New 24V Alternater

[alibro]

Hi guys

First I would like to wish you all a Happy New Year, especially to those of you who kindly spent time answering my earlier questions to help me get this far.

As you can see from the pics I have built a twin rotor 9 coils three phase alternator based on the earlier DanB 10 foot turbines with 2" x 1/2 circular magnets.

I decided to make a test stator to make sure everything fitted and the voltages worked out. You can see one of the coils is made up of two types of wire joined half way and several others have soldered joins too. I know this will probably not take much punishment but I will fly it anyway and see what happens.

To get some of the wire I broke up an old stator and unwound the coils, some of it came from a guy on ebay so I don't know the insulation properties and some came from an old transformer. I know this is not good practice but as this was only ever ment to be a test stator I'm not too worried.

Although you might not see it from this shot these coils are too tall. I made the mandrel for the coil winder a bit over two inches long thinking I would get all the flux from the magnets cutting the coil however I didn't realise until I started making the stator mould that the size of the centre hole needed to be about 5 inches diameter. This pushed the coils out so that they protruded way past the outside diameter of the magnets. For my next one I will make them smaller.

This is the stator ready to come out of the mould. I stupidly forgot to put wax or grease over the screw heads so I had quite a job getting them out.

I have 60 turns of 14# wire approx 1.5mm per coil.

I really should tidy up my bench before taking photos. From this shot you can see the angle the tail is at. I pretty much copied the 10 footers as best I could. Due to the angle the alternator is in the vice and lack of space the tail section is not properly settled down in these shots

The piece of angle iron welded to the back of the upright is to stop the tail swinging into the rotors in a high wind.

This is a good shot from the front. You can see that because I made the coils too long they were are sticking out beyond the magnets. You can also see the jacking stud in the middle. To put the front rotor on or off I grip a length of all thread in my electric drill and it comes off or on in seconds.

I put shrink wrap around the connecting wires on the outside edge, next time I might enclose them in the resin. You can also see I got the position of the right mounting bracket a bit wrong hence the extra bit of iron welded on at right angles. I could have ground it off and rewelded it but I was too lazy.

Now for the exciting bit, open circuit voltages. With the coils connected in Star:-

At approx 60 rpm I got around 9Vdc

At approx 120 rpm I got around 20Vdc

At approx 150 rpm I got around 24Vdc

I connected a multimeter set for frequency onto one phase and it seemed to read 12hz for 120rpm and 6hz for 60rpm. It is very hard to be exact as I was winding by hand and counting off seconds from a watch but the numbers are fairly close therefore when the Voltmeter read 24V and this meter read 15hz I reckoned  it equated to 150rpm approx.

I already have lumber just short of 6 feet long so I will make the blades the full length and if I need to I will cut them shorter however they should be close to the right length for this alternater.

Cheers All

Alibro

[alibro]

Hi everybody

It has been a long time since my last Diary posting and a lot has happened, I was going great guns with my wind turbine project and hoped to get it finished and up during the summer so that I could test everything thoroughly before the winter sets in. Unfortunately my very close friend Gary was tragically killed in a road accident in July. Here is a pic of him helping with my first wind turbine a few years ago.

Needless to say I didn't have much heart in anything for a while, however Gary was a very supportive of my project and I know he would have wanted me to continue, so here is the latest update.

I first balanced the blades by hanging them from a thin wire. The amount of lead you can see on one blade shows how much wood can vary in weight even if all the blades come from the one plank. I guess I should have weighed them before I started carving! To rub salt in I actually made four blades from the one plank but ended up with two heavy and two light. Go figure!!!

I balanced them again when on the alternator as I was a bit concerned I might still get an imbalence when they spin but all seems ok so far.

This is a test raising of the tower. As you can see I made an 'A' frame which might have worked ok with a pulley at the top but was part of the problem which caused my first attempt to fail.

This was the other reason, the winch was not powerful enough. The cables are anchored to a piece of angle iron hammered 5 feet into the ground. Two of them are in very hard ground and are solid enough, the other two have big rocks and a weelbarrow load of concrete poured around the top couple of feet to try and strengthen things up a bit.

For anyone out there who has not raised a tower before these turnbuckles are not recommended. On one test raising of the tower the cable slipped out of the open ended jaw and almost caused an accident. Thankfully no harm was done and I purchased turnbuckles with a bolt at either end for the live event. I also put another cable grip on each connection.

Up

Up

And away

The tower is around 26 feet high and yes I will cut down the hedge around it.

So far this project has taken the best part of a year to get this far, and I still have a good bit to do. I need to get batteries, make a shed for the batteries and inverter, sort out a charge controller and dump load, route the mains into the house and sort out which circuit in the house I will put onto the turbine and arrange a flip over switch so I can use grid power when the wind doesn't blow.

To get this far has been a lot of work but great fun, I will update again when I am using the power of the wind.

So far I have only briefly tested in light winds with a small battery bank and the voltage came up to 30V very easily. This doesn't mean much though as the batteries were small and already charged.

Cheers All

Alibro

PS I am undecided whether I should buy a charge controller (either a Xantrex C60 or Morningstar Prostar 30M) or try to build one. Does anybody have any experience of building a charge controller suitable for a 24V DanB 10 footer?

Also can anyone think of a household item which might be suitable for a dump load? What about a kettle element? Could it be connected to the ac three phase side of the rectifiers or am I being silly?

Any ideas appreciated.

[alibro]

At long last she's flying free!

I first posted about this project almost a year ago (and that was after several months work) so this has been over a year in the makeing, but today I set her free and watched her make good power. I will post pics later but it has been charging a small bank of sla batteries (12 15ah 12V) I found  at work. I brought them home thinking they were good. Unfortunately when I checked them they were only around 5.5V each. I think they must have been disconnected for over a year as they were not required. I figured as they were probably shot anyway I had nothing to lose so I set them up as a 24V bank and connected the turbine. Initially with light winds I saw 4-5 amps and 14V. After around 10 hours the wind picked up a little and I saw peaks of 10 amps at 22V. If my maths is correct that means it was putting out 220 watts in fairly light winds. I know these batteries are not nearly big enough for my system and I have shut the turbine down again for the night but it was great fun to see usable power coming from my own home built wind turbine.

My next step is to get suitable batteries and set up a proper battery bank, then I will have to decide which part of my house to switch over to the RE system and set that up, then I will sort out a dump load using 2 of Ghurd's little circuits. If all this goes smoothly I will splash out on a new inverter as all I have at the moment is a couple of old UPS's.

It is amazing how much work is required to set up a system like this, and how many skills you need, building the alternater is really only a small part of the whole project.