Wind power generator project

[stevedabear]

Hello everyone,

I'm interested in doing a project which uses renewable energy. Basically i want to use Wind power to Charge up a battery, which then, i can use for my computer during the evenings for instance. Has anybody here tried generating energy from wind? is it possible? Where could i get a decent generator and blade from ?

Any general information will be greatly appreciated.

Cheers

Steve

 

[ante1]

Hi steve,

If you got any wind it is possible! ;D  It depends on how much you like to spend and how much power you need. I helped a friend of mine some years ago with a small wind “powerplant” for charging a 12Volt battery in his fishing cabin. The things we used came from his garage and did not cost anything. He had a big old printer with a couple of fat steppers in it and some pieces of PVC drain pipe and from this we built a Savonius wind turbine. Well a few more parts where used but nothing expensive. 8)

 

[stevedabear]

How much voltage could you get from this system ? and how long did it take to charge the battery?

Cheers

Steve

 

[ante1]

Hi Steve,

The steppers put out about 20V with no load on the rectifiers. The battery was fully charged every time he came to the cabin so I don’t know exactly the charge time. The battery served some florescent light tubes a CB-radio and most important his coffee machine. The highest current we measured was 2A at 14.4V if I remember correctly. It all depends on the things you use, in this case size matters! We had some problems with breakdowns in high winds to begin with but this was solved electronically along the way. Two stepper motors where used, one on top and one at the bottom that served both as alternators and as bearings for the turbine.

 

[Alun]

Ante,
What sort of rectifiers did you use?

If the stepper moters have 4 phases then using two bridge reciefiers you would have a nearly smooth low ripple output without using any filter capacitors.

 

[ante1]

Hi Alun,

I used small bridge rectifiers, four of them for each 6 wire stepper. You can do this in more ways than one, here are some examples. The one I used is the four bridge one!

View attachment 37864

View attachment 37865

 

[Alun]

That's exactly what I was thinking Ante, you'll notice that even if you remove the capacitor (even more on the 6 phase one) you won't have much ripple. This is the bigest advantage or generating DC from a multiphase supply and why it is much better to use stepper motors than carbon brush motors.

 

[ante1]

Yes, the frequency is high that’s why the ripple is low. The caps don’t have to be nearly as big as with 50 or 60Hz. Brushless is maintenance free!  ;D

 

[Alun]

Ante,
Not just the frequency, it's the fact that the motor has more than one phase and the more phases the smoother the output voltage.

 

[ante1]

Hi Alun,

Yes you are correct; the periods overlap each other. To make a good alternator you should try to find steppers with stiff magnets. There is a big difference in the output (as alternator) between different steppers.

 

[Alun]

You'll also be better off using a motor with more steps as the frequency will be higher thue reducing the ripple even more.

 

[ante1]

Yes that’s right, and when I think about it should be even better with two paralleled steppers. If the steppers are mechanically connected with one in “rest” between magnets and the other one on “top” of the magnets there will be twice as many pulses coming out of the eight rectifies. Right?

 

[Alun]

Yes, as you've effectivly doubled the number of phases.

 

[nitrojunx]

hi to all,

i am newbie here. and i have one question about the topic. how about the mechanical part of the wind turbine? is it also moving? in order to keep the propeler blades faces the wind direction?

somebody?

 

[MP1]

You will need some type of control to stay in the wind. For a simple lightweight version, you might be able to use a vane. Larger units are motorized and use a wind sensor for feedback.

Ante, in your last post you mentioned two steppers positioned with one always in the other's half step position for better regulation. How would you be able to do this with wind turbines? I see in rows of large turbines, some always move faster than others. This would take them out of synch. Perhaps some type of brake with a phase sensing feedback? I wonder if such a design would be worth what is achieved, though.

MP

 

[Alun]

MP,
I think Ante was talking about connecting two motors out of phase with each other to the same turbine.

 

[ante1]

Hi nitro,

Welcome to our forum.

MP, Alun,

With the Savonius wind turbine I used there is no need to turn in and out of wind, that’s the reason I chose this type of turbine. This is the first hit of over 300 on a Google search for “Savonius wind turbine “: http://www.ata.org.au/articles/70byosav.htm Here you can see why it’s always in the wind.

The turbine is vertical and I used the two steppers as bearings one on top and on at the bottom. Does this make any sense to you all?

 

[nitrojunx]

ante,

thanks for the info sir, but what i am interested about is the conventional type of wind turbine. the ones that lies horizontally... i have several design of these thing but i cant perfect the mecahnical and the electric transmission from the generator to the load..

 

[steven2]

intersting saw a great wind power generater on the new sieries called beyound tommorow and the thing is wierd instead of blades like a windmill it has a big loop of metal and its twisted on each side to form a blade ,  if ya gona biuld a wind power generater ya would need it to spin a genrater fast when the blades tuirn slow would be my idea so i woud start with useing bycicle parts where the pedels can turn slow and the rear wheel turns faster  or vice versa depeding on the gears and use this idea to make a wind power generater in a larger scale and use the fast turning wheel idea to do the same to a car alternator of which is used to keep the battery in charge then from the battery an inverter to change ya 12 volts dc into house hold power ,  there are other generaters you can biuld like the water powerd generater to which uses the old dyno hub bycicle generater and a bunch of spoons from k mart