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Forum Index : Windmills : alternator voltages

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windtinker
Newbie

Joined: 16/01/2012
Location: New Zealand
Posts: 38
Posted: 01:41am 18 Jan 2012
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Hi
I was wondering if you have a 12 volt alternator if you hookup 48volts to the feild coils weather you can use lower rpm to produce 12 volt output.
I trying to gear a car alternator for a project, just seeing if theres a way to get lower rpms.

Thanks
windtinker
 
Gizmo

Admin Group

Joined: 05/06/2004
Location: Australia
Posts: 5111
Posted: 02:11am 18 Jan 2012
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You would tend to cook it I think.

Have a look at Matts projects, he did a alternator conversion, I think it was a 24v alternator and he fitted magnets to the armature.

http://www.thebackshed.com/Windmill/articles/MattLyons.asp

Glenn
The best time to plant a tree was twenty years ago, the second best time is right now.
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Warpspeed
Guru

Joined: 09/08/2007
Location: Australia
Posts: 4406
Posted: 03:40am 18 Jan 2012
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  windtinker said   Hi
I was wondering if you have a 12 volt alternator if you hookup 48volts to the feild coils weather you can use lower rpm to produce 12 volt output.
I trying to gear a car alternator for a project, just seeing if theres a way to get lower rpms.

Thanks
windtinker


No, magnetic saturation will defeat you.

However, if it produces 12 volts at 1,500 alternator rpm, with full field excitation, it will produce 48 volts at 6,000 rpm with full field excitation.

A 12v alternator will work fine at 48 volts, but it will need to spin a lot faster before you start to see any charging current.
While that may be practical if driven by some sort of engine, it becomes impractically fast and very inefficient for a wind turbine.
Edited by Warpspeed 2012-01-19
Cheers,  Tony.
 
windtinker
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Joined: 16/01/2012
Location: New Zealand
Posts: 38
Posted: 03:50am 22 Jan 2012
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Hi thanks for the replies. Its more tinkering than anything.
I've taking to bits one and tried some experiments, pulsating the field coil, with the rotor stationary it got upto 17volt for 2.5amp in the field. Would this produce power if the rotor was spinning or transformer from the battery back again.
Cheers
 
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