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Step 10Generator Testing
To gather data on the output of the generator, you'll need a few things. Mainly a couple of good multimeters, a test load, and some way to read the RPM.
I attempted to use the equipment in my physics lab and Datastudio to measure the frequency of the AC current, then I tried to work backwards to figure out the RPM of the generator. If I remember correctly, I had to divide by 6 to get the RPMs. This method, however... was extremely inaccurate. I kept getting readings that were very off. Despite the pretty graphs the equipment was generating, I would not recommend trying to use this method for measuring RPM.
Many people use fancy bicycle tachometers with good results. Some bicycle tachometers can be found for under $20. Luckily my physics teacher is an avid bicycle rider and had a box full of old bicycle computers that he let me try out. I found one with an RPM counter and zip tied a neodymium magnet onto one side of the testing jig. Then I used a ring stand and a clamp to hold the sensor in place. Now I could read the RPMs fairly easily, although they didn't update immediately this method was far more accurate. I would highly suggest if you want accurate readings to get a decent tachometer or a bicycle computer with an RPM setting.
I was also able to use Datastudio to measure the DC voltage coming off the generator. The equipment only measured up to 10 volts DC, so I used a simple voltage divider to scale down the voltage being read by the computer. This allowed the computer to read 1/12 the voltage being produced. So the actual voltage on the graph was 12 times voltage read by the computer. See pictures for the schematic. The voltage across R2 should be 1/12 the voltage of the generator, this is shown in the graph.
Also, I needed to flatten out the DC coming off the rectifier. To do this I used a big capacitor in parallel to flatten out the voltage spikes, giving a more accurate DC voltage reading. You have to watch a lot of things when you spin up the generator. It's hardest to measure voltage, current and rpm while still holding onto the drill.
For my test load, I used six 18 ohm 25 watt resistors in parallel for a total of 3.6 ohms.
I attempted to use the equipment in my physics lab and Datastudio to measure the frequency of the AC current, then I tried to work backwards to figure out the RPM of the generator. If I remember correctly, I had to divide by 6 to get the RPMs. This method, however... was extremely inaccurate. I kept getting readings that were very off. Despite the pretty graphs the equipment was generating, I would not recommend trying to use this method for measuring RPM.
Many people use fancy bicycle tachometers with good results. Some bicycle tachometers can be found for under $20. Luckily my physics teacher is an avid bicycle rider and had a box full of old bicycle computers that he let me try out. I found one with an RPM counter and zip tied a neodymium magnet onto one side of the testing jig. Then I used a ring stand and a clamp to hold the sensor in place. Now I could read the RPMs fairly easily, although they didn't update immediately this method was far more accurate. I would highly suggest if you want accurate readings to get a decent tachometer or a bicycle computer with an RPM setting.
I was also able to use Datastudio to measure the DC voltage coming off the generator. The equipment only measured up to 10 volts DC, so I used a simple voltage divider to scale down the voltage being read by the computer. This allowed the computer to read 1/12 the voltage being produced. So the actual voltage on the graph was 12 times voltage read by the computer. See pictures for the schematic. The voltage across R2 should be 1/12 the voltage of the generator, this is shown in the graph.
Also, I needed to flatten out the DC coming off the rectifier. To do this I used a big capacitor in parallel to flatten out the voltage spikes, giving a more accurate DC voltage reading. You have to watch a lot of things when you spin up the generator. It's hardest to measure voltage, current and rpm while still holding onto the drill.
For my test load, I used six 18 ohm 25 watt resistors in parallel for a total of 3.6 ohms.
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www.scoraigwind.com/books/books.htm
If you've got any specific questions I can do my best to answer them, if not the guys at www.fieldlines.com can probably help fill in any gaps.
I think you want a more in depth analysis of the generator. Most homebrew wind power folks won't get that in depth. Basically Hugh's book would outline which generator plans seem to work best partly through trial and error.
I think to get the kind of detail you want, you might consider a different book with more mathematics. However that book might also depend on if you are making an axial flux or radial flux generator.
i have agree with u u r coment i have making for axial flux genereter. but i don't know which parameter using for generotor making, only 30 mtr tower bearing ,gue rope , tail van avalable here but genertor details not avalable
The wiring of the coils is basically a matter of your application and preference (eg. star, wye, delta).