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Dual Rotor Toroid Core PMA build
tecker:
Looks like there's not enough winding room on the inside of the stator core .
jlt:
My thoughts were to wind a stator core much like you would wined a copper coil.But with using mechanics wire.Then encase it in fiberglass.I would paint the mechanics wire with some acrylic
paint put on with a roller To keep it from shorting out .
Not as neat as your Stator but should work.
Eagerly awaiting your progress . thanks for sharing.
JLT
CraigM:
Finding small quantities of silicon steel sheet or strip is a big hurdle for many and it just doesn't seem to be available in the retail market. The next best option is using a very low carbon steel such as 1006 grade which has a .06% carbon content. The lower the carbon content the better and the lower your core losses will be. Annealing the material will also help reduce the carbon content while at the same time adding a resistive oxidation to the outside of the material. Also a very thin material (or wire cross section) will out perform a thicker material. Most silicon steel has a carbon content of .005% or lower.
If you live near a larger metropolitan area you may find scrap metal dealers with silicon steel scrap that's suitable. I live near Phoenix, AZ and there are several scrap metal dealers that have large quantities of silicon steel. Everything from small E cores to untouched sheets nearly 8" x 36". I work at a machine shop and we buy large amounts of sheet metal. I called 6 of our steel vendors asking for silicon steel and none of them knew what I was talking about. I then made a few phone calls to scrap metal dealers and as soon as I mentioned silicon steel they knew exactly what I was asking for. You may want to google "silicon steel scrap" and see what you can find. I've done this also and found material I could purchase at 100 lb. minimums. The scrap yards I've visited sell silicon steel at around $.70 per pound.
Of course if you do find silicon steel the next step is cutting it into strips. We have a guillotine shear here at work so that made it simple for me. However most sheet metal shops have a shear so you may have a friend of a friend of a friend that can help you out.
Another option if you're lucky to come across it is finding the "I" portion of E cores that have the width you need. I found these at a scrap metal yard, still wrapped in paper and fully annealed. (This material is well taken care of at the scrap yard with pallets of it stored in a shipping container) I did a few tests with it by overlapping each piece with the next and tacking them together with a drop of CA glue at the punch hole. I was able to then make lengths suitable for winding.
If anyone in the Phoenix area needs help locating silicon steel drop me an email and I'll let you know where it can be found.
Proof will be in the pudding as to how this PMA works out. I ordered 1" x 2" x 3" C8 ferrite magnets this weekend.
Time will tell,
CM
SparWeb:
Hi Craig,
Have you been able to progress on this project?
(Hoping a little encouragement will help) :)
CraigM:
SparWeb,
I recently moved from Northern Arizona to the panhandle region of Florida and had to put the project on hold for awhile. Took me a month to box everything up and now that I've been here a few weeks I'm staring at a garage full of boxes and wondering where to begin. Honey-do list is a mile long too... sigh.
Have noticed that you can almost watch things rust here. Much different from the dry heat of AZ to the dripping wet sauna that's called Florida.
Should be back at it in a few weeks.
Thanks for asking,
CM
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