Author Topic: coil winding (Read 12358 times)

delboyo · « **on:** March 13, 2015, 10:44:42 AM »

hello to you all, could someone tell me where I am going wrong with my coil windings please, so far I have wound 15 coils and had to unwind them as they are all different weights, they are 70 turns of 1.7mm,i am trying to build a vawt. I have followed the winding process but keep ending up with different weight coils, is it the number of turns I have to get right or the length of wire being used. I am wasting a lot of wire doing this and it's getting very difficult rewinding them. This is the first time I have wound coils so the problem might be me but I am trying to get them all as close as possible, the weight of the coils vary from 282grams to 383 grams so it is quite a difference, as I said they all have 70 turns. Thankyou in advance to anyone who replies.

Flux · « **Reply #1 on:** March 13, 2015, 01:06:42 PM »

What difference does the weight make, you are not going to spin them are you , so balance is not a problem.

Flux

Flux · « **Reply #2 on:** March 13, 2015, 02:09:58 PM »

Your question aroused my curiosity, I have never weighed a coil before. It is sometimes suggested that you weigh them just as a check that the number of turns isn't drastically wrong.

I have some coils lying around from an alternator that never got built so I have just weighed them as a matter of interest.

The lightest was 343 g and the heaviest was 357g, most are about 352 to 354.

These were wound with 2 in hand wire, no particular effort was spent on them but the turns are all the same ( I use a counter).

If I had been asked to guess how close they would be I would have said 5% so these are close. If they differed by 10% I wouldn't have been worried.

Assuming your turns are correct and you have the right size wire I wouldn't worry. Any attempt at unwinding them and reusing the wire will result in disaster as far as weight uniformity goes. I don't know your source of wire but my suspicion is that you may have bought your wire on small reels and the wire is already pretty kinked. 1.7 mm wire is not nice to use and if it came on a spool of much under 20kg you may well find quite large variation in weights due to the lack of straightness from the reel.

As far as the alternator goes, if the turns are right, the wire is the right size and the coils fit then all will be well. My guess is that you will have far worse variables in the rest of the set up.

Flux

delboyo · « **Reply #3 on:** March 13, 2015, 04:32:39 PM »

thanks for that flux, the wire came on a 4kg reel and as I said I rewound them and yes they are very kinked. I tried to keep them as identical as I could, they are not turning but I thought the resistance in the coils would be different if they were different weights which too me would have meant different lengths. Anyway I will wind the coils 70 turns and see how they work out.thanks for replying so soon to my query.

Flux · « **Reply #4 on:** March 13, 2015, 05:00:47 PM »

You are right that the resistances will be different. If it was for an alternator supplying the grid this would be an issue.

For a wind turbine you could claim it as being a problem or an advantage. If you want to keep things balanced there would be a good case for mixing the coils in each phase so the resistance per phase is as equal as possible.

On the other hand many attempts have been made to get nearer the cube law loading by deliberately bringing one phase in first in low wind and bringing the others in harder as the wind picks up. I won't go into this in any more detail but I did hint at it in my last reply.

If you are building something to a design it is usually best to stick to the design, but if you are doing as I suspect and using an alternator designed for a Hawt on a VAWT then you will not easily know the consequences of any changes, so push on for now and at least get a starting point.

Flux

delboyo · « **Reply #5 on:** March 13, 2015, 08:33:30 PM »

this is my first attempt at building any kind of alternator so I will take your advice and just build it and see how it turns out, I must say the information from yourself and everyone on your site is priceless and I thank you all very much.

electrondady1 · « **Reply #6 on:** March 14, 2015, 08:09:35 AM »

i'd like to see a picture of you coil jig.
and how you wind the coil that is permitting some of the coils to be 30% bigger than others .
one thing you need is consistent tension.

delboyo · « **Reply #7 on:** March 14, 2015, 03:22:16 PM »

The coil jig is the same design as most of the others I have seen on line, turned and wound by hand. I will try to post a picture but I am not very computer savvy, i try to lay the wire in neat rows one on top of the other but the wire seems to have a life of its own and i am forever trying to keep it straight. I tried more tension on it and broke the jig, maybe Flux had a point as 1.7mm is very difficult to wind, my grip is,nt what it used to be so a redesign is probably a good idea.

clockmanFRA · « **Reply #8 on:** March 14, 2015, 03:54:39 PM »

This is Hugh Piggotts design and has worked well for me in winding 40 + coils with 1.8mm diameter wire.

electrondady1 · « **Reply #9 on:** March 14, 2015, 09:54:34 PM »

i checked and 1.7mm is like 14 gauge
which is heavy
did you do a test coil to get the 70 turn coil count ?

can you describe your mag rotors and the nature of your wind mill?
is it drag or lift?

lifer · « **Reply #10 on:** March 15, 2015, 04:28:09 AM »

I have used a coil jig similar to that posted by @clockmanFRA. I have used 1.7mm wire, too, and I must confirm there wasn't any problem at all. All the coils were almost identical (120 turns, only few grams weight difference).

The only (minor) problem was to design a proper coil (jig) width as to have an integer number of turns for a row. Actually, you have "n" turns for the first row then "n-1" on the next one, then "n", "n-1" and so on. I had 8,7,8,7,.. turns on alternate rows thus (8+7) x 8 = 120 turns.

PS: It's funny that this topic has been posted on "Solar" section.. the sun makes the wind blow, after all.

DamonHD · « **Reply #11 on:** March 15, 2015, 06:18:10 AM »

Now moved to Wind (or should that be 'wInd'?).

Rgds

Damon

electrondady1 · « **Reply #12 on:** March 15, 2015, 09:38:33 AM »

i build vertical mills .
the reason i ask about your mill is, lots of guys try to build a vawt and it turns out bad because they copy the design of a horizontal axis machine and the design criteria is different .
there just isn't the rpm available in a vertical.
even a Darius is slower.
which affects cut in speed (point at which charging begins )
which affects the wire gauge.
which affects amperage

to help put tension on you may need to build a type of soft clamp that tensions the wire as you pull it through.
maybe tamp the wire down in the jig as you add turns .

you say you tuned 15 coils which is the correct number of coils it you are doing 3 phase and have 20 poles.
i didn't have much luck with 3phase on my little vertical mills . i needed single phase to get a charging voltage at the rpm i wanted .
anyway, good luck with the project.

XOKE · « **Reply #13 on:** March 15, 2015, 02:57:34 PM »

Hi delboyo, itÂ´s better you use something like this, I use it and winding the coils with 1,6mm2 wire with 2 wires in hand, and they look perfect, and no more than 5% of difference of weight.

regards

Pedro

delboyo · « **Reply #14 on:** March 16, 2015, 03:39:07 PM »

first off I would like to say thanks for the help,electrondady1 the rotors I am using are large pulleys off a belt driven fan,315mm dia 12.5mm thick, they are attached with a taper lock which is self centring onto whatever size shaft you wish to fit them too, they come in various internal diameters, they just lock on with 2 grub screws, and there are 2 of them each holding 12 magnets. My coil winding jig isn't the best I followed Hugh Piggotts design but mine are triangular, the 70 turns are a design I read somewhere on line which I cant seem to find a link to again so I just thought I would give it a try as I had the materials here. I am new to this and am not familiar with what you mean by drag or lift sorry.Pedro that tensioner is perfect, it stops my hands aching after 2 or 3 coils thanks a lot, I just tried attaching some photos but they are to big, the photos are larger than 100KB so I will try later, Best regards Del.

delboyo · « **Reply #15 on:** March 17, 2015, 02:20:10 PM »

these are the pictures I have been trying to upload

Flux · « **Reply #16 on:** March 17, 2015, 02:47:01 PM »

Those coils look perfectly respectable.

Flux

delboyo · « **Reply #17 on:** March 17, 2015, 04:06:47 PM »

Thank you Flux but you didn,t see the ones I threw away, this 1.7 is very hard to get right first time. Del.

hiker · « **Reply #18 on:** March 17, 2015, 08:35:13 PM »

nice....well at least you got the most boring part of the job done ! i really hate winding coils--but they sure look nice once your done !
time to pat yourself on your back......................... :}

delboyo · « **Reply #19 on:** March 18, 2015, 03:44:18 PM »

Advice please anyone,I've made the stator and was in the process of making the rotors and dropped one of them damaging 4 magnets, (these ceramic magnets shatter very easily), is it still possible to make it with 10 magnets on each rotor instead of 12.

XOKE · « **Reply #20 on:** March 18, 2015, 04:42:21 PM »

Hi, what kind of magnets you use? they are ceramic? the flux of ceramic and neo magnets isnÂ´t the same, so the number of turns in the coils in the "ceramic project" its much more.

regards

Pedro

Flux · « **Reply #21 on:** March 18, 2015, 05:23:44 PM »

You must not change it to 10 pole, keep the spacing for 12 pole but leave magnets out in 2 diametrically opposite points if you have to, to maintain balance.

If you have most of the pieces of the magnets you can stick them together without much loss in performance.

Flux

delboyo · « **Reply #22 on:** March 18, 2015, 07:54:07 PM »

I think after doing all this I will send for some new magnets, 3 of the magnets were in pieces on the workshop floor and I didn't find all the bits, thanks for replying and I suppose I will just have to wait.

electrondady1 · « **Reply #23 on:** March 21, 2015, 02:09:58 PM »

too bad about the mags shattering .
good idea to get replacements
the mag rotors look stout .
i don't know what you had planed as a mill but with ceramic mags and 1.7 wire i think you will need to use those rotors as pulleys to overdrive your alternator.

delboyo · « **Reply #24 on:** April 02, 2015, 07:42:45 PM »

Hi to you all again, I have just finished making the rotors and stator and nearly ready to assemble .I think I did what most beginners do and tried to make the stator as flat as possible and ended up sanding a few coils, I hope they work now after all this but at the end of the day it was my fault. the fan (which is off a big industrial airmover), is designed to rotate at between 1400 and 3000 rpm so as long as the wind turns it, it should stay in one piece, the motor it is attached to is only being used as a bearing to run it on, so it is not connected to anything. I changed from a vertical as I read somewhere that a fan is more powerful than a VAWT is that true please. The final design is still on going so I may change it. another question I have is some websites say put as many magnets as possible on the rotor where others say keep a magnets width between them, does it really matter, sorry for all the questions but I would rather find out before rather than after if you know what I mean.

delboyo · « **Reply #25 on:** April 02, 2015, 07:49:16 PM »

mods if I am posting something that is on going should I post it in the original thread or start a new one, sorry if I sound as if I don't know what im doing but I don't.

DamonHD · « **Reply #26 on:** April 02, 2015, 08:08:51 PM »

It's your thread, there's continuity with your previous story; so you can reuse it as you see fit IMHO!

Rgds

Damon

TDC · « **Reply #27 on:** April 03, 2015, 06:37:34 PM »

Yes, horizontal is much more efficient than vertical, but your "fan" looks small. For the generator you made, I would expect 3 blades, around 2 meters in diameter. As for magnet spacing, ceramic is much less powerful than neo, I think that's why more ceramics are used on a given diameter rotor.

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Author Topic: coil winding (Read 12358 times)

lifer