What's the best option for my magnets?

[Bobbyb]

Hello

I have 40 12mm x 6mm magnets.

For a dual; rotor system I made some test coils and my best result was 4 watts out of a +-110 turn .6mm wire coil at 100hz witch is 600rpm at the blade's

Since I will have 15 coil's (5 per faze) in the full stator I expect to get 60 watt's

This seems a little small for the amount of magnet

I calculated the power by multiplying. Is this right?

I'm thinking that it might be better to use the magnets for a motor conversion.

I've read that conversions give more power for the same magnet size but sinse I will still have to find a cheap motor what is the best option?

greatings,

Bobby

ps: If someone knows an existing genny (conversion or dual rotor) with my size magnets pleas let my know

[Flux]

Those magnets are tiny and far from a good choice for a dual rotor. As you say you will probably get more from a motor conversion. Even then I don't think you have enough to do anything very exciting.

Flux

[Bobbyb]

I'm not looking for kilowatts but from reading the board i expected to get 80 watts per cubic inch for a dual rotor genny

since i have 1.65 cubic inch I expected to get 130 watts

but thx for the quick reply

[Flux]

I wouldn't take those watts per cubic inch figures too seriously even in the normal regions they are almost guesswork. When you extrapolate to extremes then they are less than useful.

I just checked a few figures and with those magnets on a well designed 3ft machine you could probably get 120W but at a wind speed of about 30mph.

If you increase blade size to get more power in lower winds then you drop the operating speed and the power you can expect falls rapidly. You would need speed up around 1000rpm to get the 120W. That sort of speed is possible for small machines if you live in a high wind area with well made blades but the output in the lower winds will be small indeed. Scale badly affects electrical machines, small ones are always inefficient no matter how good the design.

For axial machines magnets smaller than 1" diameter are hardly worth considering unless you happen to have loads of them cheap.

Flux

[dinges]

I have used that size for a motor conversion; was originally a 130 W   3-phase motor. See this gallery for more information:

http://www.anotherpower.com/gallery/album49?page=1

I used 48 magnets, BTW.

Curves with output current and voltage can be found here:

http://www.anotherpower.com/gallery/dinges/130W_genny_graph_output_001

http://www.anotherpower.com/gallery/dinges/130W_genny_table_output

At ~1000 RPM I got out 134 W (@ 48 V); it translates to about 70 W/cubic inch of magnets.

Just to give you an idea on what to expect in a motorconversion...

[zubbly]

hello Bobbyb,

here is a motor i spotted on ebay.

http://cgi.ebay.com/BALDOR-INDUSTRIAL-MOTOR-M3538-1-2HP-1725-RPM-MOTOR_W0QQitemZ280118476902QQihZ018
QQcategoryZ42920QQrdZ1QQcmdZViewItem

i think this would be an excellent match for a first time conversion with the mags you have. do your best to use all the mags in the conversion.  expect 100-150 watt per cubic inch of mag material you have.

just gut instinct, use a 3 blade 5 foot prop, trs-7

zubbly

[Bobbyb]

That's a nice conversion dinges did u use the original windings?

That won't be a cheap solution zubbly (since I live in the Nederland's).

but thanks it gives me a good idea what to look for at the local serape yard