Modular stator and my new minigen

[willib]

well i got more of the stator finished (one half of it) its a modular stator

i designed it to be taken apart if need be , since i will have all connections to the coils available i can wire it in  standard star , and delta configurations and a version of Jerry-Rigged configuration.

Meaning i could split the phases in half and rectify two coils seperatly , i'm thinking for extreamly windy days to use this configuration .

The machine is a Axial Flux 16 pole 12 coil ,  dual rotor three phase with 7/8"dia x 1/2 inch neo mags, the rotors are 7.688" dia , made of cast iron  which are 0.160 thick.

i've put my money where my mouth is, and wound the coils with smaller than average holes . The holes are 0.46" dia and perform as expected ( exceptionally well) , with very , very nice looking sine waveforms .

That is how i was able to get 78 turns of 0.045"dia wire in a coil measuring slightly less than 1.75" dia by 0.26"

this is a link to an earlier phase of the project.

http://www.fieldlines.com/story/2007/1/12/7217/48715

i did some preliminary testing and it looks as though i am right on target for a 260 RPM cutin for a twelve volt battery.

there are four sections of three coils per section.

there are twelve stator support bolts and twelve connecting bolts which tie the coils together, along with nine wires.

i went with 1/4" coils instead of the 1/2" ones because i could allways wind 12 more. Although its a mind numbing process(winding coils) i got all twelve done!

Pretty soon i will be testing YAY!

More recent pix on the way.!

[willib]

I drilled holes for the wires through the plastic

top view, i'm going to be using the stator mounting bolts for connections as well as the 10-24 stainless ones shown.

all connections on this one are soldered!

i still have to solder the connections to this one

the other two dont have the coil holes in them YET!!

and i havnt epoxied the coils in yet either

[willib]

here i've installed it to see what it looked like... not bad?

here is a good view of how it works , the stator mounts not only hold the stator in place , but serve as connection points for the stator, and i will be taking the power out, from three of them also.

[Jerry]

Hi willib.

First off I must say great work. Your putting forth an awsome effert here. Bravo, I like it.

You are one of the few to question the staus quo (spl(. Thinking outside the box is only going to make things better.

A few questions and you may have allredy answered these so forgive me if you have. What is the plastic stator material?

Is your wire 17 gage? As near as I can tell by my wire conversion chart the closest gage to .045" is 17 gage.

I'm impressed with your small diameter coil center hole and still having good results.

Reason being I'm building several dual rotor test alts and the present unit I'm building has coils slightly smaller then magnet size. I thought at first this might be a problem- although DanB has sugjested it works fine.

The first alt I'm building is the 8 magnet per disc with 6 coils 3 phase. I will build other units latter with the 12-9 configuration.

With the standard 8 magnet per disc and 6 coils wired star the configuration is wired with the 2 coils directly accross from each other in sires. This is phase one. Then do the same with phase 2 and then phase 3. Then the accepted thing to do is wire them star.

I'm doing just that as mentioned above. In this curent small dual rotor I've wound the 6 coils with 19 gage wire.

In star the coils from one phase are basicly in sires with the coils of either of the other 2 depnding on rotor postion.

This then is equal to 4 coils conected in sires.

Do to this "4" # in sires I've also wound 6 coils of 25 gage wire. 25 gage wire is 1/4th the circular mills of 19 gage. 25 gage = 320.4 circualr mills. 19 gage = 1288 circular mills.

In order for 1 coil of the smaller wire to equal 4 coils of the larger wire in voltage it must have the turns count of all 4 of the larger coils.

Therefor I've wound 150 turns per coil of the small wire and 37.5 turns of the big wire. I actuly wound the large wire with 40 turns since its been sugjested here that its unfair to compair star wireing against "Jerry Rigged" since 4 of the 5 volt star coils conected in sires won't equal 20 volts it will only be 17 volt (out of phase coils not working well with each other). Therefor star needs a bit of a handycap to catch up with "Jerry Rigged".

Itresting thing about these 2 coils types. They ocupy the same space and they weigh exactly the same. 1 once each on the postal meter.

Keep this in mind. If your going to do "Jerry Rigged" you must do some math and make each the coils  an equal to the total turns count for 2 phases of normal star.

For example. If you are doing coils for the 12- 9 config. Each "Jerry Rigged" coil would have the turns count of 6 of the star coils and be 1/6th the gage. Simple connecting the same coils either "Jerry Rigged" or star won't produce the desired results.

You could also do "Jerry Rigged" by making each phase have the turns count of 2 phase with wire half the gage of the star phase. Then wire the 2 (for 8-6) or 3 (for 9-12) in sires then off to there own rectifier. This reduce requiered bridge count to 3.

Many posabilities. Keep us posted. I'm following this with great intrest as I'm involved with simular testing.

                         JK TAS Jerry

 

[wil]

Hi willib,

Looking good! I'm cuirous about the plastic also, but I'm almost more interested in where you found cast iron discs?

Cast Iron would be lighter than regular steel. I wonder how much effect this has on response to chaning wind speed. Are there any issues for placing the magnets or paint?

That hub is so darn shiny! did you machine that yourself?

It looks like a freshly machined piece of steel.

What are the set screws for in the hub?

Now I'm heading for your files, to look at the rest of the pics.

Wil

[willib]

I wish i could be of more help!

the wire i got out of solenoids( from a local auto alternator repair place),its

0.045"dia, including the enamel, thats all i know for sure.

wait till he sees what i use it for , he's gonna flip.

the plastic is very neat stuff it is 3/8" thick , cuts/machines  like a dream .

drills fly through it , it not brittle at all , and taps nicely too..

it gives off a slight waxy smell when i drill into it, i have no idea what it

is made of?

i know its not nylon thats much stiffer and harder, i also know that epoxy and

polyester resin have a very tough time sticking to it, and magic marker

just wipes off.

i know it came from a pet store , they used it for filtering the fishtank water

, because i fished most of it out of their dumpster

i was meaning to ask you about those Capacitors that the kids use in auto

stereo systems , have you tried any with your gen/alts yet?

thay have the ability to store power temporarily and feed it to the

batteries,during a lul in the wind , should be good in summertime when the

winds are a lot less than now.

yeah , i understand what you are saying about the jerry-rigged config. 78 turns approx is what i have , and to effectivly use the jerry-rigged setup i would

have to up the turns a bit.

[willib]

The disks are from .....ahhhh , ummmm ,

cooking skillets

 on the bottom it says "8SK" made by Lodge in the good ole' USA

The hub is a VCR head it has two silky smoothe ball bearings in there

the shine is the aluminum

i inverted it and tapped into the holes that were allready in there!

[Flux]

From the description of the plastic it is likely to be HDPE or polypropylene.

Flux

[Nando]

You are doing an excellent job!!

Keep it up !!

Nando

[willib]

With three sections installed #2,#4 and now #3, the results look good !

i couldnt wait till i made the (connecting) wires, so it looks kinda messy

I was finally able to charge a 12V battery , turning the alt by hand!

note i still have to cut the holes ,solder the connectors and install the last section, #1.

battery rest voltage is 11.96 V is an auto battery , that desperatly needs charging!

at 288 RPM ,turning the alt by hand , brought the battery voltage up to 12.22V at .38 A.

by adding the last section ,Should bring the cutin down to ~ 260 RPM, maybe less?

288 rpm is close to the limit that i can spin it , thats why the amps are so low ,because i cant spin it any faster

[willib]

Here i am using Very Large round file , to finish the holes after using a coping saw. it makes quick work of the plastic.

here i got the coils in





this is the underside of the stator section #3





all soldered up





and installed





this is the fun part of all this.

Testing!

dont look at all the connecting wires ! lol

they wont be there when it is properly wired up , well they will be , but they wont be sticking out like that.

with a 6V sla battery ; rest voltage 6.25 V

at 202 RPM i got .74A into 6.83V , here i was limited by the amout of power i could put into it , not the speed.

it got very hard to turn!


"80%" src="http://www.otherpower.com/images/scimages/2965/testing.JPG">


this is my trusty 200watt weller soldering iron, when i was fixing the trigger i noted that the heat is totally from induction.



this is a wireing diagram





[Jerry]

Hi willib.

Yes the old Weller soldering iron is nothing more than a step down transformer.

They are the greates. I findem at garage sales for a couple bux.

Your stator looks much like mine. I stack up wafers of fiberglass shower sheeting.

I cut the hole for this one using a hole saw. I actuly feed the wires between the stacks. Put the coils in then poor the reson in. It makes for a very strong stator.

I'll post all the pix on this one when done. Hey keep up the good work. Looking forward to more test #s.

                      JK TAS Jerry

[ghurd]

Now it's hard to turn (charging), do you think the bearings are up to the job?

Is there any torque related wiggling between the sections?  May be able to dowel the inner sections together for a bit more stiffness.

G-

[willib]

no wiggling that i can tell ?

if the bearing isnt up to the job , then i will replace it

here are a couple more pix.

In this one the rightmost wire is bare #14 from Romex? i think its called ?

i'll be dammed but i cant find the rest of it , so i wired the rest with more of the 0.045 " dia wire.

i think it looks cool! but thats just me?

[ghurd]

"Romex" is a brand name for US house wire.  

Black/white/bare is labeled "600V 14/2 NMB W/G", I think.

Romex type insulation won't take the sun for long.

"i've put my money where my mouth... is... how i was able to get 78 turns of 0.045"dia wire in a coil measuring slightly less than 1.75" dia by 0.26"

I mean leave the outside D the same, but remove 0.090" from the inside Dia.  Just in case you get bored.

And I see what you mean.

No.  It's not just you.  It IS cool!

[willib]

 power output rest Volts of battery = 11.99V

 Volt  RPM  Amps power(Watts)

 12.02 203 .18 2.16 W

 12.07 206 .42 5.1 W

 12.22 228 .88 10.75 W

 12.28 236 1.0 12.28 W

i think an explaination of the graph is needed , although i am very happy with the results the Knee at 230 RPM is a little troubling to me.

i have no doubt that it is caused by the stator resistance , which is around a half an ohm per phase.

which means the alt is starting to buckle at one amp output...on a brighter side i probably would still be winding coils of half the resistance (and double the size or thickness)

Voc = 14.5V at 225 RPM (slightly lower RPM than expected.)

so as a mini gen its not too bad?

much fun was had