Author Topic: Beginning work on a new wind turbine (strange design)  (Read 1641 times)

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divid

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Beginning work on a new wind turbine (strange design)
« on: January 19, 2009, 07:28:23 AM »
Hello!  I am very new to this and I have no idea what I am doing really... but I want to try my luck at building a wind generator that is a bit different than what I am seeing on these threads.  I watched a show on the science channel on a design that someone is doing that intrigued me so much I want to try to build something that is similar.  I will be putting it a location that has a very generous amount of wind, 15 miles per hour is a low average.


My design will be a bearing-less design (I plan on attempting to levitate my blades using magnets to avoid as much friction and vibration as possible) that is also tailless... the turbine will be a bit like an attic vent (the circular vents that when wind blows they circulate air in and out of the attic) however the blades will be much bigger and only three or four blades. The blades will be very short at the top and expand to be much larger towards the bottom and be bent in a clockwise half-circle so the design will somewhat cone-shaped.  The idea is that the wings will be able to catch the wind at any direction without the need for a tail.


The center of the blades will be sleeve that will be placed over a circular metal bar and levitate due to magnets on the top of pole, the bottom of the pole, and in the middle of the pole while having magnets in the same spots on the sleeve in the center of the blades.  The bottom magnet on the metal pole and the bottom magnet of the blades will have the same pole facing each other to repel each other as will the top magnets.  The middle magnets will be Radial Neodymium Ring Magnets that will also repel each other... the outer diameter of the ring on the pole barely fitting inside the inner diameter of the ring inside the sleeve of the blades, creating the blades to levitate in and up/down direction as well as side to side. I plan on using N45 strength (at the least) magnets so the levitation force will be very strong and I am guessing I will not have more than a millimeter or two of play on the wings side to side or up and down.


The base that the metal bar will be attached to will also house the stator with my coils.  The coils will sit upright and not be incased in resin like the designs I am seeing on most of these except for on the bottom of the coils where I will be securing them to the base... the idea is to let the coils sit free in the air as much as possible to dissipate as much heat as they possibly can.


The magnets will be on the underside of the blades.  There will be two rings of magnets, one on either side of the coils.  


Here are some questions I have in terms of this setup... I have no idea how to measure how fast or slow (in terms of RPM's)this design will work... therefore I am not sure what gauge of wire to use or how many turns to take on each coil, nor do I know how to gauge what startup speed the design will accomplish.  I will have a huge amount of wind, so I am guessing that I will need thicker gauge and less turns, but I know I need to be much more scientific with my approach than to simply guess, but I have no idea how to begin to do accurately measure this.  I plan to add a thermostat to one of the coils that will cross polarity after it reaches a certain degree, but I'm still not sure where to even begin guessing on what wire to use or the number of turns.  Any ideas?


The next problem I have is the securing of the magnets.  They will be block magnets 2 inches long, 1 inch wide and quarter inch thick. there will be a hole in the middle of them with a countersink that will allow me to use a #6 machine screw to screw it down to a metal plate behind the magnet, so the head of the metal screw will be facing the coils (but flush with the magnet's outer edge).... which brings me to eddy currents.  The magnets will be what are spinning, and so I am thinking there will be no eddy current caused by the screw or the metal backing since the screws are not on the stator...they on the magnets where they will keep the same polarity so eddy currents will not be an issue... is this correct?

« Last Edit: January 19, 2009, 07:28:23 AM by (unknown) »

electrondady1

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Re:(strange design)
« Reply #1 on: January 19, 2009, 07:26:33 AM »
i read your post twice and it's still not clear.

sounds like a vertical axis mill.

here is a place that likes to talk about vertical mills

http://www.vawts.net/index.spark

as far as your cogging question goes , screws in the mags won't cause it.
« Last Edit: January 19, 2009, 07:26:33 AM by electrondady1 »

TomW

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Re:(strange design)
« Reply #2 on: January 19, 2009, 07:43:29 AM »
I agree, as clear as concrete, all I got out of it was probably a VAWT with Mag Lev bearings.


Boy talk about starting out in the hole!


Both have been proposed before and, at least WRT the mag lev bearings nothing much has been shown here of a successful unit. Doing both should be interesting, to say the least.


Good luck with it.


Tom

« Last Edit: January 19, 2009, 07:43:29 AM by TomW »

vawtman

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Re:(strange design)
« Reply #3 on: January 19, 2009, 06:52:17 PM »
I agree with Tom on this one.


 Good luck also.

« Last Edit: January 19, 2009, 06:52:17 PM by vawtman »

divid

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Re:(strange design)
« Reply #4 on: January 19, 2009, 08:49:15 PM »
ya, I know, without a picture (and since it is still new in my head and not very clear even to me yet) I am really unable to explain much better... but yes, it is a vertical axis mill that will be levitated using magnets...  Probably too much unknown for it to work, but I figure it's just a pet project and what the heck...


I guess if I do get it to spin, I will just have to guess on wire guage and number of turns until I get it right, unless someone out there knows a way to take an educated guess as to what coils I should use.  

« Last Edit: January 19, 2009, 08:49:15 PM by divid »

jonas302

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Re:(strange design)
« Reply #5 on: January 19, 2009, 09:04:38 PM »
Get it to spin up then test rpm and torque under load  by reseaching  a pony brake or is it spelled prony brake then the smart guys here can give you a real good idea on your coils and turns
« Last Edit: January 19, 2009, 09:04:38 PM by jonas302 »

wdyasq

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De Prony Brake
« Reply #6 on: January 20, 2009, 04:35:19 PM »
« Last Edit: January 20, 2009, 04:35:19 PM by wdyasq »
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