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New Wind Turbine day 2
By DanB, Section Wind Posted on Tue Jan 18, 2005 at 03:02:44 PM MST
We did a bit more work on Monday

Nothing terribly exciting, but I thought it'd be fun to post a few pictures of the work we did yesterday.

I finished the stator brackets and welded them on. There are 6 brackets, they're from 1.24 X .25" steel bar stock.

Rich came up and made the magnet template for me. You can see here... we're a bit crowded on the inner diameter. But it should work out... were compromising here - getting a bit less than the best bang for the buck from the magnets, but hopefully getting about as much power from the given diameter as possible. Again, these magnets are 1" X 3" X 3/4" thick. When placing these... it requires very careful attention. These make the smaller 1" X 2" Neos we use seem quite tame.

I forgot to get a picture of the finished stator mould (got that done yesterday), but this is the bottom of it. After I layed out the mould, I tried to figure the best coil shape/size. I cut it out from paper to make sure it'd fit OK, and then Ill trace the center out an make a 'spindle' for the center of the coil winder.

Kind of a dark picture, but here it is with the tail on, and 1 magnet rotor mounted. It's nice to have these rotors cut with a water jet. There's no wobble here at all... it turns very true.
Lots of fun. I'm in town today - and have other chores on Wed but hopefully a little more progress will happen on Thurs. I'm dying to get the coils figured out, make a stator.. and test it on my truck!

New Wind Turbine day 2 | 15 comments (15 topical)

Re: New Wind Turbine day 2 (3.00 / 0) (#1)
by iFred on Tue Jan 18, 2005 at 08:15:29 AM MST

Hi Dan!
Nice... I am always asked how the magnet and coil templates line up, in other words how does the coils line up with the magnets? If you could show how this is done, I bet others would finnaly get it, it's one of those things that is most requested. Thanks!
Fred.

>> all energy used to produce this comment or post came from solar and wind energy! It works!

Re: New Wind Turbine day 2 (3.00 / 0) (#3)
by DanB on Tue Jan 18, 2005 at 08:25:25 AM MST

Yes - Ill try to show that. Basicly here, we have 16 magnets, and 12 coils... so at all times 4 coils will be seeing an 'identical' situation with regard to the magnets (theyll be in phase). 4 coils will be in series per phase unless I get impatient and decide to wind this for 12 volts. In that case, I'm afraid Ill have to parallel some coils just to keep the wire size within reason. I doubt Ill do that though - Im leaning towards 48 volts with this one.

Ive actually got a bunch of pictures (from building 10' machines) that really need to be put up - they are much better than anything we have online yet, they show coil placement pretty nicely, there are some where the coils are layed over the magnets that clarify things rather well I think. Just a matter of time.

On this machine (more than most) there will be real compromises made with coil shape, because of how closely the magnets are crowded together at their inner diameter. The 'hole' will be much more like the shape of the gap between the magnets, than the shape of the magnets themselves. There will be some cancellation going on, and I expect it will vibrate a little more than most 3 phase machines (because of a goofy looking sine wave). But I expect itll work fine...

[ Parent ]

Re: New Wind Turbine day 2 (3.00 / 0) (#6)
by Flux on Tue Jan 18, 2005 at 11:36:10 AM MST

Yes I agree, if you could have used 2" x1" x 3/4 magnets it would probably been nearly as good on that diameter, but it will be great anyway.

Its nice to go for a large diameter to use the magnets effectively, then it's tempting to squeeze a few more in and increase the output.

I feel inclined to say that you must be about at the limit for 12v on a machine of that size. I would be tempted to go for the 48v and try to live with it in delta or use transformers to run it at 12v for now.

You could bring the connections out and rectify it in parallel sections for now and connect in series for 48v later if you can live with the rectifiers on the tower.

Flux

[ Parent ]

Re: New Wind Turbine day 2 (3.00 / 0) (#7)
by Ungrounded Lightning Rod on Tue Jan 18, 2005 at 03:42:36 PM MST

I'd be inclined to wind it for 40 if the four coils are in series, but bring the individual coil wires out and connect them on a terminal strip. That way I could connect the stator for 12, 14, or 48 volts.

You'll want to connect them at the stator so you only need three wires down the tower, and that means you have to drop the mill to change the voltage. But that's not the sort of thing you do every day. B-)

[ Parent ]

Re: New Wind Turbine day 2 (3.00 / 0) (#10)
by DanB on Wed Jan 19, 2005 at 06:34:28 AM MST

Hi Flux -

"Yes I agree, if you could have used 2" x1" x 3/4 magnets it would probably been nearly as good on that diameter, but it will be great anyway."

You could be right there... Im doubtful about that though. Poking around with a gaussmeter at 1/2" away from the poles on this, I still find much stronger flux even at the inner diameter (radius a bit over 10") over the poles than I do on the smaller machines that used 1/2" thick magnets, and the moment of cancellation in the legs of the coils will be very brief, so I think the inner part of these magnet rotors will still be quite effective.

"Its nice to go for a large diameter to use the magnets effectively, then it's tempting to squeeze a few more in and increase the output."

Yes. At one point I was considering using 12 of these magnets on here, but after playing with the magnets on thick steel with a Gaussmeter, I felt that I'd pick up a bit more if I used 16.

"I feel inclined to say that you must be about at the limit for 12v on a machine of that size. I would be tempted to go for the 48v and try to live with it in delta or use transformers to run it at 12v for now."

I think the cost of making this run at 12 volts, and the compromises I'd have to live with are probably not worth it. I'm pretty much intending to build it for 48. I need to upgrade my system anyhow. For me, the biggest hassle with upgrading is all my 12 volt lights in the house, and our 12 volt water pump. It scares me a bit to be totally reliant on an inverter for lighting and water.

[ Parent ]

Re: New Wind Turbine day 2 (3.00 / 0) (#11)
by Flux on Wed Jan 19, 2005 at 08:45:34 AM MST

Dan

Are those magnets wider than 1", I have just drawn it out with 1" magnets and your pictures look much more crowdwd at the centre than my drawing.

Flux

[ Parent ]

Re: New Wind Turbine day 2 (3.00 / 0) (#13)
by DanB on Wed Jan 19, 2005 at 10:05:00 AM MST

Hi Flux -
they are 1.5" X 3" X 3/4"

[ Parent ]

Re: New Wind Turbine day 2 (3.00 / 0) (#2)
by picmacmillan on Tue Jan 18, 2005 at 08:23:11 AM MST

hi dan...looks good....i was wondering if the pipe that holds the stator will hold well?..it is cantalevered out and i wondered if that might be alot of stress on the weld itself once you put both plates and the stator on there....it must weigh 50 lbs....do you think a brace between the two would be helpful or do you think the weld will hold?....thanks... :)pickster
http://www.frecklefarmloghomes.com

Re: New Wind Turbine day 2 (3.00 / 0) (#4)
by DanB on Tue Jan 18, 2005 at 08:31:13 AM MST

Yes.. I've thought about that.
I'm inclined to leave it though... it looks nicer I think w/o a brace.
I keep in mind, my current 14' machine is a bit lighter weight - but it's suspended on a much smaller (2" OD), thinner walled 'strut' tube and it seems fine. Matt's 15' machine is the same, but we did add a brace to that one.

This one is held there on 2.5" ID (nearly 3" OD) pipe, and I took great care to weld it carefully. I'm pretty confident with that part... even though I can see your point. My guess is other things will fail first. Perhaps my biggest concern is the weight of the tail right now. The tail bracket is thick (1/2), and the pivot is from very thick walled tubing. On this one I'll not be counting on the 'notch' to stop it - there will be a cable to hold it at normal running position, and another bracket to serve as a postive stop in the furled position so that the blades can never hit the tail. But still... it's going to be heavy!!

[ Parent ]

Re: New Wind Turbine day 2 (3.00 / 0) (#5)
by monte350c on Tue Jan 18, 2005 at 10:06:56 AM MST

Hi Dan

Now I see why the spoked wheel thing wouldn't work on this one - you're packing a lot of punch into a small area!

Looks good - it will be interesting to see the test results.

Ted.

Re: New Wind Turbine day 2 (3.00 / 0) (#8)
by Aelric on Tue Jan 18, 2005 at 06:12:53 PM MST

I have a silly question, how do you hold the magnets down while you are applying the epoxy or fiberglass resin. BTW saw your article in BackHome issue 74 (now will have to at least get issue 75 and 76 to see the rest of it hehehee) really kewl :-)

[ Parent ]

Re: New Wind Turbine day 2 (3.00 / 0) (#9)
by DanB on Wed Jan 19, 2005 at 06:26:29 AM MST

I place the magnets (very carefully) with a plywood template in there. Once they're all down, I remove the plywood template, and run some thin viscosity 'super glue' around the edges of the magnet... it wicks under the magnets pretty well and holds them nicely till we cast resin in there.

[ Parent ]

Re: New Wind Turbine day 2 (3.00 / 0) (#14)
by monte350c on Wed Jan 19, 2005 at 04:30:35 PM MST

Hi Dan,

Will you be offering these magnets for sale? Any idea on pricing yet?

Ted.

[ Parent ]

Re: New Wind Turbine day 2 (3.00 / 0) (#15)
by DanB on Wed Jan 19, 2005 at 05:08:10 PM MST

Hi Ted -
yes, we can sell this size.
Probably $15 - $20 (I need to check, hopefully more like $15) in qty's over 12 or so, and $25 - 30 for small qty. It's about the biggest magnet we stock - right up there anyhow.
I can't remember how many we have.... probably around 100 or so in stock now.

[ Parent ]

Re: New Wind Turbine day 2 (3.00 / 0) (#12)
by troy on Wed Jan 19, 2005 at 09:34:30 AM MST

Hey Dan,

If you're not careful, you're going to start making the commercial boys (those who sell "big" homeowner machines) look really really bad from a $/watt point of view.

Gee, I feel for the commercial outfits. (NOT!)

Thanks Dan!

troy

New Wind Turbine day 2 | 15 comments (15 topical)

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