Wood magnet rotors with laminations behind magnets?

[brkwind2]

Can rotors be cut from wood with laminations such as steel banding to glue the magnets to?  I was thinking 3/4" plywood, perhaps doubled on a larger rotor, with half inch on the face leaving a groove for the laminations which would be super glued or epoxied as it was being wound.  Is this feasible?  

I know PMG's have been made with one steel disk magnet rotor & laminations behind the coils but it haven't seen anything with the laminations behind the magnets in an axial flux design.  I'm thinking it may be hard to keep the thing together but maybe purchasing magnets with center holes & putting stainless steel wire around the outside & perhaps adding several stainless screws between magnets, sticking up so that when fiberglass resin is poured it would form around screws helping hold it all together.

[ghurd]

It would work, but wouldn't be as effective due to space between the layers.

Sounds like a lot of work compared to a iron disk. Probably why nobody did it.

G-

[brkwind2]

That was going to be my next question, whether it would be as efficient as a solid steel disk.  I'm trying to figure out a way to get out of cutting 2 large steel disks.  I doubt a 12v inverter on my truck battery & a metal cutting blade on a jig saw would be very fast out in the junkyard either.

[Flux]

Your idea should work but you will probably meet lots of problems. I wouldn't try it on anything other than a small machine.

The rolled strip will be perfectly satisfactory magnetically but there is a large force trying to pull the whole thing out of the groove in the plywood. I have never found superglue capable of anything, good epoxy may do it. You would be safer to gut the groove on the front surface and make holes for the magnets to go through from the back . It would not be as easy but more certain to hold.

There is still the question of strength of the plywood discs and you would need to be careful to take the prop forces directly to the hub.

In the end you would be far better off buying a couple of steel discs if you don't have the facilities to cut your own.

For a machine under 6ft I think the composite plywood steel construction would work in a dry climate ( wouldn't last long here).

Flux

[hiker]

i made a wooden rotor for one of my auto alts--made from plywood disks[4]

i glued the disks togeather--drilled 36 holes for mags and whashers..

i put whashers under the mags-then a screw thru the whashers--mag on top..

worked great--a little to good for a pedgen--36 mags--3 per pole-12 poles..

9coils 3 phase[could have done 18 coils]..

when i get my isp back up ile post some picts--nice little alt-made from-two fronts of

two alts-plus two lams joined togeather--long legged coils-neo powered  :}

[Devo]

I would use round magnets if your going with the wood with laminates then as Flux said cut the groove in the back of the wood for the laminates ,then a hole saw can cut through from the front to fit the magnets on.

Gorilla Glue is good for magnets to steel -I use it on motor conversions so far no magnet has pulled off when installing, I can't say the same for cold weld or JB weld.

Use thick wood for discs as Flux stated if going with a dual rotor.

Personally with a wood/laminate mill I would go with a large Diameter single rotor as it gets rid of many issues with stress on the wood. A 20 inch Diameter ring with 20 poles each pole using a 1/2" thick # 40 -42 neo's with a surface area equal to a 1 x 2 rectangle magnet ,with 15 coils will do an machine in the ball park of hughs 8 footer.

Wire gauge depends on voltage & how it's wired .

Devo