Hello's , Howdie's and a bad stator ?

[ShadeTree]

 First off i'd like to say hello to all, Been read'n this here board for a good 4 years,  guess it was just before the change to the new forum that i stumbled into

this Fine Establishment. Seeking answers i was and answers i found (my thanks to all). in fact tho, over the years i might have done me too much reading,  after awhile all those answers seem to blend together and a mans head gets foggy.

 And that foggy head is what has lead to this post.  

 i built a small generator out of the front spindle and rotor of a 75 1/2 ton chevy

mmm, musta been at least three years ago and right proud i was too, yes sir a right

fine look'n machine it was, darn near perdy to the eyes.  BUT as perdy as it was it

would barely light a single LED (i know,, i know, it were plum embaress'n) still is

now that i think about it..

Which brings me back around to the stator, 12 coils, awg 17, 41 turns, the rotors

have 16 1"x1"x3/16 neos each, the stator is 3/8 thick and the air gap total is 1/2 inch. 16th on each side of the stator.

now when ya hook a load on it it is tuff to turn the blades and forget getting any

speed up. the ressistance is unbelievable.   i'm guess'n i screwed up wiring the

coils together in the stator,

3 phase 4 coils per phase, trouble is i wired from the out lead to the start lead

out lead to start out lead to start on each phase  leaving me with 3 starts and

3 outs.   i have 2 pics uploaded i just can't find the "drop down box" to insert

them in this post..

Could i get one of you fellas to tell me if the wiring is where i went wrong ?

and if so how it should have been done ?

Thanks Much

ShadeTree

[gordon01639]

I'm a relative newcomer but it looks right to me, connect the three start wires together and each of the three out leads goes to a rectifier to convert to DC. There is loads of stuff on here about this just google "rectify three phase" there are quite a few drawings.

Gordon.

Wales in the UK.

[asheets]

The total gap between the coils and the magnets is too much.  

Plus, you might want to check the bearings and whatnot -- unshorted and this airgap should be easy to turn.

Having said that, each individual coil should be able to light up an led or a penlite.  I'd say that if you can't get the entire string to light more than an led, then you've got some of your coils cancelling out the others.

[ShadeTree]

Thanks Gordon and Asheets ?  for the replies,

Gordon wiring the ins together and running the

outs through a rectifier is how i get it to

light the led.

Asheets, ya just can't get the air gap any smaller,

we're talking a 16th on an inch,  i will agree that

the coils are canceling eachother, somewhere i read

about connecting out to out then in to in then back

to out, as i stated earlier i've read so much that

it all blurrs together.

before building a new stator (ole ShadeTree is a lil

light on pocket change)i want to be sure i get it right

next time

as far as the frame, rotors , bearings and all go it turns

fine when no load is applied, with the stator disconnected

it spins up well into the 5 , 6 hunderd range in 20 - 25

mph winds,  but if ya hook the load up it's a bear to spin

it by hand..

oh, i did take an extra coil (same as the others) and with

the stator removed held it between the rotors and at very slow

rpms registerd 1.7 volts (open).

ShadeTree <-- not only can't post pics but his sig is missing too

              ah, there's the sig..

[gordon01639]

Hi again shadetree, I did notice that on your files the picture of the stator 1 of the number 3 coils gos to a number 2 coil, I'm sure you just drew it wrong and didn't wire this way but you never know sometimes  you just do what you see.

Gordon.

In the Welsh valleys.

[asheets]

I must have misread that -- it thought it said that your airgap was .5 inches...

[wil]

Hi ShadeTree,

"have 16 1"x1"x3/16 neos each, the stator is 3/8 thick and the air gap total is 1/2 inch"

I think what asheets was saying is that a 1/2 inch air gap is a little much for 3/16 inch thick magnets.

I believe the rule-of-thumb for stator thickness is to use the same thickness as the magnet. So your stator should be closer to 3/16 of an inch thick.

Wil

[Flux]

"!as far as the frame, rotors , bearings and all go it turns

fine when no load is applied, with the stator disconnected

it spins up well into the 5 , 6 hunderd range in 20 - 25

mph winds,  but if ya hook the load up it's a bear to spin

it by hand.."

This seems to imply that there is not much wrong with the stator.

The only way to find out what is wrong is to do some logical tests.

You need to do these on the alternator and you will probably have to remove the prop.

Join the 3 starts, you have 3 leads (finishes) to play with. Turn the thing at a known speed by hand (120rpm is easy for counting) it should be perfectly free( you say it is)

Measure the AC volts between each pair of leads, should be the same.(meter on AC volts)

Now short all 3 leads, it should be a bear to turn and the drag should be smooth. Disconnect one lead and it should be hard to turn but you should feel it turn in discrete lumps.

If all these steps are ok then your alternator is working properly.

Connect the rectifier to the ac leads but leave the dc terminals open. It should still turn with no resistance and no signs of lumpiness.If you have any resistance or lumpiness then you have a scrap rectifier.

Now measure the dc out of the rectifier ( meter on dc volts), it should be 50% higher than the AC volts that you measured earlier. Short the dc connections and it should be stiff and smooth to turn. If it pulses it shows a rectifier problem.

Once you know the alternator is working properly it is time to see that it is matched to your prop.

Come back with that dc voltage out of the rectifier and the speed you turned it at and also details of your prop.

From your description you seem to have connected the alternator ok. Your 1/2" air gap should be ok. I am beginning to suspect a duff rectifier.

Flux

[ShadeTree]

Morn'n men,  

Gordon,  yeah thats just a bit of an illusion

on that drawing, i did the drawing yesterday

built the stator years ago. it was just to give

an idea on how i wired the coils together.

Thanks for replying Flux, i've followed your

posts for a long time.  i think the rectifiers

can be ruled out as i have tried 4 different and

all new, cept for the one shown in the color pic

that was outta a car alt.  i have even had each

finish (out) with it's own rectifier and still

no difference.

i will take her apart and put the stator back in

to run the tests you suggest, also if i can get

one of my 12 pixel cameras to work i'll get a pic

of the blade,   it's 3 blade, each wing is 3 feet

long, 6 inches wide at the root, down to 3 inches

at the tip.

(that were no typo on the camera pixels)

it'll be days maybe longer tho before ole ShadeTree

can do these things, i have to wait for the weather

improve all my work is done outside, hence the handle

"shadetree"

i might have another pic that at least shows the blade,

if so i'll add it to my user files or if i can edit this

i'll add it here.

one more thought,  a man could turn that rotor 120 rpms

with a load on it or the leads shorted using the blades

for leverage, but it's gonna be TUFF. i was very supprized

at the power 32 of those magnets could produce, which

brings up another idea for a different day...

Thanks again all

ShadeTree

.

[ShadeTree]

here's a couple more pics, to give ya

a better idea of the blade and general

construction..

and ya thought i was kid'n bout those 12

pixel cameras...

ShadeTree

.

[luv2weld]

Did I miss what kind of load you are hooking to the output???

That will make a heck of a difference in how the rotor turns.

Ralph

[ShadeTree]

Hi Ralph,  naw i never really said what

the loads were,  hooking into a 12 volt

battery, or (but here's the kicker) just

putting a led inline after the rectifier(s)

is enough to drag it to a standstill..

and ya have to crank like heck to even

get a flicker out of the led. not cranking

as in high rpms as in over coming a braking

force.

i have a couple other lil mills made from

a 36vdc stepper and a 12vdc volt motor that

will blind ya if ya was to stare at the leds.

a lil more info on the stator wiring,  

each phase was wired then set into the mold

seperately,  i can run current thru each phase

one at a time and the circuit completes.

to me it's like the coils are working against

eachother, but then i ain't certain <--understatement

ShadeTree

[maker of toys]

mmmm.  rolls free with no load, lugs down as soon as a current path is established.

my suspicion:  the recifiers are connected improperly.

with no load, but the rectifiers connected, does it drag, or run free?

(yes, I read the part about 3-4 sets of rectifiers all behave the same.)

-Dan

[ShadeTree]

Morn'n all

    hmmm, it's to bad ya can't see all the

replies while yer reply'n, i have this short

& long term memory thing go'in on.

i can remember the gist's of the replys, just

have a lil trouble connecting names to them.

over the last few years i have spent days standing

out there trying different wiring combinations,

seems i do remember trying just one and then two

phases being wired and getting clogging both times.

actually a jittery electric feeling while turning

the rotor more than a clogging feeling.

i need to run thru all the steps i've done before

just to refresh my brain cells (shouldn't take long

there ain't but a few of'em).

if i end up making another stator i think

i'll do it the old way with the coil leads

exposed so each coil can be tested individually.

might be best for us thicker head types for

learn'n purposes..

Thanks Again, and i promise whilsts i'm out there

              stand'n in the blowing snow and cold

              loosing parts in the drifts i won't

              be cuss'n none of ya's .

ShadeTree

.

[luv2weld]

ShadeTree,

Forgive me if I ask some stupid questions that you have already answered. Just want to make sure I'm reading this right. When you hook the 12v battery to the output, the rotor acts like you put the brakes on? Really hard to turn? Have you double checked the wires from the rectifier to the battery?? Negative to negative?? etc. Also you did check the battery to make sure it is good?? Other than crossed wires, or shorted rectifier there isn't anything I can think of at the moment that would cause the problem.

Ralph

[ShadeTree]

Hi Ralph,

    i'm hope'n it is a problem with

the way i wired the bridge rectifiers.

mostly cause it would save me building

a new stator .

looks like it's gonna be more than a

few days before i can do any trials.

if i ever get this one producing i will

build a slightly bigger one next time.

i don't need much power, i use between

140 and 150 kwh a month and thats with

an electric hot water heater and a well

pump, for years i kept my usage below

100 kwh a month and could get back to that

level if needed.

sorry Ralph i sorta wandered off there,

the battery isn't much, perdy much junk

i  just used it to complete the circuit.

but i get the same results when just trying

to run an led straight fron the gen, plus i

do not get enough power to light the led,

well it does light but only barely at very

high rpms,

as soon as i can i'll use the advice everyone

has given, see what happens and then report

back here.

ShadeTree <-- his bones and the cold do

              not mix well..

.

[ShadeTree]

in the interest of science and furthering

mankind along the path to well where ever

they be go'n,  Shadetree braved the cold

sloppy mess and re-installed the old stator.

But with one tiny lil difference, i flipped it.

i'm happy to report i burnt out 2 10mm leds at

maybe 50 rpm if that many, so on to a lil bigger

test, a 12volt headlight, (ya need to remember

i am turning the alt by hand) now somewhere in

the 100 rpm range i get a RED glow in the

headlight, we're talk'n within a few more rpms

of actual LIGHT !

 since i can't turn it any faster by hand i have

mounted the headlight into the tail and will wait

for mother nature to spin it up.

 i get about the same voltage no matter which

direction i spin the alt. is this normal ?

all in all i think my main problem before was

the stator was backwards,   but then if that was

the case how come i get current no matter which

way the alt spins ?

the drag doesn't seem to be a strong as i

remember, tho it does increase as the rpms

go up..

Thanks for clearing up some of my confusion

on the coil wiring, i came very close to scrapping

the stator several times.. i can make alot of

improvements on the next one,  yup thats right

that old chassis still has another spindle and

rotor on it (:

ShadeTree

.

[ShadeTree]

AH HA, found a problem that is

probbaly costing some power,

it appears i wired the coils

insideout, i reversed the starts

and ends,  i was going back over

this post

http://www.fieldlines.com/story/2003/9/11/84741/6758

which i had studied in the past,

even have 2 copies of it on disk

and still managed to wire the coils

end to start.  

anyone have an idea how much loss

this is causing ?

ShadeTree <--maybe should call self Old Foggy.

.

[ghurd]

Flipping the stator should not matter. The direction of rotation shouldn't matter either. The voltage should be the same.

If the problem was not some kind of connection problem, I suspect there is still a problem.

All I can think of is the magnets are not correct on the rotors.  A WAG.

G-

[Flux]

Agreed, flipping the stator doesn't matter, reversing rotation doesn't matter, interchanging starts for finishes doesn't matter.

Now you have connected a lamp directly to the dc output it will not start in the wind (or lack of it from your pictures). If it does start it will blow the bulb.

These things are intended to charge batteries and you need a different control scheme if you use resistive loading with no battery.

Flux

[ShadeTree]

Hi Ghurd,   there still could be a probblem,

tho having the magnets placed right is the

only thing i am sure of.

Flux,  it's good to know reversing the starts

and finishes doesn't hurt output,

yes i know these are for charging batteries

and yup i have a charge controller that i will

use when the time comes,   the wind, yeah on

my lil test stand it doesn't get much unless

the wind is straight out of the south, then

being channeled between my shack and that line

of trees it gets perdy hairy,,   Truth is if

it blows that headlamp i'll be grin'n fer days.

ShadeTree

.

[Gary D]

 Shade tree, if you have a turning signal bulb assembly handy you might be able to spin up the speed a bit. There is much less resistance there. With a car headlight, you have quite a bit of heating resistance before it lights up(making it harder to turn up to speed). If you do use the test stand as you've suggested, make sure it's weighted down (anchored down)so it won't tip over when a gust smacks the blades!

 The thought occurs that you might have had 2 starts(in's) and one finish(out's) connected before(or the reverse). Possibly you got them correct when you ran your tests this time(just a thought). Not sure how that would react, but think that would be an issue.

 I too watched Gunsmoke quite a few years ago...Festus was a nice guy, liked fishin' as I recall...   Have fun, play safe!   Gary D.

[ShadeTree]

Hi Gary D,  

   oh yeah, the mill has been on

that stand for 3 years,  it did tip

over one time yup that were 2 years

ago. had a lil tornado pass by,  

 the legs (3) cover more ground than

the pics show plus i have 2 couple

hunderd pounds of steel over them.

legs look sumthin like this..

welp that ain't gonna work, i tried

do'n a lil keyboard art to draw the

stand, but it keeps scrambling on

post..

on the wiring, all the outs are grouped

together as are the ins,  it is possible

i had them hooked to the bridge rectifiers

wrong, tho over the years i had tried so

many combinations i shoulda had it right

at least a few times .

i know it has been stated that flipping

the stator should not make any difference

but at the same time i read the "how to"

on building a stator for the 10 foot mill

and in it it states to be careful to lay

the coils in the mold the right side up.

just to be on the safe side next time i

will follow that stator guide to the

letter,  tho right now i'm working on my

"riding battery charger/generator" nut'n

like riding the power to were it's needed..

Agree on the Festus,  a lil rough around

the edges but good people..

ShadeTree

.

[Flux]

That comment about laying the coils the right way up means that you keep all the coils the same way. If you put the lot all in the other way but they are ALL the same way then it doesn't matter, that is what flipping the stator would be the same as.

Placing one coil upside down is the same as reversing the start and finish on a correctly placed coil.

I am sure much of your trouble is in the refusal to use a battery as a load and in the extremely low (useful) wind at your test site. Lamp loads are difficult to start in a decent wind area as you are in stall from the start.

At present all indications are that things are working properly if you can light a lamp by hand cranking.  If it doesn't start, remove the lamp, let it start up to a sensible speed then connect the lamp and see what happens.

Flux

[ShadeTree]

hello again Flux

   i agree the mill is working now,

that is why i moved on to work on my

backup battery charger.

"" I am sure much of your trouble is

in the refusal to use a battery as a

load and in the extremely low (useful)

wind at your test site. Lamp loads

are difficult to start in a decent

wind area as you are in stall from

the start. ""

What refusal ?  i always figured if

i could spin it by hand and lite a

headlight i would know it was working.

being in a low wind area makes it

alot safer to work on,  those blades

when they do catch the wind spin up

fast and have enough mass behind them

to kill.

it gets perdy spooky standing right

behind those blades when they are cranking

6 or 7 hundred rpm,,   even when they are

turning slow it can be quite painful on

the head (trust me i know).

Now , so ya can flip the stator and as long

as the coils were placed and wired correctly

it will work as well either way ??  so then

by flipping it you would be reversing the

"ins & outs"  <-- so it doesn't matter if

the ins come from the inside of a coil or

the outside loop ?  somehow that all just

doesn't register with me..

i know now from the replies that i did

wire the stator going clockwise "in" to

"out" i had gotten my ins and outs confused,

i plan on building one more genny only

doubling the magnet size and maybe 60

turns of awg17,  i already have a set

of 10 ft blades that were to go on the

mill we have been discussing but i don't

believe it produces enough juice to be

tower werthy.

ShadeTree <-- a poor hermit kinda guy who

              lives a no-frills lifestyle.

              a mid-sized genny a few solar

              panels, a backup riding-

              charger and he gonna tell the

              power company where to go..

.