Charge a battery with pc fans?

[loop]

Here is the exact link of the DC motor application in general

http://www.mini-eoles.com/moteurs%20CA% ... trices.pdf

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[Chatham]

The best performance is obtained by the shapes of airplane propellers, helicopter blades and finally wind turbine blades (derived from helicopters) ... all are quite similar ... it's no coincidence.

It would rather be the gyroplane blades, although a helicopter in autorotation becomes it too ... However, the twist of the blades of wind turbines is very important because of their large diameter and their low speed of rotation.
a PC fan because of the very small active surface would never work as a wind turbine except with a storm wind sufficient to reach 700 rpm which is the speed of rotation of the slowest fans (ultra quiet models).
To test, just put a fan on the door when driving in a car and see the necessary speed

[Billalo]

Hello everyone!
And thank you for your answers!!

a PC fan because of the very small active surface would never work as a wind turbine except with a storm wind sufficient to reach 700 rpm which is the speed of rotation of the slowest fans (ultra quiet models).
To test, just put a fan on the door when driving in a car and see the necessary speed Mr. Green

So according to you, it is very difficult or even impossible to wait for the nominal operating speed because of the surface and the profile of the blades ...
Nevertheless I would like to verify this at least by theory or failing that by practice. Randomly from my surfing today I came across several sites that dealt with the same subject with mathematical formulas but with water. Water and wind are both fluids, right? So would it be correct to use these formulas in my (our) case?

Let us assume that the nominal speed of rotation is attainable. The variations of speed translate well by variations of tensions on this type of gene?
When is it with solar panels (photovoltaic) depending on the amount of sunshine? (I was eyeing the voltage regulators to use with a small photovoltaic panel)
I would like to know if this type of regulator was usable in this application.

Thanks again for all your answers! ^^

[gegyx]

Hello Billalo.

I read you from the start, and I am amazed that before asking all these questions and doing all this research, you did not take a PC fan, plug in a voltmeter and run your fan with supply air?
You might have had the answer to your questions ...

Some time ago, I used a 220v fan and a 110v AC fan, square about 12cm square (which ventilate the machine covers or computer cabinets).
I wanted to use them to make the rotor of a magnetic machine, which would also serve as a generator ... Well, nothing comes out ...

I took a mini 12v DC fan of 4cm, then another of 8cm of PC….
Well nothing .. Maybe 0,002v? Not much.

It was a big disappointment, because I found these machines very practical, as wear-resistant bearing, and possibly to generate a few more W, in order to provide a small punctual impulse, for the same price.

[Billalo]

I read you from the start, and I am amazed that before asking all these questions and doing all this research, you did not take a PC fan, plug in a voltmeter and run your fan with supply air?
You might have had the answer to your questions ...

It is not false!!
It's just that I don't have the gear with me. My multimeter must be at my parents ... well surely ... and I will find a fan there (if they have not thrown all my mess! )
I did not want to reverse engineer the pc on which I work. You never know...

Anyway, this simple experience will not be enough for me. Let me explain :
I will still have a lot of integration (in case of success and in case of failure too) of the genre: At what "speed" are we blowing?
What wind speed would it take to get the desired speed?

I was thinking of using some sort of funnel to increase the wind speed. How fast could we be with this system?

When I ask myself questions, I like to understand "everything" (well the majority). I assume that you have to prepare well for an experiment. Do it and revalidate it or figure out what went wrong.

It is my working method. I hardly have to ask myself any more questions about the time of the experience arrived.
In any case, this is the method that I was taught during my studies !! ^^

PS: I'm still waiting for your answers on the calculation of fluids (water and air ...). In the meantime, I continue my research.

[Christophe]

I took a mini 12v DC fan of 4cm, then another of 8cm of PC…

I confirm, I just tested ... the 2mV that you measure are parasites nothing else ... in short, the pc fan motor is not reversible.

Shame on us for not having tried it before ... especially since it's not the 1st discussion that talks about it!

Morality: better 5 minutes of real test to check some basics rather than more or less speculative discussion hours ...

Let it be a lesson!

KK1 an old bicycle dynamo to test its "reversibility"?

ps: for the "calculations" what exactly do you want?

[gegyx]

Thank you Christopheeven if you didn't say it

The famous bicycle dynamo is actually an alternator.
So it must turn by injecting the 6v AC alternative

I just tested in 6v DC, the roulette makes a U-turn, and waits for the next alternation.

Reedit: the frequency of a bicycle "dynamo" (alternator) must be within 5 Hertz.

[loop]

Hello

It's not easy to compete with EDF, is it?

For the use of motors, which plug into the mains, as a generator, do not be surprised that it does not work
Universal and asynchronous motors have no rotor excitation and therefore, no own induction
Remember to recover a fan, it is possible, if the motor is a DC motor (permanent magnets). For example an engine used in the automobile in 12 or 24 V for the radiator of the radiator or the cabin.
These motors produce direct current with a modest but nevertheless measurable power, even if the shaft is turned by hand
Of course, the higher the nominal voltage of the motor, the more it will reach 12 V at a low speed
For the calculation of the energy contained in fluids, this is of interest only from a certain dimension of helix
For those who want to go further in wind power, I have blade calculation software, recovered from a site
Otherwise look for BETZ's law

Next weekend, if I have time to finish it, I will send you pictures of my modified auto alternator with permanent magnets and rewound

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[jonule]

yes but it's still crazy time!

short for use for something that was not designed for (wind generator) better build it yourself!

in addition it does not cost so much:
http://www.nrjrealiste.fr/eole/eole_elec.html

[Christophe]

Thank you Christopheeven if you didn't say it

Well, I'm far from being a specialist in electric motors ... moreover, it annoys me well ... I would have to go back up a little

The famous bicycle dynamo is actually an alternator.

Ah ... I had always been taught that it was a DC generator ...