24 magnets

[srguy]

First of all I want to introduce my self my name is Francisco and I am looking in to RE and I found this web page interesting and informative and I love all the people that help each other here thank you all.

I was thinking of building a 9 coil 48v wind generator but instead of using the 12 1x2x.5 magnets i was thinking of using 24 2in x 1/2in x 1/2in Thick, Grade N45, Ni-Cu-Ni Plated Neodymium Block Magnet with a Pull Force: 55 lbs. I never have build one of this things and I was wondering if those magnets will work and produce electricity or will I have to change something to make it work. The magnet rotor will be 12" with the 24 magnets on it and just in case you are wondering why I want to use these magnets. Its the price they will cost me $2.19 a piece for a hundred vs $4.15 or $3.45 for a hundred for 2in x 1in x 1/2in Thick, Grade N42 magnets. Thank you all.

[mbohuntr]

In a couple of days, I should find the time for a coil test of those same magnets, I'll keep you posted, I'm just starting out too.

[MattM]

People have in a pinch used stacks of small magnets to form fewer, larger monolithic versions.

[Flux]

Yes you can use two magnets together with same polarity to replace a single bigger one. They will be a pain to mount as they will repel each other when you try to stick them down.

I personally would change the winding to 18 coils and make it 24 pole with each magnet spaced separately. This will need a redesign and your existing information on turns etc ( if you have any) won't apply.

Flux

[srguy]

I was thinking of making it exactly as the one in this site http://www.otherpower.com/turbineplans.html with the only exception of instead of using the 12 bigger magnets I was going to use the smaller magnets in a 24 evenly spaced setup but I was not sure it will work. The coils were going to be 15 AWG wire with 105 turns for 48v

[srguy]

I personally would change the winding to 18 coils and make it 24 pole with each magnet spaced separately. This will need a redesign and your existing information on turns etc ( if you have any) won't apply.

why wont it apply? does it have to do with the space in the middle of the coils?

why 18 coils? what gage wire?how many turns will it need?  will that still be a 48v setup? so many question that this is making me think.

[Flux]

If you copy the otherpower design and use 2 small magnets to replace the wider big ones it will work fine you just have to deal with the physical problem of placing magnets close together until the glue sets.

You will need a complete rethink to change it to 18 coils. If you were going it your own way with test coils and starting from scratch I would go the 18 coil route but as you are following the otherpower plan then stick to placing the 2 small magnets together for each pole. There is almost certainly going to be a loss in performance compared with 1" wide magnets but it will be perfectly ok. I suspect your 105 turns is on the low side for the 1" magnets and even lower for your magnets but I haven't gone back to the Otherpower article so don't take my word for it but I would have expected nearer 140 turns unless you are in a high wind area or want to trade low wind performance for better high wind results

Far easier to go that way than for me to redesign it with 18 coils and 24 poles. My quick calculations suggest that the 24 pole 18 coil winding works out a bit better but stick to tried and tested things.

Flux

[esc]

If the 2x1x.5 magnets are $4.15 each and the 2x.5x.5 are 2.19 each, you are paying more than half for half the magnet, so you are actually getting less magnet for your money.

Did I miss something?

[srguy]

well I was thinking more magnet more power because it will travel more times over the coils. hey mbohuntr when are you making your test and how are you going to have your setup?

[mbohuntr]

Just finished my semester finals, and should start up again soon. Does anyone have an idea of how many turns I need for these small magnets? Either a 3"x3" coil around a rotor, or a 1"x 2-1/2" coil on a flat stator (like you guys build.)?

[mbohuntr]

I tried 10 turns with a 3-1/2" square coil, and  the rotor in the center of the coil,  North poles at 0 and 180 deg., and south at 90, and 270deg. No apparent AC response, DC ammeter bouncing around at a couple of mA's. Same wire, 28 turns 1"x2-1/2" coil  rotor using 2 magnets, 180deg offset, opposite poles, same response... New magnet wire, N42 neos 2"x1/2x1/2 polarized thru thickness, 1/2" or less air gap. I sanded the wire ends as well before the test. WHAT am I missing here?  

[ghurd]

"WHAT am I missing here?"   Magnets!

And an undestanding of the coil size to magnet placement?  You don't give enough information to say anything else.

G-

[mbohuntr]

Ok... I will provide pics as soon as possible...

[srguy]

do you have a pics yet?