output figures for DIY turbine.

[stag]

 At last I have some output dater for my first mill. I have reported that it starts easily with the 3 phase wires shorted out at the foot of the tower and spins up fast as the wind increases.  At furling with 3 phase  shorted out I have recorded 13 amps AC on each phase. Open voltage DC at furling is 35v / 16A. = 560 watts. Into a 12v battery at furling - 16v / 5A . All of these measurements were taken at the foot of the tower. To recap: the alternator Is dual rotor axial flux using 12 ferrite magnets from scrap microwaves on each rotor. These are made from plywood discs with sheet metal from the microwave casings laminated on. The stator is ply with the coils potted with resin into holes in the ply. The ply is faced with glass fibre. There are 9 coils ,3 phase with 90 turns of 1.4mm wire each. The blades are thin aerofoil glassfibre,untapered untwisted set at 4 degrees with steeper angled fins attached at the root to aid start up, 6ft 8" rotor diameter. I now know that the alt could have been more efficient for a variety of reasons, but are the above figures in the ball park?? Comments please.

[gww]

I am compleetly lost when metrics are used for mesurement.  I don't know how thick that wire really is.  sounds like you are getting about 80 watts into your battery.  It also sounds like you need some kind of controller as 16 volts seems very high for a 12volt battery.  I built a ghurd controller for a simular type turbine.  You don't want to buy anything but you are going to have to do something.  The only thing about the ghurd controller is you need the divertion to be about 6 amps per fet so not one big divertion.  I can't believe it even furled when running with open voltage and no load.  It also sounds like you battery was full or small for the voltage to climb that high and to accept so few amps.  I am sure smarter people would be able to look at what you wrote and give advice better then me.  It is nice to see what you are getting with your amp meter though.  Whether it is alot or alittle it is better then a guess.  I would run the battery down a good ways and then see what it does.
Fun to watch
gww

[stag]

gww. yes. battery was at 13.5v. Will try again on a flat one. 1.4mm is near 15AWG.

[gww]

Thanks for the wire comparason.  I will be watching and can't wait to see more.
gww

[stag]

Perhaps I should point out that all of the above figures were recorded at the peak of strongest gusts for a few seconds. Battery charging is usually around 13/14v. I was disapointed at power into the battery. I had assumed that voltage rose as the battery became full but from your observation above, is the opposite the case?

[bob golding]

At last I have some output dater for my first mill. I have reported that it starts easily with the 3 phase wires shorted out at the foot of the tower and spins up fast as the wind increases.  At furling with 3 phase  shorted out I have recorded 13 amps AC on each phase. Open voltage DC at furling is 35v / 16A. = 560 watts. Into a 12v battery at furling - 16v / 5A . All of these measurements were taken at the foot of the tower. To recap: the alternator Is dual rotor axial flux using 12 ferrite magnets from scrap microwaves on each rotor. These are made from plywood discs with sheet metal from the microwave casings laminated on. The stator is ply with the coils potted with resin into holes in the ply. The ply is faced with glass fibre. There are 9 coils ,3 phase with 90 turns of 1.4mm wire each. The blades are thin aerofoil glassfibre,untapered untwisted set at 4 degrees with steeper angled fins attached at the root to aid start up, 6ft 8" rotor diameter. I now know that the alt could have been more efficient for a variety of reasons, but are the above figures in the ball park?? Comments please.

that s seems like a lot of turns  for a 12 volt stator. can you measure the resistance? i would have thought 40 or 50 turns of 1.2mm would be better. you want around 1 or 2 ohms.

[electrondady1]

it sounds pretty good for ceramic mags.

[stag]

Bob.The stator was not specifically designed for12v.   Using the weaker magnets, I just used as many turns of thick wire as possible to hopefully get more voltage,so it was all a bit unpredictable (to me ,at least). I first tried it at 24v, but it only just topped this in a gale before I got it to furl. I switched to 12v, and it seemed to work well. Just luck. Not due to any calculations on my part.

[gww]

Stag
I agree with electrodaddy, it doesn't seem that bad.  I need you to know that I have no more experiance then you.  I only just got a cheap amp meter hooked up to my turbine recently and just got a clamp meter.  I am living through you, cause my turbine is in missouri and I am in indiana.  I only got to play with it for a week or two.  When I make suggestions consider them untested ideals.

I do think you should discharge the batteries and then check it in high winds.  Also you should just see what it does when it just hits the battery voltage and a little above.  16 volts is too high so you need some kind of controller.  I really did like the ghurd controller and you mentioned making heat in a different thread.  I bought the resisters that Ghurd sells and when the batteries are full they do get hot.  I don't think it would heat any kind of area but still neat.  Not real cheap on the resisters and as you know you can do it with other things that you can salvage.

What amps does it put out at the lower charging voltages.  Say 14 volts?

Anyway
Good luck.
gww

[stag]

gww. Thanks for your input. It helps to keep up motivation when others express an interest in what you are doing.  I will record DC amps at battery voltage and also see what I get into a Discharged battery. However! I am going off the idea of battery charging and am pondering more direct uses for the power. We try to grow as much of our food as possible in a temperate climate and my latest scheme is this. Build a small glasshouse close to the mill ,place a glass frame inside this, use heat/light from windpower backed by passive solar(say a couple of drums of water painted matt black) to extend the season to grow salad vegetables hydroponically.NOW! Here's a question. I could just make a resistance coil for the wind heating component BUT, the plants would  also benefit from extra light. I have read that it is possible to run a 12v immersion heater directly from a turbine if the wattage is carefully matched and a small motor cycle battery is used as a buffer to hold the voltage down.,  If this is so, I could substitute the immersion heater for a string of 12v halogen lights and get heat and light from the wind. Question! Even if this would work, will I be losing power by using the battery as a buffer. If so, might it be best to just use a heating coil and so get all of the power??? As usual,I have more questions than answers. Thanks to all for your input

[gww]

My opinion; you have to have a battery and charge controller or a circuit that lets the voltage climb before the resistance load kiks in.  I have tryed strait resistance and the turbine never takes off enough to get anything.  If you have a battery and charge controller you can set the divertion at the high battery setting before it starts diverting.  Then you battery will not run down.  With a starter battery I don't know if they sulphate like a deep cycle would if kept fully charged and not cycled.
Cheers
gww

[stag]

gww. I have already put together a controller with a 30 amp relay,but not used it yet. I guess I should experiment all angles. Re direct connection of resistance load,  the mill starts easily and spins up fast with 3 phase wires shorted out ,so I figured stalling might not be a problem.

[gww]

Just guessing.  Maby it would do ok direct connect.  I don't know what type of wind we are talking.  In lower winds getting more speed first might give a little more.  I can't wait till you try it and tell us.
gww

[stag]

 It starts easily in pretty light winds and spins up fast as the wind increases. All with the AC wires shorted out. I realise this goes against most of what I have read previously, and don't really understand what's happening here. I put it down to alternator inefficiency but then it goes and makes 560 watts open. We have strong winds at the moment, and it's going like a rocket and furling, and yes, the AC wires are shorted out. They were shorted before start up and not after it was spinning. I must experiment with various loads.  Also I will be taking it down soon to make mods to the blades. These GRP chinese blades make a loud whistling noise at much over tick over speed, and I have just discovered on " The Back Shed" how to stop this ( see, improving cheap chinese turbines). But that's another story.

[just-doug]

your voltage seems high to me.ill bet it is cutting in real early,but the weak mags  preventing stalling.a bigger rotor,about 8 feet,would slow the rpm and drop back the voltage. the increase in swept area would boost the total out put.

[stag]

 Doug. Figures apply to absolute peaks of a second duration.  12v peak was into a full battery when voltage would be rising and is more normally 12/14v. I have been monitoring voltage myself, so if I had a controller,there would be no problem anyway. Also I am experimenting with other ways to use the power,and would love to not have any batteries anyway. As the home page of this site wisely says, If you live on the grid, it is not cost effective to use windpower and battery bank instead. I don't think my gen can absorb all of the power from the present rotor, so changing to 8ft blades and getting less RPM would result in less power, not more. I emailed Hugh piggott about the project during construction and he said that he thought his 8ft blades would be too slow for this alternator. I am still learning all the time. There are so many pros and cons with this stuff , it seems that putting a rotor up in the air is the easy part.