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So the wife and I recently bought a small, remote cabin that’s off the grid. It has a small creek that runs through the property and I think I could use it to power a small turbine that would provide power. I found a you tube video where a guy uses a bunch of old parts, including a car alternator to generate power. His setup provides about 40v and he uses this to charge batteries that in turn provide DC power to run things like lights. I think I can go one better and use a transformer to up the voltage to 120v AC. Two questions:

1. How fast does a car alternator need to spin to get to 50v output? The transformer I found on line can up that input voltage to 110/120.
2. Does a car alternator generate at 60hz so that this setup could conceivably convert and power things like induction motors (for a refrigerator for example) or a tv/dvd player?

The cabin is wired so that a regular gas powered generator plugs in and runs the whole thing. I’m looking for something that’ll do that without the need for gasoline or the noise.
 

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Alternators are much more efficient than the old generators. Even lowish RPMs will do the trick, think Idle speed in a car, its charging!
Alternators are DC, so theres no Hz involved, just current & voltage.
If you wanted to transform you'd need a mechanical inverter to get A/C then transform & rectify back to D/C, with all the energy losses & noise that would create.
WE did this & after some false starts & mods we went with a 24V system because at the time most RV''s were 24v & truck batteries were easy & comparatively cheap.
Put Zener Diodes in to dump excess voltage to ground & current regulators to prevent frying your batteries as well.
Much more discussion & some good links here:
As you know I'm a fan of Micro/pico HEP.
more genny/alternator info here:
How Alternators Work
 

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Look at drawings of old mills and you'll see that there is always a diverter channel to a deep trough, running either from a reliable stream or from depth in a mill pond. It is much easier to get water in a narrow channel to slowly turn a large diameter wheel with paddles that nearly obstruct the flow path slowly with plenty of torque and then gear up the shaft speed than it is to get a small wheel to reliably turn fast with any torque.
 

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I absolutely agree that some kind of header pond & sluceway is the best setup, regardless of the actual genny power input.
Our biggest problem was debris like large numbers of leaves in the fall. We diverted off to the side of the stream, & put n angled barrier right before the inlet. The leaves would divert & run downstream, but the water would do the "U" & run into the offset area. Our stream was in a hilly area so we simply ran the pipe with minimal pitch, then sharply went to a 45° down angle, then a 60° one.(This saved wear on the elbow, & reduced resistance in the flow.), once through the vertical drop (about 8' or so.) it simply went back into the stream lower down.

Also google "micro home made pelton wheel". Lots of clever trick revealed by several different setups.
 

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The Pelton turbine for power would be the way to go IMO, less construction problems. Your own mini Hydro-Electric plant.:)
Could also consider a Hydraulic Ram to pump water up to a catchment tank. Found a late19thC book in the State Library outlining design details for a friend who was contemplating building one.
There was one with a cast iron dome at Calwich Abbey on the Dove in the UK, still working 24/7 in the 1960's.
 

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We tried that first, the down flow was more powerful than the deflection.
That's why we had to get the stuff further away by "bouncing" it off the pressure wave. By the time it had come back to the inlet side it was downstream so it didn't matter any more.
 

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An automotive alternator has the rectifier and field regulator built in. To try to bypass the recifier, would need an alternative way of regulating the rotor field.

The other end of this is an inverter. How many watts are needed?

A homespun AC system sounds romantic, but it's also a good way to fry modern electronic devices.
 
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