3 phase wiring question

[ejl7007]

Hi, I have built this 3 phase alternator out of wood and it has 9 coils.  It is connected in delta.  However I have noticed that when all connections are made I find it difficult to spin the alternator.  I am shorting the wires out?  I do not have this issue if I use a star configuration, as the alternator turns freely when I spin it by hand.

Thanks

[RP]

I believe you have the polarity of one of the coils reversed.

[ejl7007]

Thanks for your help, but no.  All 9 coils are "face-up" I have 18 neo magnets 4"x1"x1" grade N42 on an 18" diameter wooden disk.  The stator has 9 coils of 11 awg wire at 200 turns per coil. All the coils are laid on a 1/2" thick 18" diameter steel plate. The gap between the rotor and the stator is less than a 1/4".  It cogs a bit when it starts up but once going I easily get 14 VAC per phase at about 120 rpm.  

Thanks for your help.

[TomW]

e;

All 9 coils are "face-up" I have 18 neo magnets 4"x1"x1" grade N42 on an 18" diameter wooden disk.  The stator has 9 coils of 11 awg wire at 200 turns per coil. All the coils are laid on a 1/2" thick 18" diameter steel plate.

Not sure how to say this but. You kind of built this bass ackwards as it were.

Magnets must be on steel Coils should not be on steel.

You apparently also missed the fact that a 3 phase machine as built here has one of the 3 coil groups polarity is reversed.

You are making it very hard to get it to work as is.

I am no builder but these are very basic concepts you seem to have missed.

Sorry to bear bad news.

Pull back a bit and read up on it.

Tom

[CmeBREW]

You must of said this backwards, which is confusing as Tom said:

"All 9 coils are "face-up" I have 18 neo magnets 4"x1"x1" grade N42 on an 18" diameter wooden disk.  The stator has 9 coils of 11 awg wire at 200 turns per coil. All the coils are laid on a 1/2" thick 18" diameter steel plate."

You must have the coils layed in 1/2" plywood as some do--and those big 1" thick mags on 1/2" plate steel --in order to be getting 14vac per phase at 120rpm.  Maybe it is just 'eddy currents' in Delta you are feeling? Perhaps the cogging is those big magnets going by the stator's steel mounting bolts? Did you use stainless steel bolts?

If you wish this mill for a 12v system, sounds like you can just "Jerry rig" each phase separately as is, and hook outputs from the 3 rectifiers ,up at the mill,in parallel. 14vac at 120rpm sounds fairly good.

[CmeBREW]

I just saw your other post. Looks like you did some things incorrectly, but no big deal.  You need to re-do some things.

You MUST have those magnets on the 1/2" STEEL disc. You probably have to remake the coils and stator.  Also, 18mags with 9 coils is incorrect. It would cancel out some of the coils and be somewhat like a magnetic brake which is no good.

Also, the steel behind the coils also acts like a big eddy current magnetic brake. No good.

You need to put just 16 magnets on the steel disc and a 12 coil stator.

(Do NOT put 18 magnets on!)

If you only want a single rotor alternator, then make it like this:

 http://otherpower.com/7windturbine.html

With those thicker magnets, It might make a decent 8 footer mill.  

-Good luck.

[ejl7007]

Thank you for your post TomW.  I do have things backwards it seems.  I will try again....correctly.

Thank you

[ejl7007]

Your comments by far have been the most helpful as they are most analytical.  Steel disk with Magnets and coils on plywood.  I had it backwards.  Also 16 mags only and 12 coils would be a ratio of 4/3.  A 3 phase stator wiht four coils in series per phase. Now it begins to make sense.  Unfortunately, I will have a hard time removing the magnets, let alone purchasing more wire and making a new stator.  But I have to do it eventually.  Will take me about a week or so.  I will keep you posted CmeBREW.

Thank you so much for your help.

Cheers

[CmeBREW]

Don't feel bad, I recall I had to clean epoxy off 96 tiny neo magnets on my first attempt when I used plywood with the magnets! We all live and learn.

Use lacquor thinner to take off epoxy. Use latex gloves and soak in the L. thinner for minutes and keep trying to scrape off the epoxy with a knife or something.

Feel free to ask many questions here about wire gauge you should get (probably 14-16ga) and how many turns, etc.   -Thats what these guys are here for.

If you need help in laying out the 16mag/12coil set-up - let us know.

DanB has also made the 16/12 mill also. Look at his 17 footer he made in detail here at this website.

[ejl7007]

Thank you very much CmeBREW, for paying close attention and providing helpful hints.  I will do as instructed and even post pictures of my progress in the near future.  Have a wonderful day!!!

Cheers

Ejl