New voltage measurements.

Discussions about solar, wind and radiant energy. Electronics and projects dealing with energy savings.
Post Reply
Electric hobbyist
Posts: 9
Joined: Tue Mar 13, 2012 10:49 pm

New voltage measurements.

Post by Electric hobbyist » Tue Mar 20, 2012 5:08 pm

So far, I have wound 8 coils of magnet wire, did a voltage measurement on one, and got a maximum reading of .025 volts holding it close to the magnetic rotor while spinning the rotor. Put together, I estimate that they would generate about a fifth of a volt of electricity. I am aiming for an output of at least 30 volts of electricity from my homemade project. Is it, in any way, normal at all for these homemade generators to only generate a couple volts maximum? Or is there, hopefully, a way to get a higher voltage output on these things?

techman
Site Admin
Posts: 1329
Joined: Thu Dec 22, 2011 11:49 am

Re: New voltage measurements.

Post by techman » Tue Mar 20, 2012 8:21 pm

Voltages in the range of 30 to 50 volts are common with total output energy of hundreds of watts.

How many winds are in your coils? What gauge wire are you using? What type and grade magnets are you using?

Ceramic magnets will not produce much energy. And to test the output, you will need to be nearly touching the coils to the magnets.

Are you measuring with the meter on AC or DC? With our without a rectifier?

Another huge point is that you are now using an "air core" coil. If your coil is wound around a metal (not solid) core, you will see much higher voltage readings. Use laminated layers of metal sheets, strips of painted or coated wire to make a metal core for your coils. Many people go to the beach with a plastic bag and a powerful magnet to get tiny magnetic shavings out of the sand. These are then used with glue to make a magnetic core for your coils.

The best way to test your generator output is to mount a coil on the stator and the magnets on your rotor and put it all together. The spin it up while testing the voltage. This is the most controlled environment for testing your voltage.

Please let me know how it goes.

Electric hobbyist
Posts: 9
Joined: Tue Mar 13, 2012 10:49 pm

Re: New voltage measurements.

Post by Electric hobbyist » Wed Mar 21, 2012 8:29 pm

I am using roughly 28-30 gauge magnet wire with roughly 25-35 turns per coil, open air in the center of the coils (the center of each coil has nothing but only open air within), and am using N45 grade Neodymium magnets that are 1 inch long, a half inch wide, a quarter of an inch thick, are polarized through the thickness, and have, according to whoever sold them to me on Ebay, a pull of roughly 19 pounds per individual magnet. And as you have likely seen, I have 16 of those magnets glued to the rotor. I tried both AC and DC on my meter and got pretty much the same results on both.

techman
Site Admin
Posts: 1329
Joined: Thu Dec 22, 2011 11:49 am

Re: New voltage measurements.

Post by techman » Wed Mar 21, 2012 9:06 pm

The magnets are good. That is what I am going to use for my next genny.

You do need to put some metal in the coils, as I mentioned before. And try larger coils. A lot more turns per coil. I was just fixing a hand crank LED lamp last night. The coil has maybe a hundred turns of super fine wire and puts out maybe about 2 - 3 volts and a few miliamps. But the point is it has a lot of turns of wire.

Have a look at the insides of a DC motor for an idea how it is formed. The coil core is layered metal. Each layer is varnished in between to electrically separate them from one another. The magnetic particles from sand, or metal filings from a metal lathe (such as at a mechanic who turns brake drums) will work.

I hope this works well for you. Please keep me posted.

Electric hobbyist
Posts: 9
Joined: Tue Mar 13, 2012 10:49 pm

Re: New voltage measurements.

Post by Electric hobbyist » Thu Mar 22, 2012 1:08 am

I do have a spool of 35 gauge magnet wire. Would that be any good, or is 35 gauge too thin for anything over 10 volts? What gauge wire do you recommend?

Also, I made my coils so that the inside opening is roughly the same width as the individual magnets, and about a couple milimeters longer than the length of each individual magnet. I also tried even making smaller coils and putting those within the larger coils to make a "coil inside coil" configuration, and I am still getting about the same readings when I even connect both coils to the voltage meter.

techman
Site Admin
Posts: 1329
Joined: Thu Dec 22, 2011 11:49 am

Re: New voltage measurements.

Post by techman » Thu Mar 22, 2012 8:55 pm

The voltage is increased by increasing the number of turns per coil.

But the wire gauge will affect the max current output. The 35 ga wire is a bit small. I would use between 18 to 23 gauge, if I had a choice. I have seen even larger diameter wire used for high power generators. Larger wire has less resistance, therefore it can flow more current with less heat generated in the coils.

But at the price of copper, I would try about 500 to 1,000 turns of your 35 ga wire and see what it produces before you go out and buy another spool of wire. Dont forget to use a metal core of some type to increase power overall.

Electric hobbyist
Posts: 9
Joined: Tue Mar 13, 2012 10:49 pm

Re: New voltage measurements.

Post by Electric hobbyist » Fri Mar 23, 2012 5:14 pm

The thickest gauge wire I currently have (but not much of left) is 24 gauge. The thickest I have a whole lot of right now is 25 gauge.

techman
Site Admin
Posts: 1329
Joined: Thu Dec 22, 2011 11:49 am

Re: New voltage measurements.

Post by techman » Fri Mar 23, 2012 6:17 pm

I would wind about 500-1000 turns of the 25 ga and see what voltage you get with a metal core. It should be pretty good.

Electric hobbyist
Posts: 9
Joined: Tue Mar 13, 2012 10:49 pm

Re: New voltage measurements.

Post by Electric hobbyist » Sun Mar 25, 2012 10:14 pm

If I were to use, say, 15 gauge wire, how many turns would I need with that?

techman
Site Admin
Posts: 1329
Joined: Thu Dec 22, 2011 11:49 am

Re: New voltage measurements.

Post by techman » Mon Mar 26, 2012 6:47 am

You can precisely calculate the number of turns per coil based on magnetic flux, coil size, magnet size, wire gauge, distance between magnet and coil, coil core material and density, and a bunch of other things, which give me a headache to understand.

Most generator DIYers use trial and error. Based on my own experience, more windings = more voltage. Simple.

Larger diameter wire = more amps capability. Simple.

Now, take whatever wire you want to use, and fill up the spool you have on hand. If it is larger ga wire, say 14 ga, then about 150 turns. But thinner wire and you can go with more turns. It is not easy to be precise. With your 15 ga, maybe 200 - 300 turns. See what it brings.

Make one coil and measure its output. Then multiply it by the number of coils you are going to have to get total output voltage. Again, remember to use a metal core in the coils.

Dont worry about high voltages. The 12 volt lead acid battery will bring the voltage down itself. I work with the Bedini Generator (SSG) motor and we use 800 turns of 18 ga wire. This thing puts out 200 volt spikes into the battery with no harm. On the contrary, it breaks up the sulfation on the plates of the battery, restoring it to like new condition.

Post Reply