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/
