Wind Power C

[2win]

Really?! Gorilla Glue works?! Yessss, thanks! I've got that stuff, I didn't think it'd work with wood to plastic, thanks!!!!

Let me know how it goes; I'll be attempting something similar later this week. What thickness balsa are you using?

It's a stick of blasa, about 1/4cm x 1/4cm i think? I'm waiting for it to dry right now (24hrs), but I'm kinda afraid the glue can just peel off the plastic (even though sticking to the wood).. Anyways, but if anyone has heard of E600 or E6000 glue (whichever one it is), it melts styrofoam. don't use it for styrofoam. >.<

[illusionist]

you might want to sand the shiny coating off the front side of the cd before gluing. The film can peal of very easily.

[eeldj123]

Hi guys, I've got a few questions, if anybody is willing to answer them:

1. I have a voltmeter, an load resisters (the 10 ohm ones from radioshack). I looked around and it said i should attach them in so and so manner (voltmeter-resistor-motor). Do I have that assembly correct and should I still have my voltmeter measuring the voltage or should it measure something else? (ex. current and whatnot) Would I also be able to check the power with this?

2. How many volts have you guys been getting before and after the load resistor? I've seen the ones in this thread already and was just curious (I'm getting ~950 mV as of now, without a resistor)

3. What do you think the winning assembly this year will produce?

[chalker]

Hi guys, I've got a few questions, if anybody is willing to answer them:

1. I have a voltmeter, an load resisters (the 10 ohm ones from radioshack). I looked around and it said i should attach them in so and so manner (voltmeter-resistor-motor). Do I have that assembly correct and should I still have my voltmeter measuring the voltage or should it measure something else? (ex. current and whatnot) Would I also be able to check the power with this?

There are 2 wires coming out of the CD motor. Connect one to one end of the resistor and the other to the other end of the resistor. Do the same thing with the voltmeter so that you basically have 2 'nodes' with 3 wires each (voltmeter, cd motor, resistor) touching one another. Here's a simple text based diagram:

Code: Select all

 
    ______________________________
   |             |                |     
Motor         Resistor        Voltmeter
   |             |                |
    -------------------------------

The voltmeter should be set to read millivolts in most cases.

Power is equal to voltage squared divided by the resistance

[eeldj123]

Hi guys, I've got a few questions, if anybody is willing to answer them:

1. I have a voltmeter, an load resisters (the 10 ohm ones from radioshack). I looked around and it said i should attach them in so and so manner (voltmeter-resistor-motor). Do I have that assembly correct and should I still have my voltmeter measuring the voltage or should it measure something else? (ex. current and whatnot) Would I also be able to check the power with this?

There are 2 wires coming out of the CD motor. Connect one to one end of the resistor and the other to the other end of the resistor. Do the same thing with the voltmeter so that you basically have 2 'nodes' with 3 wires each (voltmeter, cd motor, resistor) touching one another. Here's a simple text based diagram:

Code: Select all

 
    ______________________________
   |             |                |     
Motor         Resistor        Voltmeter
   |             |                |
    -------------------------------

The voltmeter should be set to read millivolts in most cases.

Power is equal to voltage squared divided by the resistance

Thanks for the diagram, that made it clear.
Also, since i've seen people mention the voltage with and without the resistor, would I be better off using the voltage with the resistor to calculate the power or the voltage without, and then square the voltage and divide by the resistance? (the last part of "squaring..." refers to both voltages)

[ichaelm]

When you run your turbine without a resistor, it does not generate any electrical energy. It's meaningless to try to calculate how much power it generates, because it doesn't generate any power. Turbines behave very differently with or without a resistor.

Also, make sure you use two of those 10 ohm resistors in parallel! That way the effective resistance will be 5 ohms, which is legal.

[Mr. Cool]

I just have a volt meter and my highest is about 1200 mV. 3 blades made from balsa.

[ichaelm]

The problem is, windmills behave very differently with or without a resistor. The blades I made last year that made the top 10 at nationals wouldn't even turn with the new setup. So make sure you test it out with some resistors before competitions!

[blue cobra]

The problem is, windmills behave very differently with or without a resistor. The blades I made last year that made the top 10 at nationals wouldn't even turn with the new setup. So make sure you test it out with some resistors before competitions!

How could the addition of a resistor make your blades not able to turn?

[ichaelm]

The problem is, windmills behave very differently with or without a resistor. The blades I made last year that made the top 10 at nationals wouldn't even turn with the new setup. So make sure you test it out with some resistors before competitions!

How could the addition of a resistor make your blades not able to turn?

They couldn't generate enough torque to drive the load resistor. There has been discussion about the effect of the resistor elsewhere on this forum that I think explains it well enough if I remember correctly.