Planned alternator any suggestions

[Don Cackleberrycreations]

 This is what I have planned

a double disc axial 3phase

disc diameter of 6"

12 magnets per disc  1"diameter  3/4" thick

Would square magnets be a better choice ? say 1" cubes ??

Strator

Will consist of 18 coils (overlapped simular to the one shown on windstuffnow )

8 turns per coil of 16g. for a total leg of 48turns.

Plan is to hand wind the coils around 1/8- 3/16" dowels and mold in place with resin.

I have fantisies of keeping the thickness to 1/2" or less

   Sorry to be so vague Im waiting on a copy of Hugh's book Hoping for some basic formulas on #of turns ect.

This wont be ideal for my wind conditions as the cut in rate will likely be too high.

As the average wind speed in this area is around 7mph though any turbine and tower will have to be able to with stand 80+mph gusts. It will be more of a project to see how well I can do it . The alternator may end up being powered by a small gas engine at some point for use in our RV.

    Any suggestions will be appreciated

[hiker]

not strator--stator--

you must be related to the other guy..

oh well---later.............

[Don Cackleberrycreations]

sorry dislexic cant spell worth a darn

[Gary D]

Hi Don, you are missing some key info.... what diameter blades are you planning? What is your system voltage? And what tip speed ratio (tsr).

Most of us can't spell worth a darn here, and quite a few are using english as a second language, but as long as the info is fairly complete, everyone is happy. Hugh's book will give you many formula's. And his furling tail system can help your mill(s) handle the windspeeds you sometimes get... Perhaps you will want to wait for the book before winding what looks to be too few turns total per phase (depending on size) or too small a gauge magnet wire (could use 2 or more in hand)? Just a stupid wild a*# guess here. Welcome to the board.. Gary D.

[ghurd]

Might want to try 12 magnets 9 coils for the first one.

The overlaping coils sounds kind of 'hard' in a dual rotor. There's a lot of wire at the outside and inside parts, making the stator get thick, fast.

G-

[Don Cackleberrycreations]

Gary thank you.

I realize I have no actual idea of the theory behind these . My comments look to you guys about the same as if you came on the pyrotechnics forum and posted you were going to make a mag55 salute (dont do this BTW mag flash is deadly)or what reistor to use for continuity testing of ematches.  

I would hope to get a rectified voltage of 12volts+ to keep the batteries on the RV up.

With such a small diameter alternator winds would have to be pretty high just guessing but somewhere in the 20mph so it wouldnt be too practicle in my area.

  The simplest would be to start with a wood AX  though this brings up the question of is it possible to use a double rotor on the Wood AX and increase its out put . increase the prop possible 3 blades 5ftD.  Sorry Im grasping here

[motorhead2]

Don,Why not combine your pyrotechnic abilities with low wind conditions.Great advertising and lots of power.Have you thought about a motor conversion at all.

[Don Cackleberrycreations]

Hmm now theres a thought

I have some nice 3 pound drivers that would definately put a turbine up to speed

But Im afraid most neighbors wouldnt enjoy the smell of burnt powder as much as we pyros do.

Then you also have the problems of the BATFE licensing and CPSC hassles. Dont forget EPA who would claim excess nitrates or perchlorates or the NFPA who is seeking a nation wide ban on fireworks. Of course some of these are the same agencies that looked into banning Dihydrogen monoxide (H20 ).

   Old radial air craft engines (some at least did use pyrotechnic starters.

[willib]

Don i just checked , see pic.

for 9 coils 12 magnets of 1" dia you would need a rotor dia of at least 6.932 ".

i like the way you think though , 1" x 1"dia N40 mags have awesome power..

here are the stats :

Grade N40, Dia 1" X 1"

Material: Neodymium grade N40

Magnetization: through 1" length

Rating: 12,900 gauss

Pulling Force: 85 lbs.

Plating: Ni+Cu+Ni

email me , i know where you can get them for $5.99 ea.

if you've never made a three phase alt.the pic wont make much sense,but the three larger circles are coils , inside them are 1" magnets  and the only way they will fit is on a rotor of at least 6.932" in dia.Pay no attention to the inside stuff that was for something else,i just used it as a quick template.

http://www.otherpower.com/images/scimages/2965/don.bmp

[Don Cackleberrycreations]

I notice these would use round coils .

I must not be thinking correctly, I was under the impression you wanted the magnets to pass over straight lines. Round coils would make the coils much easier to wind.

Wound tightly over pvc pipe the pipe section could be left inplace while casting ( this could also be done for ovals or triangular coils by heating the pipe and shaping it to suit)

There is also the point of surface area on the magnet its self , in which case a 1" cube would have more face surface and more total magnetic mass. I'd have to see the magnet field  for different shapes.

  Thank you for simplifing the 30/40 degree I was looking at a 30/20 degree off set Mags to coils and using 18 coils in series of 6 it would have come out to two magents centered on the first and last coil in the series. My misguided thought being to double the magnetic flux intering the coils. The other portion of this thought was to make the coils half as thick to gain staturation. In my drawings there would be no need to overlap.(stone aged drafting compass and protractor)

   The rotor discs arent a big problem I have a number of 6,7,8,10" steel sanding discs 1/4"-3/8" thick .

[willib]

This is a easy to use program , for alt. design and layout.

http://www.emachineshop.com/download/index.htm

This is what i wind the coils with, it looks  different now , i,ve added a wider center , for the 7/8" magnets, and had to add two plastic extenders because the dia. was only 1.5" and i needed 1.75"..

http://www.otherpower.com/images/scimages/2965/Picture_056.jpg

[willib]

I've been using Motorcycle brake rotors .

Can you post a pic of what the sanding disks look like ??

[motorhead2]

The rotor discs would become a problem if their to thin for magnet strenght.Lost possible output.