Wind energy to electric energy

[Vaibhav Birit]

i want to use non conventional energy source such as Wind energy to charge my Ni-Cad batteries.
Can anyone provide me with an elegant circuit with good explanation for doing the same

 

[williB]

If you can get the correct Shape of Propeller..
hooking it to a small dc motor should give you plenty of current to charge your NiCd batteries..

 

[TillEulenspiegel]

Actually It would help to know the voltage and amp hour rating for the batteries . As far as a propeller , use the fan blades from a window or bax fan. It's premade and el cheep-o

 

[williB]

i found this on a website..i have just seen some Really cool generator blades ..

Wind Power Equation

To predict how much power is available from the wind, you can use the equation below.
Power in watts = (collection area in sq. ft.) (Wind speed in MPH)3 (0.0054)

To illustrate how this equation works, imagine that you have a wind turbine with a diameter of 10 feet (area of 79 sq. ft) that is spinning in a steady 30 mph wind.

According to the equation above, if the generator were 100% efficient, it would produce about 11,500 watts of electricity.

Of course, perfect machine does not exists that can extract all of the available energy.
A more realistic efficiency figure is 30%.
So, using our example above, we could expect our generator, in a 30 mph wind to produce about 3,500 watts of electricity.
Now, if the wind were to increase to 60 mph, according to the equation, the power produced would increase by a factor of eight or 28,000 watts.

 

[williB]

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[Vaibhav Birit]

Thanks WilliB for the excellent pdf suggested. Also thankyou TillEulenspiegel for the info.

I will start building one...

 

[Juglenaut]

How many batteries are we talking about in series that you want to charge?

Using a 540 DC motor or better bearing motors, best would be a brushless motor that is rectified. Motors must be ratio'ed to a gear box or driven directly by a large spur gear and a small pinion gear to be efficient the load form the motor must be as reduced as possible but allow adaquet current and free flowing of the empellers.

Just remember that the energy produced by the generator must be higher than that of the unit being charged, other wise it will just be a fan.

Most DC motors I play around with need to spin way to fast to be pratical for generators with wind to charge a 7.2 volt battery, individual cell is a different case.

I made one out a box fan with a gear the matched to the hub with 4 DC motors, two series in parallel bank with the other two series and some other stuff to make it happen. I found that if closely matched motors work very good for this. This generator produced about 8 volts at 3 amps with a steady 25 Mph wind, it is also good as a DC fan.

 

[williB]

Thanks WilliB for the excellent pdf suggested. Also thankyou TillEulenspiegel for the info.

I will start building one...

youre welcome.. i built one last night .. cant wait to try it out..
did you know that the Savonius wind generators are stackable !!..

 

[TheOne]

I can still remember many years ago, when I had some interest in this subject, reading about the "Darius eggbeater" and other turbines were fascinating stuff.

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"The Darius windmill was named after its French inventor. It is also known as catenary because of its profile when operating. The mill consists of slim aerofoil section blades taking up an oval or rugby ball shape when spinning due to the centrifugal forces exerted. The design gives a high output for the mass of the structure at relatively low cost. Darius units will often not start to turn by themselves and need either an electric start or use a small Savonius unit attached to the top. As the blades revolve they lose some energy as the head into the wind reducing the output."

 

[williB]

I can still remember many years ago, when I had some interest in this subject, reading about the "Darius eggbeater" and other turbines were fascinating stuff.

"The Darius windmill was named after its French inventor. It is also known as catenary because of its profile when operating. The mill consists of slim aerofoil section blades taking up an oval or rugby ball shape when spinning due to the centrifugal forces exerted. The design gives a high output for the mass of the structure at relatively low cost. Darius units will often not start to turn by themselves and need either an electric start or use a small Savonius unit attached to the top. As the blades revolve they lose some energy as the head into the wind reducing the output."

I KNOW it Really IS..!!
the pictures of the 'eggbeater' are awesome.!!
and 500-kW is a lot of power..

 

[williB]

these Savonius wind generators have a lot of torque , for their size..
the one in this pdf.
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currently i have one attached to a small motor/generator..
mounted directly to the motor shaft.
problem is it doesnt spin fast enough..i may have to gear it..
i am getting 1.1 Volts out of it .. when it is in front of a fan..
if i use gears i can increase the speed of the generator although this really complicates the design ..

 

[williB]

unfortunatly i have no experience with gears..
How should i do it??
i think i want the drive gear ( from the Savonius ) to drive a large gear then drive a gear smaller than the drive .?? does this sound right..???

 

[DirtyLude]

unfortunatly i have no experience with gears..
How should i do it??
i think i want the drive gear ( from the Savonius ) to drive a large gear then drive a gear smaller than the drive .?? does this sound right..???

You'd have to show us a picture of the design. It doesn't sound like you made one exactly like the PDF shows. The easiest thing to do would be to use a pulley and belt. Make a larger wheel on the fan and a smaller on the motor. Run a rubber 'belt' between them. That's the easiest way, but it's prone to failure in the long run. I don't know what lifespan you want, but belts tend to slip and get loose, and don't like being exposed to the elements very much.

If you want some decent gears, I got a bunch from All Electronics. https://www.allelectronics.com Go to 'gears' from the main menu, and 'SET OF 5 GEARS AND BUSHINGS'. 5 sets of the assorted gears or $10.00, and they come with adapters.

Anybody making a bigger one of these, I saw a 'How it's Made' show on commercial wind generaters and they were using modified car alternators, which are more efficient then a generator. I would think you could get a smaller version out of a motorcycle or scooter for a smaller turbine. It would still have to be much larger than the project one shown in the PDF.

 

[williB]

Mark you're right i didnt use their design exactly..
below are pics of what i did..
this one is the Savonius wind collector part..

 

[williB]

this one is a close up of how i connected the motor /generator to the Savonius wind collector..that plate (with the screw at either end) above the motor is galvanized sheet metal..what you cant see is the connection of the plate to the nylon pulley connected to the motor shaft..
i had to drill and tap two small screws to hold the plate ..

 

[williB]

I dont know why i didnt check the current before , But i just did and the motor puts out a respectable 0.040 to 0.060 A !! Even when turning very slowly..!! and i got it to produce a maximum of 0.91 mA ..
At one speed it was putting out 43 mV and 62mA , with one meter reading voltage the other reading Amps.
granted as it is now I would need 31 devices connected in series to charge a NiCd but i see potential here...
i was wondering if there was any way to rewind the motor to output more voltage.??

 

[williB]

Maybe by using a higher voltage motor could I get more voltage out ou it..??

 

[williB]

I made one out a box fan with a gear the matched to the hub with 4 DC motors, two series in parallel bank with the other two series and some other stuff to make it happen. I found that if closely matched motors work very good for this. This generator produced about 8 volts at 3 amps with a steady 25 Mph wind, it is also good as a DC fan.

what is a 540 DC motor ?
8 Volts wow , how did you do it??

 

[williB]

Anybody making a bigger one of these, I saw a 'How it's Made' show on commercial wind generaters and they were using modified car alternators, which are more efficient then a generator. I would think you could get a smaller version out of a motorcycle or scooter for a smaller turbine. It would still have to be much larger than the project one shown in the PDF.

the one in the PDF is small, about 5 inches tip to tip..
my new version is almost 8 inches tip to tip , and almost 8 inches high..
next i am going to try a really large one..maybe using a 5 gallon bucket..
i think the trick is going to be to keep the mass of the airfoil as low as possible..

 

[Nigel Goodwin]

what is a 540 DC motor ?
8 Volts wow , how did you do it??

A 540 is a common model makers motor.

The voltage generated depends (obviously) on the type of motor, and the speed you rotate it at. You need to drive the motor quite fast, so gearing up will be essential.