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alumiumn rotors
By kenputer, Section Wind Posted on Wed Jan 26, 2005 at 12:48:04 AM MST
rotors

Has anyone had any dealing with tlgwindpower,I came across them while looking for regulators. They specialize in aluminum rotors. There web site is tlgwindpower.com
Looks like lots of good deals,but are they any good.
kenputer

alumiumn rotors | 15 comments (15 topical)

Re: alumiumn rotors (3.00 / 0) (#1)
by Ungrounded Lightning Rod on Tue Jan 25, 2005 at 05:57:00 PM MST

There have been a number of posts on this board pointing out that aluminum is prone to metal fatigue and breakage when subjected to the kind of repeated stresses you get in a rotor. Unlike steel (which doesn't experience significant fatigue until stressed to a major fraction of its yeild strength), aluminum experiences fatigue under even minor stresses.

I wouldn't use an aluminum rotor for fear of it turning into several-hundred-MPH sword blades some stormy day several years after I instaled it.

(Note that I'm paraphrasing postings of others rather than speaking from my own knowlege on this one.)

Re: alumiumn rotors (3.00 / 0) (#2)
by kenputer on Tue Jan 25, 2005 at 06:03:04 PM MST

I should mention that they do stress that there blades are for low rpm home built machines.

Re: alumiumn rotors (3.00 / 0) (#3)
by juiced on Tue Jan 25, 2005 at 07:26:57 PM MST

I have a bike. I bought this bike for 700$ + a trade in an incredible deal.

This bike has toured a large part of western Canada with me. I have stickers from differant towns all over the bike. I have invested well into 1000$ into it as well.

Its presently for sale @ around 300$ or whatever i can get for it. Why? Well, its not the stickers....

Aluminum is pretty useless after a certain amount of time; in biking standards. Im assuming sub-sonic, free-flying blades are as much of a turn-off as more broken teeth.

Go to any respectable bike manufactuer and they freely give a list of time-tested aluminum. My particular mix was 4 years at 'normal' usage. Normal usage; by definition of thier sites is approx. 6 hours per week riding. LMFAO. I used to spend 6 hours per weeks cleaning....

The point? Aluminum is considered to be a disposable material when used for certain applications. Although, i wouldnt think twice to bring my 6 year, ABUSED bike down a DH or in a skate park.. I cant sell it in good concious for very much more than the great parts. :(

Food for thought.

Canada's -Debatable- A.E./R.E Debate Site
News, discussions and debates!
www.juiced.ca

Re: alumiumn rotors (3.00 / 0) (#4)
by domwild on Tue Jan 25, 2005 at 11:18:10 PM MST

If they are the site that are selling props by the meter, then be warned, these props do not have a twist, nor do they have a taper. It is a standard profile extruded for as long as you need it. I suppose you will just have to buy a longer length or attach more props as they will not be as efficient as the tapered and twisted ones.
dom We only ever use the best fencing wire for our repairs!

Re: alumiumn rotors (3.00 / 0) (#5)
by rotornuts on Wed Jan 26, 2005 at 01:18:11 AM MST

I'm by no means an expert on aluminium but I have the site mentioned bookmarked for curiosities sake and unless I'm mistaken there is like any other metal several grades of aluminium. The blades in question aren't the extruded gyrocopter blades posted a while back, they are formed aircraft grade sheet aluminium. While the blades aren't my favorite, they seem to be simple and reasonably well designed given what they are. I doubt you would experience fatique failure within a reasonable service life simply because of the grade of aluminium used and the fact that the gauge is heavy enough that the blades don't fol over in the first stiff wind. I certainly wouldn't use any old aluminium for blades but I'm willing to give this guy credit that he may have done some homework.

BTW Did you know the space shuttles structure is 90% aluminium?

Re: alumiumn rotors (3.00 / 0) (#8)
by nothing to lose on Wed Jan 26, 2005 at 05:11:10 PM MST

"BTW Did you know the space shuttles structure is 90% aluminium?"

Was that the first one or second one to blow up?? Or is that still the currant model??
.
nothing to lose

Spelin and tpying are my strong points, not electronics.
[ Parent ]

Re: alumiumn rotors (3.00 / 0) (#6)
by Tippy on Wed Jan 26, 2005 at 11:00:55 AM MST

how about aluminum magnet rotors? does it effect the magnet field in any way not to have a steel backing?? i have been thinking about casting aluminum magnet rotors from old tranny cases. also can you get power out of both poles of a magnet. One rotor sandwiched by two stators, with both sides of the magnets exposed. same amount of poles facing the coils, anyone tried a set up like this?

Re: alumiumn rotors (3.00 / 0) (#9)
by nothing to lose on Wed Jan 26, 2005 at 05:20:31 PM MST

That's been covered alot around here about the steel backing. Aluminum is not good at all. Yes you need the steel backing to conduct the magnet flux from one magnet to the other for a return path. The flux field leaves the north flows through the wire to another magnet or steel, it then flows through steel to the next magnet and back through the wire to the magnet on the other side then through steel back to the first magnet it left to begin with. Kinda, sorta, basically, :)
In other words it kinda made a loop and ends up back at it's starting point, then starts the loop over again.

I forget exactly why, but putting the magnets in the center of 2 stators is not good either, various reasons.
.
nothing to lose

Spelin and tpying are my strong points, not electronics.
[ Parent ]

Re: alumiumn rotors (3.00 / 0) (#11)
by Tippy on Thu Jan 27, 2005 at 10:55:46 AM MST

I follow the pricipal of magnet flux to steel or other magnet, what i am trying to describe is a single magnet rotor with both sides of the magnets exposed, a stator on each side with steel banding behind each one, it would be like 2 single rotor alternators with only one set of magnets. That make sense? my question is will using both sides of the magnets (both poles) cut their power in half or is one pole being wasted when they are glude to the steel plates in traditional set ups?
thanks

[ Parent ]

Re: alumiumn rotors (3.00 / 0) (#7)
by Trivo on Wed Jan 26, 2005 at 02:31:46 PM MST

I have a set of the 4 blade 3 foot type and they seem to work well but currently gen in rewind stage so they are not running. Get to there speed and run very quite the metal is quite thick for the actual blade size.
I would think that if the product fell to bits the bloke would be out of business.
Trivo

Re: alumiumn rotors (3.00 / 0) (#10)
by skravlinge on Thu Jan 27, 2005 at 12:41:53 AM MST

There are different kind of aluminum, the metal is not always pure. wind-rotor of aluminum is an alloy used on equipment which have to take a lot of stress.
Aluminum used in a rotor which is less than 10 meters, would not be any risk,
providing it is well manufactured. In Sweden you can see windrotors of aluminum, and they stand. Untwisted blades sold by meters are not twisted, but it has not with the aluminum to do, they can be made twisted.
As with any material, you have to calculate the strength of it for that is to be used for.

This mills are built using untwisted aluminum blades:
http://www.hannevind.com/projekt.htm
-- Always find the typos after posting!

Re: alumiumn rotors (3.00 / 0) (#12)
by Dan M on Thu Jan 27, 2005 at 11:38:06 AM MST

We've got about 40 acres, surrounded by more empty acreage (except during deer season). I've thought about testing a set of blades by putting them up on a pole about 1/4 mile from anything and letting them freewheel without a load for a few months.

Short of a proof test like that, or in-depth finite element analysis along with natural frequency and fatigue analysis, I think aluminum (or even steel) is a little scary.

I think this comes up regularly. I like to summarize my feelings as follows:

If the blades, genny, furling system, etc are ENGINEERED then aluminum or steel should work as well as wood or anything else. But if the method of narrowing in on a solution is backyard trial and error then aluminum steel is scary.

-Dan M

Re: alumiumn rotors (3.00 / 0) (#13)
by Dan M on Thu Jan 27, 2005 at 12:27:31 PM MST

...sorry,

"...aluminum OR steel is scary"

-Dan M

[ Parent ]

Re: alumiumn rotors (3.00 / 0) (#14)
by BuddyL on Tue Feb 01, 2005 at 06:34:11 PM MST

I bought a set of blades from this guy about a year ago. I run them on a 99 volt ametek motor and like them. They went through Ivan in 2004 with winds over 60 mph and still running. They run silent and put out good power they start charging in a bit over 10 mph of wind. I have seen it top out at about 30 amps in wind around 30 mph. All in all is makes a nice small cheap wind genny. The first set of blades were carbon fiber or something like it and they did nothing at all. I put them on a 30 volt ametek and thats about all they can handle and do something. I would have added a photo but it wont let me. Keep up all the good work all!

Re: alumiumn rotors (3.00 / 0) (#15)
by BuddyL on Tue Feb 01, 2005 at 06:46:22 PM MST

This is a photo with an alumiumn blades http://www.otherpower.com/images/scimages/3110/Im000810.jpg

[ Parent ]

alumiumn rotors | 15 comments (15 topical)

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