Author Topic: Bicycle Dynamo powered by model I.C. engine  (Read 13887 times)

Offline Stilldrillin

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Re: Bicycle Dynamo powered by model I.C. engine
« Reply #30 on: November 30, 2014, 09:05:12 AM »
Very well done, and shown, Brian! 

I've enjoyed following this whole, generator saga.  :praise2:

David D

David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline Brian Rupnow

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Re: Bicycle Dynamo powered by model I.C. engine
« Reply #31 on: November 30, 2014, 05:57:37 PM »
For what it's worth--after spending some time adjusting the carburetor, I ended up with the following results. The top engine rpm with no load on it is 1900 rpm. When the slack belt is in place, it puts enough frictional load on the engine that the rpm drops to 1780 rpm. When the belt is fully tightened and the generator is lighting the light very brightly (2.9 Volt bulb), the rpm drops off to 1467 rpm. The finished diameter of the driving and driven pulleys is 2.0" and 0.845", giving a ratio of 2.367:1----So, the dynamo is turning at 3472 rpm. That is without factoring in any belt slippage. If we allow 5% for belt slippage then the dynamo is turning at 3300 rpm, and that gets pretty darn close to the "best guess" calculation I had made originally, that based on a 28" diameter bicycle tire, with the "rub contact" diameter at 26" , the dynamo with a 1" friction wheel on it would be turning 3000 rpm. when the bicycle was going 10 miles per hour.

Offline Brian Rupnow

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Re: Bicycle Dynamo powered by model I.C. engine
« Reply #32 on: November 30, 2014, 11:47:48 PM »
--Back when I was a kid, a neighbor had a "wind charger" mounted on his garage. As I remember, it had 4 or 6 "blades" made out of old car license plates, and was about 30" overall diameter. The "blades" were attached to a center hub that was mounted on a car generator, and he must have had a voltage regulator wired into it somewhere. He used it to keep a spare battery charged up. That would have been in the 1950's. Then in the 1960's when they ran the hydro line into Kaminiskeg Lake near Barrys Bay I was in high school in Bancroft. I got a part time job with Ernie Byers, a local electrician, wiring and doing some plumbing in cottages in on the Lake. One place sticks in my mind, because it had a fast flowing stream coming down the hill from the northwest side, right beside his cottage. He must have been a pretty resourceful guy, because he had a Pelton wheel in the stream, hooked up to a car alternator and had the whole cottage wired for 12 volt electric lights. One of the funny/crazy memories I have from that time---Ernie had a little wee car, I think it was a Mini Cooper or an Austin Mini. We went to the hardware store in Bancroft and picked up six 10 foot lengths of 1/2" copper pipe to take up to Kaminiskeg. He didn't have any roof racks, so he had me roll down the passenger window and stick my arm out the window and hang onto the pipes. They didn't weigh very much, and he taped the ends together so they wouldn't all come apart while we were driving. About half way up to the lake, we ran into an absolutely ferocious thunder and lightning storm. i was scared right to death that I was going to become a human lightning rod, hanging onto all that copper pipe, but Ernie said "Don't worry Brian, we are up on 4 rubber tires, the lightning won't bother us!!!" I don't know if he was right or not, but I didn't get struck by lightning. I was awful damn glad to get to the end of that trip, anyways.

Online Roger B

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Re: Bicycle Dynamo powered by model I.C. engine
« Reply #33 on: December 01, 2014, 07:23:23 AM »
Very nicely done  :praise2:  :praise2: and some more useful information and numbers to store for future use  :ThumbsUp:  :ThumbsUp:
Best regards

Roger

Offline Ian S C

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Re: Bicycle Dynamo powered by model I.C. engine
« Reply #34 on: December 01, 2014, 12:11:45 PM »
You might be better using a small DC motor for a generator, I use the ones in old HP ink jet printers(as I upgrade my computer, the old printer becomes obsolete), the motors rang from about 1 1/2" to 2" long, and 1" to 1 1/2" diameter, 12volt, and not very high revs, and they give quite good power at lower revs.
                                                          Ian S C

Offline Bruno Mueller

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Re: Bicycle Dynamo powered by model I.C. engine
« Reply #35 on: March 26, 2023, 12:44:33 PM »
The above contributions
are already almost 10 years old.
Nevertheless, I would like to show you my version of a dynamo made from bicycle parts.
I have disassembled the inner workings of such a dynamo. I knocked the existing axle out of the permanent magnet and glued in a new axle with Araldite.
There are two different arrangements of the coil.
In older dynamo models, the coil sits directly around the magnet core. These devices are wider in diameter. In another version, the coil sits behind the magnet core and the pole tongues grip around the magnet core. These dynamos are narrower in diameter, but the overall length is somewhat greater.
I have built and tested both versions.
For clarification, I have also made a dynamo with a transparent polycarbonate body.
Have a look at the different pictures.

In the first and third pictures, the coil sits around the magnetic core. All other dynamos are constructed like the transparent dynamo. The current connections are insulated in the housing.

« Last Edit: March 26, 2023, 12:54:50 PM by Bruno Mueller »
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