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Brady
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Posted: 20 August 2017 at 10:45am | IP Logged Quote Brady

Firstly, I would just like to say that I'm so happy and thankful for the responses I've gotten. I'm confident that my group and I will be able to complete this project. You guys are legendary. I will continue to post as the weeks progress, and I would really appreciate further tips.
oh! And before anyone asks! I'm not cheating! Our teachers greatly encourage looking for help on other sources and expertise, and I think I've hit the nail on the head.
Sorry I was late to reply.

I believe I will be able to access the river, either tomorrow or Tuesday. At that time, We will test the speed of the river. However, the problem is that the river fluctuates ALOT, and very adept to flooding. Sometimes, it can be calm, and relatively slow, while other times it turns into a complete monster! Especially after a rain storm. How could we measure the river speed with often fluctuations?

As for electrical power needs, we need to charge at least a battery with a MAh of 2000. But we can go as high as we can handle. In the end, we hope to be able to charge a battery, to charge a phone, from 0 to 100 percent. As for the phone I will be charging, it has a MAh of around 1500.

Ooh, and diode and weird bezel gear things. Like this?



The idea of using paddles and a floating platform seem like the easiest to make. Is this design possible?



I love the idea, keeping the generator out of water would been that I wouldn't even need to waterproof very much! I'll suggest it to my team tomorrow!

Thanks again,



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flc1
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Posted: 20 August 2017 at 11:18am | IP Logged Quote flc1

I think you should still have good waterproofing on your system,its close to the water and could still get water on it during storms when the river rises and starts to pump with small pressure waves etc.
If you find out what the flow is most of the time then that will be your average and you work with that flow rate, allowing for more of coarse when the river rises and the flow increases.
yep diode in the positive lead. And maybe look at a small charge controller to stop your battery from being cooked....not sure if they make them that small, or you could just go with small generator and charge controller and small 12 volt battery with small inverter to plug your phone charger into ha! unfortunatley it cost money , and would that be cheating?
That second pic you have there was what I was trying to explain...maybe make the slide ring loose and at the top of the float so its less likely to jam?, or use a swingarm? .
look forward to some pics of progress

Edited by flc1 on 20 August 2017 at 11:56am
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Warpspeed
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Posted: 20 August 2017 at 5:54pm | IP Logged Quote Warpspeed

Quote:
And before anyone asks! I'm not cheating! Our teachers greatly encourage looking for help on other sources and expertise, and I think I've hit the nail on the head.


Successful engineering is not about knowing everything, but about knowing how and where to find (or look up) the answers to problems. Books have been the traditional source, but the internet has now largely replaced libraries as a bulk store of accessible knowledge.

Definitely not cheating, but very wisely using the resources that are available.

Anyhow...

Wild unpredictable fluctuations in water height and speed, lend themselves to the floating paddle wheel solution. The simplest way might be a floating drum with paddles arranged around the outside.

If that was mounted on the end of a long forked boom, it could rise and fall with the water height and possibly even survive a fair flood.

The drum will need to be perfectly watertight or its obviously going to slowly sink.

Easiest way might be to just use a steel or plastic drum and bolt or screw your axle shaft and paddles to the drum and not worry too much about keeping the outer structural part of the drum water tight.
Then stuff the drum with small watertight objects to give it buoyancy. Maybe small plastic drink bottles? Whatever you can find that is both light and absolutely watertight, and you can pack a lot of them in there very closely.



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Boppa
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Posted: 21 August 2017 at 8:10am | IP Logged Quote Boppa

The paddlewheel is definitely a good solution and if you use a bicycle rim (a pair actually- one for each end of the paddlewheel) you could further distance your genny from the water, plus gear up to the speed required for the genny from the very likely lethargic paddlewheel speed by using the rim itself as part of the gearing- a rubber belt around the rim, and at the top it goes over the genny pulley, and you could attach the planks/blades to the spokes

re the first diagram



The motor would be at the top actually at the deck level of the bridge so easy to access, the axle and pole/axle tube would extend right down to the water and below
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Brady
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Posted: 21 August 2017 at 10:04am | IP Logged Quote Brady

I found this thing,



I was thinking of something like that, but larger, and use those Water dispenser containers you find in offices.
I would place the motor in the middle of the two containers. I'm sorta confused by that belt system... But I found this video showing me how gears work and stuff, http://www.askaprepper.com/homemade-water-wheel-electric-generator/
Its the second video down. Do you think I could do something similar as that old man?
Connected through the motor would be the axle shaft, on either end, over the containers, would be the paddles (I really like the idea of using drums or bicycle rims as the paddle wheel, I'llsee what I've got access to.)

I'm going to talk with my team tomorrow about the floating paddle wheel idea, it sounds simpler to make.
My question is that would it be Still necessary to test the speed of the river? If it's going to fluctuate a lot and the system will go with the tide, is there still a point to recording the river speed?
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Warpspeed
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Posted: 21 August 2017 at 10:17am | IP Logged Quote Warpspeed

What he said ^^^^

And a suitable slim and very flexible multi groove rubber drive belt and pulley that should not slip, (even when wet) might be found in a discarded tumble dryer.

The drum in a tumble dryer is typically about 20 to 22 inches diameter, and the matching multi groove motor pulley maybe an inch diameter.

I believe BMX bikes typically run 20 inch diameter rims.

Edited by Warpspeed on 21 August 2017 at 10:20am


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flc1
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Posted: 21 August 2017 at 10:47am | IP Logged Quote flc1

If you did know the speed of the water it may save time with testing.
As you bright young sparks should be able to work out from the speed of the water... the gearing ratio needed to get correct voltage.

Edited by flc1 on 21 August 2017 at 10:54am
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Boppa
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Posted: 21 August 2017 at 11:42am | IP Logged Quote Boppa

I was thinking more along the lines of a sternwheeler lol
but the twin paddles would work too






paddles could be attached to bicycle spokes via nuts/bolts with large washers, or even with cableties....

One thing you could do is measure the water speed, and if you put an ammeter in the lead to the battery (many schools still have them in the science labs I believe) if not a cheap multimeter with a 10A setting would work as well
Then you could chart various water flow rates with the current you get out of it

ETA
I just noticed- you have your diode backwards in the diagrams above- the silver/white banded end should be closest to the battery +, the unbanded black end would be connected to the motor +





Edited by Boppa on 21 August 2017 at 11:54am
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Warpspeed
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Posted: 21 August 2017 at 9:58pm | IP Logged Quote Warpspeed

This is really starting to look like something.

It may be difficult to find a way to use the original bike wheel bearings with a paddle wheel arrangement, but two bike wheels and wide paddles are probably still the best way to go.
You may need to remove the guts from the original wheel bearings, and slide the wheel hubs onto a suitable length of metal pipe.
Both bike wheels will need to be very solidly attached to this axle tube, or your paddles will just collapse.


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Boppa
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Posted: 22 August 2017 at 4:35am | IP Logged Quote Boppa

Not sure it would be that hard to retain the bearings if required- get a length of tube of the right length to run between the two rims- hammer one of the nuts that held the rim on the frame into the tube (That means testing tube sizes until you find one that is just the right size- then on the other side use right angle steel to form the upright from the float- drill hole and tighten other nut from bike frame to hold axle in place

Come to think of it- if the floats are held fore and aft with rigid bar/angle- I dont really see the need for the center axle at all (between the two rims)- just the one side held would probably be enough

Another option for a center axle is the threaded rod found at hardware stores with the same thread as the bike axles- They also have 'joiners' that allow you to join two threaded rods together (like a really long nut) joiner connects bike axle to threaded rod- then keep joining until you get to your required length- then another joiner to the other rims axle

example of joiner at bunnings joiner
Threaded rods of various sizes/threads threaded rods obviously you would select rod and joiners of the same size/thread as your bike rim axles
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Brady
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Posted: 22 August 2017 at 4:39am | IP Logged Quote Brady

So, I've have been with my group today, and they are really supportive of the floating paddle wheel.

We have begun construction of a very small paddlewheel model. It's not going to be much, it's only made to see how fast the water is, and puts it into perspective of what we have to build. We have cut out 8 wooden paddle things, around 11 cm long, 8 cm wide. The paddles will be attached to a wooden axis, the paddle would floats amongst two small plastic water bottles. We will throw it into the water and see what works.

After that, we'll go onto our main model. Which will be able to produce electricity.
Very excited for the testing phase.
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Warpspeed
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Posted: 22 August 2017 at 6:58am | IP Logged Quote Warpspeed

To measure the speed of the water, all you need to do is toss a floating object into the water and time it with a stop watch over a known distance.
Between a convenient rock or a tree and your bridge for example.

From that we can work out from the diameter of the paddle wheel how many turns per minute a given diameter paddle wheel is going to turn.

When you eventually get an electrical generator to test, you can turn that by hand to see how fast it needs to spin to do the job. A lot of things can be measured and worked out and anticipated, before actually testing the final completed turbine in the water.

Building a small scale model first is a very good idea. It can tell you what many of the unexpected difficulties might be, before you start work on the final full sized turbine.

Once you have made something, its always very easy to look back and think how you could have done it better, or made it simpler.

If its only a small model, you can trash it and start again and use your improved ideas in the next improved version.

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