Power generation from Stream- HELP PLEASE

[MeSoNaM]

Which type alternator and Trubine should i go with?

As per my site survey... i got following data

Head=15 meter and more    or        49 feet
Flow of stream is about    12 gallons  per hour
Pipe length my be about 120m or 393 feet

Sonam
From Bhutan

[hydrosun]

I hope you mean 12 gallons per minute. That would work on a small pelton turbine coupled to a slow speed alternator (maybe 1200 rpm for 12 volts) 

If you only have 12 gallons per hour you would need to either store and dump the water for a shorter period of time or be able to downsize the generator. Years ago I used a 3 watt bicycle generator with a metal shaped into many buckets pressed onto the end to produce a trickle of power.
Chris

[MeSoNaM]

SORRY.... I MEAN 12 gallons  per SECOND or more

[hydrosun]

Sonam
that's completely different.  For that kind of flow you could use  a crossflow  turbine. The output of a 50% efficient system would be over 3500 watts. You would want to use an 8 inch or larger pipe to keep the pressure loss low. The alternator needed depends on what you intend to do with the power. If you intend to produce stand alone AC to your loads without batteries you could use an induction motor with appropriate capacitors.  I'd suggest getting more detailed answers from the microhydro forum.  Nando used to answer some questions on this website but now I only see his replies at tech.groups.yahoo.com/group/microhydro  He has the experience to better guide you. I don't have the experience with your type of site.
Chris

[MeSoNaM]

Thank You hydrosun....
i thinking to use AC power for lighting without batteries... but don't hav clear idea in generator to go about....
ya..i try the yahoo site...thanks