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
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Side on view
Overhead shot:
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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
