Author Topic: VAWT / PMG design  (Read 1464 times)

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FARU

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VAWT / PMG design
« on: December 06, 2016, 03:58:32 AM »
Hello.

I'm starting a new project, making wind powered light sculptures. My next step is to make a PMG which I can use to experiment with, but I'm uncertain of how to decide the amount and size of magnets and coils.

Each piece will be erected on 12-16ft scaffolding poles in open fields (10mph winds). They are going to be VAWTs, approx 2mx1m. Each turbine will power a 40W or a 60W bulb at 12V and the light will flux in brightness depending on wind speed and therefore express clearly the power source of the sculpture.

I have been looking at Hugh Piggot's online construction manual for a PMG which uses 16 magnets (20 x 50 x 50) and 6 coils (14AWG, 100 windings) and wire this in star. Looking at the graph on page 5 "power vs speed" this design gives a starting speed at 170RPM and at 240RPM reaches 60W.

https://scoraigwind.com/pmgbooklet/itpmg.pdf

As our maximum output is 60W I thought that this design was slightly over the top and wondered if
a) cutting magnet size (to 10x40x40) and coils respectively to this or
b) omitting one ring of magnets entirely would be a possibility?

I am no engineer and I am coming at this project from an artistic side without ever working with kinetic wind turbines before. So any advice you can give me would really be appreciated!

electrondady1

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Re: VAWT / PMG design
« Reply #1 on: December 06, 2016, 06:07:45 AM »
i build vertical axis mills .
i build them narrow and tall to keep the rpm up
verticals rotate at a fraction of the speed of a propeller type
so you will not get the same output .
mine make 14 volts @ 60 rpm.
the top speed is probably less than 200 rpm.
that Hugh Piggot design is for charging a battery it uses a three phase winding layout
because of the speed of rotation i use single phase which requires a coil for every magnet or two phase with two coils for every magnet.
 
are you wanting to run a light system directly off the mill?
if so they will need to LED lights . as an incandescent 40 -60 watt light bulb will stop your mill.




FARU

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Re: VAWT / PMG design
« Reply #2 on: December 06, 2016, 07:01:05 AM »
Sounds like a nice turbine you got going on there! It looks quite accurate to the amount of energy I need and the amount of RPM it'd be working on. If you don't mind sharing... what are the details of your generator?

So, with a single phase system would these coils still be wired in star formation to allow for this lower starting RPM?

I was planning on hooking an incandescent bulb directly onto the mill yep. My concern with LED's was that they are too sensitive - likely to blow and difficult to flux in brightness, but maybe I'll have to look into them more.

Cheers for help electrondady :)

Adriaan Kragten

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Re: VAWT / PMG design
« Reply #3 on: December 06, 2016, 09:57:16 AM »
On my website www.kdwindturbines.nl at the bottom of the menu KD-reports you find several free manuals including drawings of small horizontal axis wind turbines which make use of a simple axial flux generator with only one magnet disk. The generators have not yet been measured but some measurements have been performed on the VIRYA-1.36 generator to determine the number of turns per coil. May be one of these generators can also be used for you project.

electrondady1

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Re: VAWT / PMG design
« Reply #4 on: December 07, 2016, 08:37:46 AM »
you can build the rotors as Hugh has designed but the stator coils will have a different turn count and the copper will be of a finer gauge.
with verticals there is no standard design . every alternator and mill  is an experiment .
what ever the design, you will need to do test coils to see what is required.
set up the alternator on a bench and devise a way to spin it at the same speed as you expect it to turn.
you can even use just one rotor at this point.
if you use 3 phase, 6 coils over 8 mags you are trying to to get your working voltage from only two coils in that phase
doable if you have the rpm to play with but 
 with a reduced speed vertical you will need all the coils passing over all the mags  to get the voltage / amperage you need .

come on back when you get your rotors done
 








« Last Edit: December 07, 2016, 09:17:17 AM by electrondady1 »

FARU

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Re: VAWT / PMG design
« Reply #5 on: December 07, 2016, 08:53:39 AM »
thankyou respondees. 

So would you suggest to mimic Hugh's design with battery sizes but swap out wire to 18AWG. And build a single phase system. 9 coils to 9 batteries.
And build this prototype as a good testing platform to start with this experimentation process.

Cheers!

electrondady1

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Re: VAWT / PMG design
« Reply #6 on: December 07, 2016, 09:21:20 AM »
ah ... its tough at first because your learning a new language.
if you build the rotors like Hugh has designed you will have a good platform for experiment .

FARU

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Re: VAWT / PMG design
« Reply #7 on: December 07, 2016, 10:05:51 AM »
aha,
I didn't get the whole of your last message.
but yes it's true!


I'll get something on the move and let you know how it goes!

Cheers!

gsw999

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Re: VAWT / PMG design
« Reply #8 on: December 13, 2016, 10:32:46 AM »
I am doing this at the moment and I am in the Uk check my youtube Gavin Freedomlover, cheers

crazyguy

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Re: VAWT / PMG design
« Reply #9 on: January 08, 2017, 09:10:24 AM »
Pma's for vawts should be noncogging, axial flux types.
The pma i use is single phase and has separate coils that i can wire together , all in series, or all in prarallel or any combination in between. This allows better matching of pma to vawt. I can choose high voltage low current, or high current low voltage. The coils are in free air and are not potted in resin. Our forum which is a freindly offshoot of the old vawts.net has members from vawts.net on it.
We only discuss vertical turbines. My present project is a Savonius vawt with tsr over 1.5.
  vawtsonly.createaforum.com

We don't allow links, especially commercial ones, until you've established your bona fides, eg as not a SPAMmer.

But since your site seems aggressively unfriendly (and uncommercial) to those not prepared to hand over personal data before even looking (hmm, I'm sure that London sex shops used to be like that, but how would I know?) I've left the name but de-linked it...

DamonHD
« Last Edit: January 08, 2017, 09:44:51 AM by DamonHD »