Anemometer-generator question

[protox]

New to the forum .
Secondly, I'm in grade 11 physics and we have this project to build an anemometer...

Alright, I have many ideas which may work but don't quite know how to incorporate physics into it...

Well, first off, we don't have a huge budget (below 30 bucks maybe?)...
So the best our class could do would be a cup anemometer...yea simple but I was thinking I turn it into a generator (magnets, wires and so forth) so as it spins EMF/current is induced which is logged.

Now, the problem I'm having now is that how do I relate wind velocity with the voltage(EMF) and current that is produced by the anemometer-generator.

Are they directly proportional? Should I take into account "back-EMF" - higher wind speed means greater EMF but also greater back EMF...

Any information would be helpful!

-protox

 

[Gokul43201]

I thought that maybe you could use a cheap bicycle speedometer to read off the RPMs. Googling for a price for one of these, I came upon this site (it's the secong hit when you google with "bicycle speedometer $") :

http://www.otherpower.com/anemom2.html

Oops, almost forgot : Welcome to the forums !

 

[wais]

Hello protox,

Welcome to the forum! It's great to see you taking an interest in physics and working on a project like this.

Your idea of using a cup anemometer and turning it into a generator is a great way to incorporate physics into your project. The concept of electromagnetic induction is definitely relevant here.

In terms of relating wind velocity to the voltage and current produced by the anemometer-generator, there are a few factors to consider. First, the speed of the wind will determine the rate at which the anemometer spins, which in turn will affect the rate of electromagnetic induction. So, in general, the higher the wind speed, the higher the voltage and current produced.

However, as you mentioned, there is also the concept of back-EMF to consider. This is essentially a counter electromotive force that is generated by the anemometer itself as it spins. This back-EMF can decrease the overall voltage and current produced, and its strength will depend on factors such as the design of the anemometer and the strength of the magnets used.

To accurately measure the wind speed using your anemometer-generator, you may need to do some experimentation and calibration. This could involve recording the voltage and current produced at different wind speeds and creating a graph to show the relationship between the two. You may also want to take into account the back-EMF and factor that into your measurements.

Overall, your project idea is a great way to apply physics concepts to a real-world application. Good luck with your project and don't hesitate to ask for help if you need it!