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Forum Index : Windmills : small VAWT project with fuel cell
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| kr3am3r Newbie  Joined: 22/03/2014 Location: United KingdomPosts: 1 |
Hello all, firstly i would like to say that this is an amazing forum, saw a lot of interesting information. Just joined here because i have a problem with a school project. I have to connect a VAWT to a hydrogen fuel cell, which will function as a battery. I will probably connect it to a LED or something as a feedback. I am going to use a DC motor to create the electricity. I have already picked the type of paletes, they will be savonius of about 20 cm diameter and height. My problem is that i don't really know how to control the current in the circuit. I was thinking of using a microprocessor, that will require me to program it and connect a comparator and sensor aswell. Is there a simpler way to control it without using another power supply? If i go with the microprocessor i will have to learn how to program it which will be a pain, thats why im trying to avoid doing this Edit I did not mention why i want to control the current and i am very sorry. When the vawt works it should charge the battery, but when it does not, the LED gets the current from the battery. That is why i think need a microprocessor or if possible a simpler way of control, to make the battery the supply when the power from the vawt drops under a certain value. I am talking about values of 1-5 watts of course. |
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
kr3amkr Welcome to the 4m. Before you get all tangled up in micro-processors and circuit design, make sure your VAWT will actually drive the d.c. motor well enough to charge a battery. Whatever your storage battery's voltage is, the generator will have to surpass that by a volt or two to even get it to work at all. Although it seems almost a no-brainer, I'd bet creating a well-balanced Savonius turbine and actually getting it to produce usable power is going to be the harder of your two projects. Here's wishing you well in your endeavor. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
You have not quoted what sort of current (amps) you expect from your generator and at what voltage. Personally i think you are pushing Sh...stuff up hill with a 200mm Vawt, (or even a 2m vawt for that matter) A Vawt is nominally a slow turning /slow speed high torque mill, where almost all gererator systems need high speed input to work effectively. The basics is you need RPM to produce voltage, as well as rpm to extract torque from the wind speed. What happens is as soon as the generator starts to produce voltage equal or greater than the battery voltage it also starts to load the generator down, this creates what we call "stall" where the power extracted from the wind is not greater than the output load applied. Basically means the turbine is unable to spin fast enough, and produce enough rpm to break free from the loading drag. (like riding a bike with the brakes on) This is why a Hawt is much more efficent, as its a far higher RPM machine, which allows it to break out of stall and produce power at higher rpm. My advice would be to move to a Hawt mill and save yourself the heart ache of trying to flog a dead horse in making a Vawt suit your application (as i doubt it ever will) Have you seen Gizmo's Mini mill here...... http://www.thebackshed.com/windmill/assemblyMini1.asp As you might find you some ideas, and yes you can still use a DC motor with this design. The for a controller have you seen this .......... http://www.thebackshed.com/windmill/articles/TL084-Controlle r.asp Although i do feel there is a few bugs in the actual circuit design, but it will work fine, the bugs are in the way the circuit is adjusted, making it a tedious task, not a non functional circuit. Pete. Sometimes it just works |
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