a modern car alternator has only a pair of brushes on non-commutated slip rings. The typical lifetime in a car environment is 100-150,000 miles which equates to 3-5,000 hours of operation. The brushes carry only exicitation current for output regulation. The Rpms should be at least 2,000 but the higher the better as you can make more power.Much over 8,000 will result in increased wear on brushes and bearings. Why dont you do a positive displacement motor? That will be much more efficient than a hydrokinetic motor with water splashing off. Tom Kasmer
--- Hugh Piggott <[EMAIL PROTECTED]> wrote: > hi > > I'm not quite sure about how to calculate psi or > the kw per > >hour/day that could be generated from what we've > got, only that the > >spigot out of which we got 5 gpm is fairly close to > the ground level > >and distance from source that the proposed location > for the > >equipment would be. > > you will need to provide information about the head > of water > (pressure/height) before we can assess the > size/speed. > > > > > We had envisioned that whatever setup we decided > on, it would be > >propelled by water from a standard household pvc > pipe. Ideally, we'd > >like to build everything from scratch. We have > friends who do sheet > >metal work, so we'd be able to rig up a wheel (say, > by welding > >blades to a bike wheel). We figured that our > proposed setup would > >use a wheel which would spin a car alternator which > would send a dc > >charge straight to the batteries. > > A car alternator is cheap and can work after a > fashion but is not > efficient and will need new brushes pretty often. > Why not build the > alternator from scratch using a design like I do for > wind turbines? > YOu can see examples on my web pages. the main cost > is the magnets, > but a small one running fast would work with less > than 100 dollars > worth of magnets. > > I have designed some hydros like this but never > built one myself yet. > > As for the wheel it would be clever to use a proper > pelton runner (if > you have the head for it). you can buy them pretty > cheaply or make > them with plastic buckets that you can surely buy > from someone here > at low cost. > > > > > We'd like to do something as cheaply as > possible, but obviously a > >scratch-built unit is going to suffer a lot of > mechanical loss that > >a pre-fab unit wouldn't have. > > The pipe is likely to be a big cost. it does not > make sense to go > cheap on the turbine if it produces little or no > power. > > > > > If someone has attempted such a project, or > knows what the issues > >are that we need to resolve (gearing ratios between > wheel and > >alternator, how fast an alternator needs to spin in > order to > >generate current, how to avoid ovecharging, etc.), > it would be much > >appreciated. > > I can help with all that, given more data. > > > > > -- > Hugh > > Scoraig Wind Electric > http://www.scoraigwind.co.uk/ > > > > ------------------------ 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/
