Thanks for the reply. 50gpm is the minimum flow even in times of drought.
Several formulas on the net showed we could expect to produce about 20 watts w/ 50gpm and 4-5' head. This equates to 1.6 amps at 12 volts. I figured 1-1.5 just to be realistic. Thanks for the advice on PM motors, I'll check them out. Since posting I found that Delco has come out with brushless alternators available in 12, 24 and 48 volts. I'm waiting for a quote on one now, rewound to produce at lower RPM. I expect it's going to be too pricey. Thanks again. --- In [email protected], tom kasmer <[EMAIL PROTECTED]> wrote: > > > my experience witn GM alternators is that the brushes > will last > about 150,000 miles + or -. That is a half year of > steady driving. The alternator is subjected to > underhood temperature extreemes and wild > accelerations. In an outdoor enclosed housing, > running at a fairly constant speed, you might get a > year of 24/7. > Your 1-1.5 amps sounds low. How did you get that > number? As far as PM generators, any PM motor will > work nicely as a generator. > 4 feet of head is only 2 psi of pressure. How much > total flow > does the creek have worst case drought time? Is that > the 50 gpm number? If you are limited to this level of > power, that is about > 20 watts best case with an automotive generator. You > might better spend your budget on a photovoltaic array > and settle for > daylight only solar power with less hassle. Im not an > expert in microhydro power so others may do better. > Tom Kasmer > > --- williameverettstone <[EMAIL PROTECTED]> wrote: > > > Hi All, > > I have a situation with minimum 50gpm flow year > > round (I have been > > measuring for 5 years, through drought and different > > seasons). > > > > My wife and I are planning to rebuild the remnants > > of a small dam on > > the creek which would provide about 4' head. We > > estimate we could > > generate 1 to 1.5 amps here. > > > > We are on a budget, and a prebuilt micro hydro unit > > is out of the > > question, at least the ones I've seen so far ($1,000 > > and up). > > > > If we were to use an off the shelf auto/truck > > alternator w/ brushes, > > how long can we expect the brushes to last running > > 24/7? Are PM > > alternators available, and how pricey are they? > > > > My second dilemma is predicting the best turbine > > type and size, and > > pulley ratio to obtain the highest RPM at the > > alternator with the > > available water flow. Is there a method to help make > > these decisions? > > If we fabricate some sort of squirrel cage type > > turbine, how do I > > decide the optimum radius of the unit? > > > > Thanks so much for any help! > > Bill > > > > > > > > > > > > > > > ------------------------ Yahoo! Groups Sponsor --------------------~--> Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/FGYolB/TM --------------------------------------------------------------------~-> Does your company feature in the microhydro business directory at http://microhydropower.net/directory ? If not, please register free of charge and be exposed to the microhydro community world wide! NOTE: The advertisements in this email are added by Yahoogroups who provides us with free email group services. The microhydro-group does not endorse products or support the advertisements in any way. More information on micro hydropower at http://microhydropower.net To unsubscribe: send empty message to [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/microhydro/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
