Car Alternator as Human Powered Generator

The Short answer is NO! Takes about one horse power and about

2000 RPM... Not something most men can do for any length of time.

Wind mill maybe?

------------------- Nonsense, just turn down the field current, or use several people.

-Steve

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Do the experiment! :-) Take a bike, and take the tire off the back wheel, and use it as a pulley. Run a belt around it and the generator /alternator pulley, and use an ordinary 12V battery/regulator. Then pump away! A man can easily generate 1 HP for awhile, and if you're in really good shape, you can pedal an airplane across the English Channel. :-)

In fact, I seem to remember doing an experiment in HS physics class, where they went to a 2-flight stairwell and had a couple of volunteer boys run up it as fast as they could. They timed it, and calculated the kinetic energy expended, and some guys made almost .75 hp. So I think any old ordinary person on a bike could make enough electricity to run a radio or something. In fact, in the Science Musem in St. Paul, MN, they used to (maybe still do) have setups exactly like that, with a TV right in front of you and I think meters.

As to RPM, I really don't think it matters that much, as long as it's more than some threshold value. I can visualize a belt around a bike wheel driving a "standard" alternator, and I can almost hear it whirring. It just intuitively, to me, seems to "automatically" run at the right speed. And you can get 10- and more- speed bikes!

Good Luck! Rich

How about animals and gears?

Bill

been there, done that. it will be a long uphill stretch of road to pedal though. For a rikshaw jock no problem. They run entire sound stages at alternative energy shows from banks of bicycles. Ganging up is definitely a plus. Put a rheostat on the field so you can adjust. put it in the hotel lobby so the fat tourists can work out some.

>

Oxen or other animals going in a circle with a drive to the alternator.

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This site may be of interest...

Some info on using a car alternator here.

The main problem is that you need 800 to 1000 rpm at least to drive a car alternator (Note gearing up in photo of the windmill on the page above). A human works best at

Hi Robin,

I think you would be better off with generators with permanent magnets and of a smaller size (or even DC-motors in reverse?), like some slightly owergrown bicycle dynamos.

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Absolutely! I worked on the electronics for an exercise bicycle that used an alternator as a variable physical load AND provided the power for the circuits.

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

links

Very interesting. It looks like the answer to Robin's question is yes.

Bob

with

powered

How

is

Hasn't Lee Felsenstein (of Homebrew Computer Club fame) already done this for a village in Laos? Perhaps you can contact him, or any number of folks who worked on this

Alternately, you could contact Jon Katz, who has set up homebrew hydro power generation in the Domican Republic using a three phase motor, a controller, and some space heaters:

I suspect you can contact Jon at his Cornell email address for more information.

Anyway, good luck with your project.

Regards, Bob Monsen

X-No-Archive: yes "Bill" wrote : "Roger Gt" wrote : > "Robin" wrote

: > : Hello All, : > : : > : I do some volunteer work that provides rural : > : villagers in Nepal with WiFi communication : > : (See

if you are : > : interested). As part of this work, we need : > : to develop a human powered generator to charge : > : our solar batteries when there is no sun for : > : months on end. Is a car alternator and a : > : bicycle a possibility? How much current/voltage : > : does a typical alternator produce and what RPM is : > : necessary? These are both readily available : > : in Nepal, so they would be idea. Thanks very much. : > : Robin Shields : >

: > The Short answer is NO! Takes about one horse power and about : > 2000 RPM... Not something most men can do for any length of time. : >

: > Wind mill maybe? : >

: How about animals and gears? Bill

Messy, But an Ox on a "go around" pulling an arm could be geared up to do it. Someone would need to clean up after the ox though! That would require an attendant to care for the ox. The typical alternator from a small car or pickup will produce up to about 50 amperes at full rpm, but it also draws power from the battery for the field current. So disconnect it when not in use!

The gear ratio is really big. Lets see, an Ox walking around once ever 15 seconds, to get 2000 rpm. Gear up is 8000/1. It's doable but messy.

1. First you need a 6 foot diameter pulley mounted on the center of the "go-Around" ( Nominal 4RPM) a belt drives a 2 inch pulley gets you a 36/1 ratio to provide (144RPM), then the 2 inch pulley shaft drives a 30 inch pulley, this belt drives a 2 inch pulley on the alternator at 2150RPM. Gee, only two stages!

I'll leave the simple mechanics up to your available materials.... and ingenuity!

If the oz moves slower you need more gear up! A 36 inch secondary pulley will allow the Ox to go around in 20 seconds! (3RPM)

Gee, why do villagers need Wifi? Can't they just talk to each other? My fathers farm doesn't have Wifi. No one misses it! The Cows least of all! They just kick a soccer ball around the pasture for entertainment!

Hi!

Could you not just put the Ox in a field to graze, stick a pipe up it's rear, collect the methane, then use that to drive an engine, or burn it to generate steam to power a turbine to run the alternator!

I'm not too sure of the Cubic meters per hour one average size Ox produces tho.....

:-)

Yours, Mark.

Roger Gt wrote:

X-No-Archive: yes A prime example of true British Thinking! Cubic meters? How about cubic "cubits?" I'll let you insert the tube! (Top posted in response to a TOP POSTER!)

"Mark (UK)" wrote : Hi! : Could you not just put the Ox in a field to graze, stick a pipe up it's : rear, collect the methane, then use that to drive an engine, or burn it : to generate steam to power a turbine to run the alternator! : : I'm not too sure of the Cubic meters per hour one average size Ox : produces tho..... : :-) : Yours, Mark.

: > : How about animals and gears? Bill : >

: > Messy, But an Ox on a "go around" pulling an arm could be geared : > up to do it. Someone would need to clean up after the ox though! : > That would require an attendant to care for the ox. : > The typical alternator from a small car or pickup will produce up : > to about 50 amperes at full rpm, but it also draws power from the : > battery for the field current. So disconnect it when not in use! : >

: > The gear ratio is really big. Lets see, an Ox walking around once : > ever 15 seconds, to get 2000 rpm. Gear up is 8000/1. It's doable : > but messy. : >

: > 1. First you need a 6 foot diameter pulley mounted on the center : > of the "go-Around" ( Nominal 4RPM) a belt drives a 2 inch pulley : > gets you a 36/1 ratio to provide (144RPM), then the 2 inch pulley : > shaft drives a 30 inch pulley, this belt drives a 2 inch pulley on : > the alternator at 2150RPM. Gee, only two stages! : >

: > I'll leave the simple mechanics up to your available materials.... : > and ingenuity! : >

: > If the oz moves slower you need more gear up! A 36 inch secondary : > pulley will allow the Ox to go around in 20 seconds! (3RPM) : >

: > Gee, why do villagers need Wifi? Can't they just talk to each : > other? My fathers farm doesn't have Wifi. No one misses it! The : > Cows least of all! They just kick a soccer ball around the : > pasture for entertainment! : >

: >

: >

: >

:

snipped-for-privacy@HimalayanHandicraft.org (Robin) wrote in news: snipped-for-privacy@posting.google.com:

It takes a fair amount of power to run an alternator at full output. If you take a 50 amp alternator, ground the output and fully energize the rotor coil, ir will stall out a large 6 cylinder Cummins diesel engine. As a matter of fact it will stall it out so quickly, that a bystander would say that you shut the engine off.

r

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Don't they have wind in that part of the world? If you must pedal, I'd think about a lower RPM generator so you don't use up all the energy overcoming mechanical losses. mike

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Now mention that it requires a battery in good shape (or a live electrical outlet) to boot it. An old '50s style PM automotive generator doesn't need an electrical source for its field.

Where in the world did you get that idea? Must be some weenie engine!

12V at 50A is only 600W, even presuming something like 50% efficiency that's only 1.6hp.

IIRC a typical automotive 50A alternator takes about 6hp input at (alternator) 14,000RPM.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

A GM alternator doesn't either, to get it started, then it requires a minimum load, or it goes over-voltage. GM calls that load "daylight headlights" ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.