1.5KW at ground level with chainsaw built blades.

[oztules]

If the power curves is all you wanted to know, then here they are:

The 6.5tsr curve is for an ideal prop. I tried several different tsr curves, and none were even remotely close to working for it. TSR6 didn't develop the power the meters said was coming out, TSR7 didn't get anywhere the revs that were showing, and 6.5 seemed the only near believable curve.

The power curve didn't come out anywhere near what I expected. Several things worked against it I think.

The batteries were truck batteries nearly fully charged (from the dozer and the grader to get 48v.... I don't have a proper bank as yet) This caused the voltage to rise too fast when the current came on. I think this is giving a more idealised figure set for the graph. It came up to 69-71volts @ 21- 23 Amps pretty early in the testing. If it had stayed around the 58-60v mark, I don't know how this would have effected the figures. The alternator is very low resistance so I can assume it would pull the TSR down a bit... but don't know for sure.

Here is the test "tower"

As you can see, it is not far above the ground. This allowed me to test it and at the same time check stator temp. After a sustained 1kw or more for about 5mins, I quickly braked the rotor, and felt the stator. It was barely luke warm. This is a good thing. The time I spent playing with coils and their weights and packing factors.. etc seems to have paid off.

The test bed is in the trailer, and includes a 3ph 3kw motor (4pole) that I wanted to test on the mill. At one stage, the mill was driving the motor full speed, and delivering 19Amps into the battery pack. I'm guessing the motor was drawing at least 300w.

Here is the testbed:

A closer look at the chainsawn blades:

The mill construction is similar to the Dans in most respects. It differs in that I decided to mount the front plate onto the hub, rather than hang it on the stude out the front.

The plates are 14", the mags are 2 x 1/2 N45 the stator coils are 100Turns 1.8mm wire. one in hand.

The construction is like this:

The stator holder is made out of 1/4"x2" steel brace

Here we have the hub on.

From behind we can see the furling stuff

BR>

Side on view

Overhead shot:

BR>

The magnets are set in sand and resin. It's all I had available at the time. Seems to be solid enough. It should hold the magnets no problem. As can be seen, the rear plate is away from the front of the stub axle so the front one can be bolted to the front solidly.

Here we have the stator from Hell. I had it all set up to go when the dog ran in and bumped me while pouring out the hardner. I made an instant decision to go on with it.

Well it hardened in 5 minutes, and was out of the mould in six. Smoke all over the place from the reaction. Luckily I had a mountain of glass matt in there, and placed a garbage bag in the mold to stop the high temp brew from sticking.

It is probably weaker than it should be , although it seems to be very very strong. It all worked, and the stinking hot stator fell out .. melting the bag with it.Oddly enough it works just fine.





So here it stands until I can get a use for it. It generates 1.5kw of power in moderate breezes (30kph or so) is almost silent from adjacent to the blades, and a slight swish from in front and behind them.

My thanks to Hugh (and his book), Danb for his neat head design, and Flux for the thorough beating it has taken to finally understand most of what I needed to know about wind and it's foibles. Now I can play with it up close and first hand..... and Tom for not throwing me out till now.

Hope this brings pleasure for someone, it did for me

..............oztules

[Flux]

Nice work , it looks good.

I like the prop mounted directly on the plate attached to the hub. Blades look nice.

If it is working that well at ground level it will do even better up in clean air.

I suspect you are right about the rising battery voltage favouring the output, it is more favourable than being tied directly to constant voltage. The lower voltage will hold speed down and bring in more stall .

Flux

[oztules]

Thanks Flux. I owe a great deal to you for this result.

The star resistance comes in at 384 feet of 1.8mm wire  ie 6 coils of 64 feet each = .784 ohms.  (@2.042ohms /1000 feet).

With this in mind, I don't see the alternator sagging  as rpm climbs, so I assume that the TSR will suffer. May need some resistance in the line when hooked up to a real bank of flattish batteries...yet to see.

Thanks again..........oztules

[oztules]

That was badly written, that is:

Only 0.784 ohms for 6 coils ie 1 star phase.

Each coil is only .784/6= 0.13 ohms per coil.

I guess Delta is .13x3=.39 ohms per phase.

........oztules

[Norm]

The dog ....man's best friend...eh?

....well most of the time!

Thanks for that amusing (tho not at the time maybe)

 incident.

Very nice work!

[blueyonder]

  you got a good result there ozz.

   as you say all that playing with coils and stuff.

  not to mention the chain saw fun and games.

    and blue blades . yes sum nice pics of how it all went.

   i am still training to be a windgen builder .

   can we get a pic of the dog with a guilty look on his or her face.

[methanolcat]

   Nice oztules,

 A lot of work I know but it's a great feeling to stand back and watch it flying isn't it. Got lucky with the stator, that much wire would have been a shame to lose at today's prices. I bet you was in panic mode when the stator was heating up.

  Congratulations on a job well done, it looks like it will last for quite a long time.

   Matt

[domwild]

Well done, Oz!

We hope the wind stays high on Flinders Island!

Good luck!

[DigitalMind]

Thanks for the write-up Oz,

   Since i'm in the process of learning how to build my own windgen, articles like this really help and encourage me.  

Good Luck !

[thefinis]

Oztules

Very very nice hope you have a tower to fit it when you are through testing. The dog and stator incident gave me a good laugh just glad it all worked out. Shows that the best laid plans can take an unexpected turn when an unforeseen problem arises.

Did you get a chance to see if it furls when expected? I like the rope on the tail for ease of control while testing.

May the breezes blow good fortune your way.

Finis

[blueyonder]

  hay ozz .i am still waiting to see a pic of this dog who put to much hardener

   in the mix.

    you do have a dog right.

   and are you going to paddle all the way to aus and back. is it a field trip.

    bonn - voyage .

[oztules]

There ya go Blue, she bounded into the shed at just the wrong time.... Thats the only time I didn't want a lovable dog wanting to play.

Australia is an hour and a half or so away by air. I don't think I'll paddle, the plane looks a better option. I was going to take the ship, but it looks to be delayed again, so air it is.

..........oztules

[oztules]

Hi Finis

The wind has not been strong enough to test the furling, and the 700cca truck batteries are not strong enough to take the 30 to 40 or so amps that will arrive at about furling for very long. I have already pushed them up to well in excess of 70volts (for a 48v bank), and that can't be good for new batteries.

Waiting for furl I might kill them, so the mill is tied down for the moment.

The tower steel is awaiting attention as well. It is 7 inches diam 1/8th inch high tensile galvanised irrigator pipe. It was in one of those huge travelling irrigators. So it carried a few tons of water about 6 feet above the ground in 12 meter lengths.

I have two lengths of 12m, but will only go 12m high and use the rest as a gin pole and "t" piece on the bottom etc. If this mill can so easily develop 1.5kw at ground level on a mild day, I don't see the need to go too high.

..........oztules

[blueyonder]

 my word ozz. she is a great looking dog.

 in that photo she is smiling as you can tell bye her eyes .

[willib]

Thought i would pop this up to the top, it's really fun reading and has lots of pictures.