24 volt pmg

[corny]

i have access to brake rotors etc., but i was wondering if i built a larger rotor, would the larger diameter be beneficial to this project? i am running a 24 volt system at present, all the water turbine projects seem to be 12 volt what would i need to change? how many magnets and what length and size wire would be required? any and all advice will be appreciated

[Flux]

If you want advice you will have to supply information. How can anyone possibly answer this.

What speed? what is the power out of your turbine? no chance without these basics, more wouldn't hurt.

Flux

[corny]

yes i'll try not to be so vague, i was thinking along the lines of a banki style turbine. i saw the write up on scott's dam, where he constructed a small hydro unit in this fashion. it's the first page that pops up when i hit otherpower in my bookmarks. i live about ten miles from the closest power line, phone and computer are by bag phone, heating is outside wood boiler and kitchen barrel stove, electricity comes from a diesel generator to a trace 4024 inverter/charger also a couple of windmills. hydro would be a beautiful thing if i could figure it out. my creek is about 12'-18' wide and only 2'-3' in the deepest areas. it is not very fast maybe 2mph. i figure the most head i could achieve would be about 4'. i am trying to figure a few things out before i get started, maybe it wouldn't be feasible, i don't know. at this point i can't get an accurate measurement as in the spring the creek is ten feet wider and much faster and deeper this will continue for a few more weeks before things settle down. the hydro plant that scott built has 12" dia. side runners and 10" long vanes, would 24" diameter runners with 20" vanes make a considerable difference? the rotor are 11" dia. with 12 magnets per rotor, does the number of magnets or the diameter make a difference? the stator has nine coils of 125 windings of #17 wire are more windings an advantage? would it make any sense to incorporate a shaft through the center with pillow block bearings on each end and add another rotor/stator setup on the other side? am i lost or is there hope? corny  

[wpowokal]

Corny, I would not see it as a lost cause as even a small wattage 24/7 adds up to a lot.

Do you have permission to alter this water way or perhaps permission is not required.

How far from proposed hydro to batteries?

You mentioned increased flow in spring, is this going to cause dificulties in mounting the unit, ie. is it likley to be submerged?

allan down under

[Flux]

You seem to have unlimited flow so if you can get a 4 ft head then you can do something useful.

Until you sort the water supply issue and settle on your turbine you can't really make many decisions on the alternator.

I think you can do something useful on the lines of Scott's turbine. Somehow I suspect they haven't got the nozzle right or the effective head is lower than suspected, I would have thought that a turbine rotor 4" wide would have managed their flow. If you can feed a 12" wide Banki properly at 4ft head I think it would take a considerably larger alternator.

The alternator needs to be big because of the low speed. The larger the disc diameter the more magnets you can mount on it and the more you can squeeze out. I wouldn't stack axially with more discs and stators until you have exhausted the diameter increase option. Just increase turns and reduce wire size to convert to 24v. The power you extract must be matched to the turbine. You are somewhere near right when you reduce the no load turbine speed to 50%, you may have to experiment with the exact point.

Flux