Small 3 Phase Alternator

[s4w2099]

Ok, I am building a small alternator for 12V operation. The first step was making the stator windings.

The windings consist of 43 Turns per coil 9 coils 3 per phase. Each Phase resistance is only 0.7 ohms because I used 24 AWG. The size of the rotor is exactly a CD's diameter.

Since I dont have many tools I used two CDs to place the coil in between two, then I taped the edges with duct tape.

<p><BR><img src="http://www.otherpower.com/images/scimages/7350/160600438021.jpg" width=80%><BR>

<p>I get very impatient so I actually baked the stator in my oven because right now the weather is below 32F in my area.

<p><BR><img src="http://www.otherpower.com/images/scimages/7350/160600343173.jpg" width=80%><BR>

<p>After it was all dry the CDs came off very easy except for one part that I had to pry out. The stator came out very nice with minot inperfections. In the center there is a little crack maybe due to the heat applied in the oven and the internal air bubbles expaning (I should have been more patient).

<p><BR><img src="http://www.otherpower.com/images/scimages/7350/160599819269.jpg" width=80%><BR><p>

Next I will put some fiber glass resin and cloth to see if I can cure the cracks.<p>

I will keep you posted.

[willib]

i could tell from your email address that you were into Pic microcontrollers , that CD confirmed it.

i just use ms paint , coppied your pix , used the dotted square , cut the pix resaved them as ,jpg , and renamed them .

welcome to the board..

[kurt]

thanks for resizing those willib i had to remove the  comment with the origanals becouse they were way to large.

[SparWeb]

I don't think your stator would have cracked if you had let it cure for a day before baking it.  Epoxy cures at a rate proportional to temperature.  Putting it in the oven right away caused it to cure too fast, as you suspected.  You can fill the cracks to make it look nicer.

You probably don't need to cover it with fiberglass - it's so small, and relatively thick.  Fiberglass adds surface strength only, but the epoxy binding it softens at the same temperature as the underlying epoxy, so you gain nothing from a heat-stress-deflection point of view.  Two other factors make it worse:  The layer of fiberglass makes your stator thicker (by 1/32", say), and adds thermal INSULATION to the surface of the stator.  

I also put fiberglass on my stator, and I sort-of regret doing so, now.

Good luck.

[s4w2099]

sorry about that man.
:-(

[s4w2099]

Yeah I code the 8 bit ASM :-P

[willib]

I wouldnt use fiberglass either , it looks strong enough as it is.

which PICs do you program?

[s4w2099]

16F84 <-- duh
16F88
16F648A
18F1320

Other PICs would be a matter of reading the datasheet, the concept is the same.