Racerdabba

guys please help me on this one. i am a final year btech student and we need a low speed dynamo/alternator capable of charging a battery and running a few appliances, deliverin 12v. as far, we havent found any that can provide gud power at 200 rpms. so i thought of rewinding a bike alternator to do the job. experts please guide me. is it possible? if yes wats the procedure to be followed?


P.S- Mods, please move it to approprite section if it doesnt belong here.

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sunilg

Query approved.

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msatheesh76

The alternator set up on a two wheeler is a built in set-up, you can not bring it out for your project. If you need to do this, it needs a very complicated mod.

My thought is, you can go for some other dynamo and boost your input rotation with some other mechanism like Gear wheels.

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Racerdabba

thanx for the reply buddy but i've already thought on those lines. and at any cost i cant boost rotational speeds from 200 to some 3000 for alternators. gearing wl allow it but my application doesnt have so much torque. as for the mod to bring out a bike alternator, its possible and do able. all i need to know is about the rewinding.

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NANOtechnology

dude, why dont you go for a car alternator?
it is bigger, but can produce great amount of current on lower revs..
current bike gives 12.3 volts of AC at 1.4k rpm..
car alternator will do the job i suppose.
as cars run on even lower rpm's and need 3-4 times more current.

besides why don't you wind the coil with thinner wire but a lot more number of turns?
it will result in great voltages, but the amps will be very low.
it will do the job regarding a project.

go to any auto electrician and check yourself the voltages at low rpm's.
i bet they will have loads of car alternators in junk which they can sell you dirt cheap.

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pavanchirmade

The kind of rewind job depends on what your need is. If you need just 12V and heavy current then you need to rewind with thicker wire and as many turns as possible. If your application is voltage intensive then you need to get thinner wire and rewind to a crazy number of turns.

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Racerdabba

AFAIK car alternators have small dia pulleys in comparison to crankshaft pulley and so they run faster compared to crank. if crank spins at 900, the alternator wl b doing about 1100. way too large for me.

guys pls tell me if using thin wire and more turns wl let me produce 14v and decent current at 200 rpms.

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Dessfox

Theoretically speaking, even if rewinding with thin wires and more turns helped, in order to get get 14 volt at 200 RPM on a bike alternator, the amount of wire and turns required would be so much that it wont physically fit in the stator/system any more.