Wind Power B/C

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Re: Wind Power B/C

Postby science R » Wed Dec 07, 2016 4:09 am

please share some tips to make are turbine faster also what is a good website to find about the history about wind power?

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Re: Wind Power B/C

Postby windu34 » Wed Dec 07, 2016 4:21 am

science R wrote:please share some tips to make are turbine faster also what is a good website to find about the history about wind power?

Make it lighter. Study how real turbines work. The actual construction and some of the design cannot be applied, but you will certainly get ideas from looking through books on turbine design from your local university library

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Re: Wind Power B/C

Postby freed2003 » Wed Dec 07, 2016 5:25 am

science R wrote:please share some tips to make are turbine faster also what is a good website to find about the history about wind power?

play around with pitch, material, and blade number. also where you position the blades and the turbine is relative to the fan.

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Re: Wind Power B/C

Postby Alex-RCHS » Thu Dec 08, 2016 3:11 am

They added a resistor to the setup this year. How does this affect blade design?

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Re: Wind Power B/C

Postby daydreamer0023 » Thu Dec 08, 2016 3:39 am

Alex-RCHS wrote:They added a resistor to the setup this year. How does this affect blade design?


As far as I remembered, we also had a resistor last year as well. It's just that this year, the range of what the resistance can be is larger. Adding resistance means that the blade needs to be able to generate power as it turns. This practically just means that having an extremely fast blade that weighs virtually nothing may not be able to get you as high of a score as a slightly heavier, slower blade.

Since they widened the range of resistance, it probably means that your blade needs to do well under both high and low resistances, as opposed to focusing on just the smaller, lower resistance range from last year's rules.

Let me know if I need to clarify anything!

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Re: Wind Power B/C

Postby RestingDoll » Thu Dec 08, 2016 6:40 pm

daydreamer0023 wrote:
Alex-RCHS wrote:They added a resistor to the setup this year. How does this affect blade design?


As far as I remembered, we also had a resistor last year as well. It's just that this year, the range of what the resistance can be is larger. Adding resistance means that the blade needs to be able to generate power as it turns. This practically just means that having an extremely fast blade that weighs virtually nothing may not be able to get you as high of a score as a slightly heavier, slower blade.

Since they widened the range of resistance, it probably means that your blade needs to do well under both high and low resistances, as opposed to focusing on just the smaller, lower resistance range from last year's rules.

Let me know if I need to clarify anything!


I'm not quite sure I understand why faster blades don't generate more power. The faster the blade, the more revolutions there are that dictate the amount of output voltage; the higher the voltage, the more power generated (v^2/r). Am I missing something here? Or is there another variable attached with maximum voltage?

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Re: Wind Power B/C

Postby chalker » Thu Dec 08, 2016 10:58 pm

RestingDoll wrote:I'm not quite sure I understand why faster blades don't generate more power. The faster the blade, the more revolutions there are that dictate the amount of output voltage; the higher the voltage, the more power generated (v^2/r). Am I missing something here? Or is there another variable attached with maximum voltage?


All other things being equal, a faster blade will generate more power than a slower blade on the exact same setup. The key though is that the resister via something called back-emf actually causes physical resistance to the blade turning. So a blade designed to turn really fast at low resistance might actually end up turned rather slow at larger resistances. The best analogy to this is to consider what would happen if you took a typical airplane propeller and tried to use it underwater as a boat propeller. It wouldn't work very well (assuming you had everything water tight of course and didn't short out the electronics). A boat propeller looks a lot different than an airplane propeller due to the resistance it encounters.

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Re: Wind Power B/C

Postby Alex-RCHS » Thu Dec 08, 2016 11:04 pm

Ok, that makes some sense to me.

Do you all think it would be worth it to buy a resistor and attach it to our testing setup?

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Re: Wind Power B/C

Postby chalker » Fri Dec 09, 2016 12:36 am

Alex-RCHS wrote:Ok, that makes some sense to me.

Do you all think it would be worth it to buy a resistor and attach it to our testing setup?


Yes. Resistors are very cheap. You might be able to disassemble some old electronics and find one you can salvage from them.

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Re: Wind Power B/C

Postby dragon_fruit35 » Fri Dec 09, 2016 1:22 am

noobforce wrote:
andrewwski wrote:
noobforce wrote:What are the barebones materials needed to create the motor?

I have a voltmeter, wires, and a resistor. I understand how to connect everything together what pieces the CD motor is made out of if I'm making it from scratch. I have a limited budget so I want to cut out anything not required.

Is this all I need? How does the motor connect to the circuit?
https://www.jameco.com/z/RF-310TA-11400 ... 38465.html


Thanks.


You're not going to be able to make the CD motor from scratch. If you check Amazon, there's a bunch of them for $7 or less. Ebay has some for even cheaper, but watch out and don't get anything that ships from outside the US - they may take months to arrive.

I'd get a motor with the hub for the CD already on it. Otherwise you could use the motor you linked, but you'd need to create a piece to attach the hub to the spindle.


Thank you, andrew & chalker. So would this product be good? And all I do is connect it to the circuit?
https://www.amazon.com/uxcell-Uxcell-Pl ... s=cd+motor


Just to clarify what the 'CD Motor' does... Is it like a generator, in place of a battery? Does the CD Motor create an emf which causes a flow through the circuit?


This is actually almost the exact motor I used last year. It should work fine! Something the others didn't mention that you'll need is a way to make a stand for your assembly. I used PVC pipe. Also, if I have the time, I can make a circuit diagram for everybody later.

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Re: Wind Power B/C

Postby RestingDoll » Fri Dec 09, 2016 2:26 pm

chalker wrote:
RestingDoll wrote:I'm not quite sure I understand why faster blades don't generate more power. The faster the blade, the more revolutions there are that dictate the amount of output voltage; the higher the voltage, the more power generated (v^2/r). Am I missing something here? Or is there another variable attached with maximum voltage?


All other things being equal, a faster blade will generate more power than a slower blade on the exact same setup. The key though is that the resister via something called back-emf actually causes physical resistance to the blade turning. So a blade designed to turn really fast at low resistance might actually end up turned rather slow at larger resistances. The best analogy to this is to consider what would happen if you took a typical airplane propeller and tried to use it underwater as a boat propeller. It wouldn't work very well (assuming you had everything water tight of course and didn't short out the electronics). A boat propeller looks a lot different than an airplane propeller due to the resistance it encounters.


Does higher resistor mean > physical resistance in this case? If so, would it be best to always test on a 25 ohm resistor?

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Re: Wind Power B/C

Postby windu34 » Fri Dec 09, 2016 4:16 pm

RestingDoll wrote:
chalker wrote:
RestingDoll wrote:I'm not quite sure I understand why faster blades don't generate more power. The faster the blade, the more revolutions there are that dictate the amount of output voltage; the higher the voltage, the more power generated (v^2/r). Am I missing something here? Or is there another variable attached with maximum voltage?


All other things being equal, a faster blade will generate more power than a slower blade on the exact same setup. The key though is that the resister via something called back-emf actually causes physical resistance to the blade turning. So a blade designed to turn really fast at low resistance might actually end up turned rather slow at larger resistances. The best analogy to this is to consider what would happen if you took a typical airplane propeller and tried to use it underwater as a boat propeller. It wouldn't work very well (assuming you had everything water tight of course and didn't short out the electronics). A boat propeller looks a lot different than an airplane propeller due to the resistance it encounters.


Does higher resistor mean > physical resistance in this case? If so, would it be best to always test on a 25 ohm resistor?

Yes; No - you want a turbine that generates high voltage at both resistances. The optimal design should generate the highest voltage at 5 and 25 ohms

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Re: Wind Power B/C

Postby science R » Tue Dec 13, 2016 9:25 pm

What type of material should i make my fins out of for my wind turbine

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Re: Wind Power B/C

Postby chalker » Tue Dec 13, 2016 11:20 pm

science R wrote:What type of material should i make my fins out of for my wind turbine


Anything non-metallic. What do you have readily available? As with all Science Olympiad events, a big part of the value is trying different things out inside of just being told exactly what to do. I'm sure if you look around your home you'd find lots of possible things to use to make blades.

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Re: Wind Power B/C

Postby science R » Thu Dec 15, 2016 9:08 pm

Would you recomend thin material or thick


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