt.

Joseph.

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#36)
by powerbuoy on Tue Oct 10th, 2006 at 07:31:16 PM MST
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Keep us updated on your progress, would be nice to see one day an experimental "tube" ...

Re: Experimental Windings (3.00 / 0) (#37)
by tecker on Wed Oct 11th, 2006 at 03:00:08 AM MST
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I'm going to try this in a test setup .I fear without some kind of flux direction the voltage will be slight .Wave form very short duration . The coil end needs to go to the outside so the rotor will clear.Its cool though because you can wind one phase with no interconnects .( shoot a loop throu the tube and hook it cut slots in the tube at different depts for each phase

Re: Experimental Windings (3.00 / 0) (#38)
by hvirtane (hannu_markus_virtanen(at)yahoo(dot)com) on Wed Oct 11th, 2006 at 03:18:13 AM MST
(User Info) http://web.archive.org/web/20050404022706/www.cc.jyu.fi/~hvirtane/cooker/

Are you going to make it with one magnet rotor or with two magnet rotors?

- Hannu

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#41)
by electrondady1 on Wed Oct 11th, 2006 at 10:04:13 AM MST
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this idea surfaces every so often .

i think the layout would have some real advantages.
but i don't recall any posts were a successful devise has been created.

to build a dual rotor or single rotor radial generator would require very accurate pieces.
it is difficult enough (for me) to get two steel disks to rotate in parallel ,
add to that two steel pipes of whatever lengh attached to the disks.

any imperfection present will be multiplied by the lengh of the rotors .

now a cylinder (stator) must be inserted into the cavity and held in place perfectly.

without a lathe of my own or a machinest willing to work for nothing it would be a very expensive experiment.

i suggest hannu should spy on windside turbines there in finland. from the size and shape of the generator section of thier windmills i suspect they are using a radial design
careful hannu , don't get arrested !! lol

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#43)
by hvirtane (hannu_markus_virtanen(at)yahoo(dot)com) on Wed Oct 11th, 2006 at 11:25:38 AM MST
(User Info) http://web.archive.org/web/20050404022706/www.cc.jyu.fi/~hvirtane/cooker/

"...on windside turbines there in finland.
from the size and shape of the generator
section of their windmills
i suspect they are using
a radial design..."

I know quite well the people from Windside
and have visited their factory
a couple of times.

I've never opened their generators, however,
but I think that their generators
are converted induction engines.
I think that the rotor is
done according to the principle
as shown on my following picture:

In this idea the magnets are
rectangular pieces and
the axle is made of stainless,
nonmagnetic steel.
An advantage is that you don't need
to worry about nonobtainable curved magnets
and anyway will get a small air gap.

You might be right that it is
more difficult to make radial
flux generator parts
than axial flux generator parts,
if you don't have an access to any lathe...

- Hannu

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#44)
by spinner (itsmejonny@email2me.net) on Wed Oct 25th, 2006 at 08:34:02 AM MST
(User Info)

their units have always intrigued me, they were inspiration for my homebuilt dual helix, (long before I happened on this board)..always figured their gnerators were not like our "classic" dual rotor design...hopefully someone will come upon a way to get in their ball park, performance wise without owining a machine shop <G>
spinner

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#39)
by wayne (wayne.jones@sait.ab.ca) on Wed Oct 11th, 2006 at 08:56:58 AM MST
(User Info)

Hey Joseph

I started something like this a little while ago. I used a PVC pipe and only did one coil. Never really tested out with rotor, I might just try this over the winter again.
found a pic.

Wayne

Re: Experimental Windings (3.00 / 0) (#40)
by WXYZCIENCE on Wed Oct 11th, 2006 at 09:31:04 AM MST
(User Info)

Wayne, this is what I woke up to, SNOW.

So technically here it is already winter. Cute little kitty footprints.

Joseph.

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#42)
by wayne (wayne.jones@sait.ab.ca) on Wed Oct 11th, 2006 at 10:38:40 AM MST
(User Info)

Joseph
I am close to rocky mountains and you have more snow. I guess its time to experiment. Today I thought of wiring this one to 6 coils and make it 3 phase. Its tricky with spacing and coil width etc. Have to find some type of rotor and make caps. I am just wondering how much voltage on a single coil vs length and speed. Maybe it could be low RPM generator and simple with just pipe. We see soon.

Wayne

[ Parent ]

Re: Experimental Windings (3.00 / 0) (#45)
by spinner (itsmejonny@email2me.net) on Wed Oct 25th, 2006 at 08:43:04 AM MST
(User Info)

never tried this type of stator...?: isn't it difficult to wind each "coil"?
unless my imagination has gone spacey, I see an image of hand winding, IE poking an end thru the tube, passing it thru, going 'round the outside etc..must be difficult to get it to lay right etc?
kinda like to know if i'm missing the boat
thanx
spinner

Experimental Windings | 45 comments (45 topical, 0 editorial)

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