I'd guess that a car alternator would be serious overkill... too much windage and bearing loss, and even the field excitation would exhaust the peddler pretty quick. A smaller permanent-magnet motor would probably be a better match at this power level. Maybe
A motorcycle generator (PM rotating field)
An auto window-winder motor. New ones are super-magnet field things
A PM stepper motor, maybe from an old printer. Maybe several.
John
Nepal produces 81% of it's electricity from Hydro. Why not use it? Why go to all the trouble of manually generating a few watts to power a WiFi terminal?
Also when the sun doesn't shine, Monsoon rains are pouring down, funnel it into a small hydro generator for recharging the batteries.
Jim Thompson wrote in news: snipped-for-privacy@4ax.com:
Jim,
As unbelievable as it sounds, my boss told me this when I was working as a truck and heavy equiment mechanic. The next time I had an opportunity, I tried it on a CCC (Crane Carrier Co.) truck. This was a older version of the Redi-Mix truck pictured at
Anyway, the truck featured a Cummins 6 cylinder diesel engine similar to the GMC 671 series diesel engine. It had similar displacement, (about 71 cu inches per cylinder), and 6 cylinders. Of course the Cummins did not have a supercharger like the GMC, but since the GMC is a 2 cycle diesel, it has to have a supercharger. Anyway the engine was idling and when I applied 12 volts to the rotor of the alternator with it's output shunted directly to ground, the engine stalled and stopped almost as if one had shut off the fuel. Yes, the fuel shutoff valve was bypassed just to make sure there was no doubt that this was NOT a rigged demo.
If you want another unbelieveable true story, let me tell you about the time I fired up a GMC engine in a International truck and it started running backwards. Smoke was pouring out the intake and it lacked all manner of power. Reverse was forward and forward gear was reverse. Once I figured out what was going on, I shut it off, restarted and everything was fine.
r-- Nothing beats the bandwidth of a station wagon filled with DLT tapes.
------------------ No power distribution wiring.
-------------------- Not bad, but it would take a lake. Not portable.
-Steve
-- -Steve Walz rstevew@armory.com ftp://ftp.armory.com/pub/user/rstevew Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!! http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public
-------------------- Why is this surprising?? You just invented an electric brake!
------------------- How was it running backwards? The 4-stroke cycle doesn't permit this! Sounds like an urban legend. Do you mean the starter turned it backwards, why was the bettery reversed?
-Steve
-- -Steve Walz rstevew@armory.com ftp://ftp.armory.com/pub/user/rstevew Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!! http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public
A *smaller* PM dc motor linked to a metal gearbox and a handcrank is the way to go. I recently tried this as a method of recharging NiMH batteries for my shortwave portable. My gearbox had plastic gears though, and they only lasted about 30 seconds before succumbing to the stress I was putting on them (which was backwards for the way they were designed to be used. I was using the big gear to drive the small gear, not the other way round.) For that 30 seconds though, it put out 500 mW at nearly 9V. Now if I just get off my butt and find some metal gears that fit that housing, I'll be set. If you are trying to charge a big battery, crank it for a longer period of time (or with several volunteers in succession.) A better idea would be to hook it up to a bicycle, since the muscles in the legs are more suited to this type of thing. That would be less portable though (which was one of my major concerns.)
Dave snipped-for-privacy@hotmail.com
That one went over my head
This happened to a friend of mine on a two stroke diesel after a particularly poor gear change on a steep hill. He doubled the cluth into first gear and when he let the clutch up the wagon went backwards. To make matters worse the air intake was in the engine compartment between the seats, within a second or two the cab was completely full of smoke. It's a good 20 years ago or so.
X-No-Archive: yes "Mjolinor" wrote : "Roger Gt" wrote : > A prime example of true British Thinking! : > Cubic meters? How about cubic "cubits?" : : That one went over my head
A Cubit is about 18 inches, so a cubic Cubit would be about a quarter the volume of a cubic meter. (See conversions) Not likely a single ox would produce a large volume of Methane gas what you could meter in cu Meters!
Looses a lot in translation!
It certainly does because that one went over my head as well.
I would have thought that as it was cubic metres initially then it would be more correct to quote a cubit to be slightly over 457 mm. I suspect the volume would be the same whether measured in cubic metres or cubic cubits or maybe some other antiquated units like cubic inches, cubic feet or maybe cubic furlongs is to your taste. :)
Using the manure as well you get the equivalent to about 50 gallons of petrol per year in methane from one cow. The gaseous emmisions will light a
75 watt light bulb continuously. If the Internet is to be believed :)"R. Steve Walz" wrote in news: snipped-for-privacy@armory.com:
It is not an urban legend. I was there. I started it, I tried to drive it. The year was circa 1975. It was a cold day with snow on the ground. The foremans last name was Fang. Had efficiency experts come there once. They worked for a company called Proudfoot. No urban legend here.
All of the GMC engines that I have ever worked with are 2 cycle engines. That includes their very large locomotive and marine engines. (Yes I worked for Electro-motive for a while as a Locomotive Electrician) That also includes their 53 series engine which boasts 53 cubic inches displacement per cylinder. That little workhorse is pretty amazing. That particular engine was used in a piece of equiment commonly called a Straddle-Buggy. Made by Hi-Jack? Corp who has offices in Hazel Crest IL. The tires used on that bit of equiment were used commercial aircraft tires. I digress, but GM's supercharged and turbocharged (yes, both at once) 6 and 8 cylinder models are rather special too.
The engine in question was a GMC engine. A series 871 if memory serves me right. If it wasn't a 871 it was a 671. (we had 1671 series as well..16 cylinders at 71 cubic inches per cylinder. See Euclid R-50.) What happened was that the starter was not engaged for the proper length of time and the resultant "kickback" had enough energy to start the engine rotating and firing backwards. This mode of operation is not recommended due to the lack of oil pressure. Yes, I noticed that there was no oil pressure on the gauge, but since so many things didn't work when it was unknowingly run backwards, I figured that is why it was brought to the shop. It wasn't until I tried to move it and the vehicle travelled the opposite direction of what was clearly marked on the transmission shift pattern plate, that I realized what had happened. That was a few careers ago. Many things have changed since then.
r-- Nothing beats the bandwidth of a station wagon filled with DLT tapes.
Thats lots more than a human can produce though.
True about the not being portable but micro hydro will work on runoff. (works here. in winter)
Still, a major installation compared to a bicycle. and definitely not "on demand"
Fritz
Quite possible, in fact, I saw one today in an environmental education site. They had an older DC-generator resting with a small pully on the back wheel tire, plus what looked like a much smaller generator a little bit behind (maybe for the field current?). Very modest peddling already lighted a 20W energy-savings lamp (small fluorescent), fanatical peddling lighted a 500W halogen builder's lamp. A trained cyclist surely could supply 50W for a hour at least. And I think a modern AC generator has higher efficiency, plus voltage regulation built-in. The bicycle wheel was 24 inches maximum (might have been smaller), the pully on the generator shaft looked like made from brass about 4 cm diameter. The tire was slightly soft (not hard inflated). Is there enough wind there to build a small windgenerator with it as well? Maybe you can build it so that the generator can be used for both.
Mat Nieuwenhoven
X-No-Archive: yes
"Mjolinor" wrote : "Roger Gt" wrote : > "Mjolinor" wrote : > : "Roger Gt" wrote
: > : > "A prime example of true British Thinking!"
: > : > Cubic meters? How about cubic "cubits?" : > : That one went over my head : > A Cubit is about 18 inches, so a cubic Cubit would be about a : > quarter the volume of a cubic meter. (See conversions) Not : > likely a single ox would produce a large volume of Methane gas : > what you could meter in cu Meters! : >
: > Looses a lot in translation! : : It certainly does because that one went over my head as well. : : I would have thought that as it was cubic meters initially then it would be : more correct to quote a cubit to be slightly over 457 mm. I suspect the : volume would be the same whether measured in cubic meters or cubic cubits or : maybe some other antiquated units like cubic inches, cubic feet or maybe : cubic furlongs is to your taste. :)
A meter is 39.3700787 inch so 18 about inches is close enough for government work! Cubic Chains "Or" Fathoms, I use them all! They are all valid. Like "Stones" in England!
: Using the manure as well you get the equivalent to about 50 gallons of : petrol per year in methane from one cow. The gaseous emissions will light a : 75 watt light bulb continuously. If the Internet is to be believed :) :
The point was that the "British Thinking" is over stated in grand terms and about manure!
I see that implied humor does not play well on the news group unless you add (:>) to every instance! So the reader knows to expect some obscure humor or innuendo!
I still don't see it :)
Implied humour worked fine for me in all the posts.
As a user of "stones" I find it kind of hard to measure volume with it.
site.
wheel
20Whour
(might
There has been much noise and warm air about micro generation techniques. Little useful will come from this speculation before the OP states what kind of load and duty cycle he needs. Once he defines his needs, then he might also disclose his assets; available money & labor & time, geography, local fuel assets and local weather. Even local social customs may be a huge factor; for instance, possibly one of those Sherpa guys, who can climb to
20k feet without breathing heavy, might be able to put out prodgious power from a bicycle generator at 8k feet. OTOH, he may be prevented from doing this by viewing this as a less than honorable task for a Sherpa man.Ed
On Sat, 29 May 2004 07:59:43 -0700, Jim Thompson wrote:
I built one of these as a prototype for a cycling club training device. It worked very well. The guts to it was a frame that a
10-speed bike could rest in, and place the back wheel over a heavy 4 or 5 inch diameter SOLID cylinder, that was pulley coupled to an ordinary automobile alternator. The cylinder provided inertia to simulate cyclist mass, and to minimize effort during pedal pushes. I used some programmable devices to vary the load to simulate wind, hills etc. For reasonably skillful cyclists (or for high speed rpm's on the back wheel), you don't even need a frame, the bicycle will balance naturally. Even better is if you couple an additional cylinder from the back cylinder to the front bike wheel, and you can "ride" the bicycle free of any frame. If I remember correctly, it is not unreasonable for a cyclist that is in good shape to do about 1/4 HP for about an hour or two, with peaks up to 1 HP. I never did it, but I considered running a TV off the alternator, and the cyclist would watch a movie. If he slacked, the TV would dim. If he was energetic, a low capacity battery would be connected, so that the excess power would allow him some rest intervals. If a cyclist ran 1/4 HP (about 15-16 Amps at 12 volts DC), he could fully charge a reasonable car battery (70 AH) in about 4 to 5 hours. He might need a second person to substitute when he got tired. In a remote area, this would power transcievers, TV's, cell phone chargers and other 'useful' devices, and would be far faster and far cheaper than solar cells. Repair and replacement would be low-tech, just grab another alternator and belt from another car. Practically everything you need for repair or building is available from typical cars. In my case, the trickiest item was the heavy cylinder(s) needed to simulate "the road". It is definitely "do-able", fairly easy to make, and performs well. Make sure that a decent 12 volt fan is used to cool the cyclist, along with copious amounts of water!-Paul
.............................................................. Paul Somewhere in the Nova Scotia fog ANTISPAM - Please remove the m's in my email address
----------- You mean an eighth.
-Steve
-- -Steve Walz rstevew@armory.com ftp://ftp.armory.com/pub/user/rstevew Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!! http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public
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