Author Topic: 5kw Poncelet Wheel Project  (Read 149381 times)

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skid

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Re: 5kw Poncelet Wheel Project
« Reply #264 on: December 15, 2017, 01:08:27 PM »
Hi Rob,

Replacing the bearings improved the oscillation situation quite a bit. I am still getting swings, but the magnitude is much less. I don't know what normal should be however. I would think the water speed would be constant so the output should be constant.

Mary B

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Re: 5kw Poncelet Wheel Project
« Reply #265 on: December 15, 2017, 05:17:57 PM »
I would think your water wheel is going to see small pulses each time a blade is first in contact with the water and as one exits. Theoretically they should cancel but slight tolerances could make the torque uneven. Measure the rpm of the wheel, if it shows a regular speed spike that is the issue I bet. It may only be slight but enough to show in the inverter output.

ontfarmer

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Re: 5kw Poncelet Wheel Project
« Reply #266 on: December 15, 2017, 06:22:10 PM »
I have been following this is there a way you can add weight a ( Flywheel ) to the wheel or the alternator?  May be better on the alternator because of more RPM.  I think that may help even the drive.

hiker

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Re: 5kw Poncelet Wheel Project
« Reply #267 on: December 15, 2017, 07:50:07 PM »
should make for a more even speed..not more...just my observations on my exersize bike gen..with mags mounted to the flywheel..
WILD in ALASKA

skid

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Re: 5kw Poncelet Wheel Project
« Reply #268 on: December 16, 2017, 10:29:12 PM »
I have been following this is there a way you can add weight a ( Flywheel ) to the wheel or the alternator?  May be better on the alternator because of more RPM.  I think that may help even the drive.

The belt pulley on the wheel weighs around 600 pounds. I thought this would smooth out any oscillations.

ontfarmer

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Re: 5kw Poncelet Wheel Project
« Reply #269 on: December 17, 2017, 05:06:02 AM »
 What is the ratio of the drive?  I was thinking of one on the alternator that has quite a bit of diameter.  Just a thought.

dbcollen

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Re: 5kw Poncelet Wheel Project
« Reply #270 on: December 17, 2017, 10:03:28 AM »

Replacing the bearings improved the oscillation situation quite a bit. I am still getting swings, but the magnitude is much less. I don't know what normal should be however. I would think the water speed would be constant so the output should be constant.

The oscillations are likely caused by natural turbulence in the river.

SparWeb

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Re: 5kw Poncelet Wheel Project
« Reply #271 on: December 17, 2017, 01:52:06 PM »
Skid,
Have you checked yet to see if the oscillations change with the depth of the wheel?
I have a feeling that when it's 1/2 submerged (water at the axle) the oscillations would go away.
If the oscillations go away when it's that deep, then you can be sure it's torque from blade entry/exit when it's less submerged.
If they are still there, then it's probably something else.
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
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MattM

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Re: 5kw Poncelet Wheel Project
« Reply #272 on: December 17, 2017, 09:29:57 PM »
dbcollen is probably on to something with natural turbulence.  Water flow oscillates naturally in a river, shifting from literally an infinite number of variables.  At least the pulsing flow should be fairly uniform by the hour.  Surely it's not a huge delta from crest to trough with each pulse? 

One thing that is surprising is that visible wave action on top of the water has almost no effect on what kind of force is provided by the waterflow.  I've actually rode wave crests moving upriver and could feel the resistance shifting rhythmically as I was trying to beat a storm coming in from the south.  Likewise, I've seen crosswind on a river that actually created strange riptides downriver.

Bruce S

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Re: 5kw Poncelet Wheel Project
« Reply #273 on: December 18, 2017, 03:22:09 PM »
Hey All;
Might be a lot late to the party, but is it possible ti's also out of balance? I re-read through the posts and didn't see any mention of a static balance, though the beauty of the this project it's was done and I didn't see the mention.

isn't water also 8x dense as air, and the resulting oscillations magnified as such too?
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Bruce S
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paara

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Re: 5kw Poncelet Wheel Project
« Reply #274 on: December 19, 2017, 01:01:55 AM »
Air is pretty dens where you live ;) you meant 800x ofcourse. Wouldn't the mass of water and metall resist surges. Is it not more likely that it is due to a mppt function in the invertere?Letting the rpm increas over time (minutes) due to small fluctuation in flow, then increasing the resistance/power removed from the system which resultater in a spike of power and slowing og the rotating mass/water wheel. And then repeting itself once in a while. Rpm increase until the mppt reach a certain voltage treshold? If the mppt does not have infinite voltage ofcourse just a thought.

Some new pictures would be great by the way ;) impressive setup you have. Beats solar power hands down.

skid

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Re: 5kw Poncelet Wheel Project
« Reply #275 on: December 19, 2017, 02:09:31 AM »
Might be a lot late to the party, but is it possible ti's also out of balance? I re-read through the posts and didn't see any mention of a static balance, though the beauty of the this project it's was done and I didn't see the mention.

I never did balance it, as I thought it would turn too slow to matter. I did spin it a few times and it would come to rest in different places so it can't be too bad.

Severe out of balance would show as 1x issue, meaning you would see the problem every revolution.

Paara and Rob Beckers have it right I think as it is probably a MPPT issue. I was seeing 200W swings today. Rob's given me some advice on how to download the program, but I haven't done that yet as I'm busy with another project right now.

It's supposed to drop below freezing later this week so I'll try to look at the inverter programming when I pull the wheel out of the water.

keithturtle

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Re: 5kw Poncelet Wheel Project
« Reply #276 on: December 19, 2017, 02:10:58 PM »
I don't know what normal should be however.

You will in time; keep at it.  I love the progress, and the fact that it makes power when the sun doesn't shine

Turtle
soli deo gloria

george65

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Re: 5kw Poncelet Wheel Project
« Reply #277 on: December 19, 2017, 07:17:24 PM »

It's supposed to drop below freezing later this week

It's supposed to go over 40C ( 100F)  AGAIN here today.
How 'bout we help each other out, I'll send you all the temperature you want to keep your river thawed and you send me all the Cold/ snow/ ice you want to offload so I don't cook like an egg every time I go outside.

Reckon if we can work out how to pull this off we are going to be very rich men and you'll be having that water wheel  gold plated!   ;D

MAL

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Re: 5kw Poncelet Wheel Project
« Reply #278 on: December 31, 2017, 02:32:43 PM »
I thought extending the inner lip of the bucket inward with a curl, more like the Poncelet design, to capture more of the energy.  Once the flow  "hits the wall" the  velocity will play a bigger role

Longer blades extending out further will do the same thing I'm hoping. If after adding longer blades and water still pours out the middle of the wheel I will seal the blades off as there is definitely lost energy there.

I was carefully analyzing the wheel's operation yesterday and noticed that the blade slap is actually the water hitting the front of the blade, not the rear. Sounds like the bass drum in a teenagers car stereo. My neighbor says he can hear it when he is near the river.

I think you are on the right track.  Blade design is the issue in my opinion.  A good blade design should enter and exit the water cleanly without disturbing the water any more than necessary.  If your blade is causing a splash of water on entry or plowing water on exit there is room for improvement.  If sound control was the only issue It should be easy to reduce the noise by adding some sort of rubber boot or support...kinda like putting your hand on a drum to deaden the sound, but I believe the sound issue is related to efficiency.  Raising and lowering the wheel also changes blade entry and exit, part of the answer could be in wheel depth.
You may get more speed from having the wheel higher, but you may get more torque by having the wheel lower.

skid

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Re: 5kw Poncelet Wheel Project
« Reply #279 on: January 18, 2018, 07:47:19 PM »
I've been running a couple months or so on the new roller bearings and think they may now be water damaged as well. I haven't checked yet to see for sure but will do so tomorrow.

I did make a call to a company that makes lignum vitae wood bearings and am getting a quote to see what the cost might be to go that route. The very helpful chap I spoke with thinks I could get a life time out of the bearings as long as I can get enough water to lubricate them. Kind of opposite the problem I'm having now.

SparWeb

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Re: 5kw Poncelet Wheel Project
« Reply #280 on: January 19, 2018, 07:20:33 PM »
Cool.  Some new problems are really old problems - and there's an old solution for it.
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
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keithturtle

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Re: 5kw Poncelet Wheel Project
« Reply #281 on: January 20, 2018, 12:53:17 AM »
I bought some of this for the underwater part of my reaction turbine

https://www.vesconite.com/vesconite-hilube/

but the dam washed out before I could try it.

Not sure if the weight of your wheel is more than it could handle, but they say it's pretty tough

Turtle
soli deo gloria

skid

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Re: 5kw Poncelet Wheel Project
« Reply #282 on: January 20, 2018, 06:14:18 PM »
I bought some of this for the underwater part of my reaction turbine

https://www.vesconite.com/vesconite-hilube/

but the dam washed out before I could try it.

Not sure if the weight of your wheel is more than it could handle, but they say it's pretty tough

Turtle

That's some cool looking stuff! I had also considered similar Teflon and other plastic materials as well (UMHW, etc.).

The lignum vitae company would machine the bearing replacement out of one piece of wood to replicate the existing pillow block size, and then bore a 70mm hole for the axle to go through. Simple. Just slide it on the shaft and bolt it down. Waiting for costs, but it cant be too much more than a 3 inch tapered roller bearing. Apparently it is an endangered species, but this would be a good use for it.

I checked out the roller bearings today and there doesn't seem to be a problem. I didn't disassemble anything, but they spun nice with no noise so I gave them a shot of grease and put the wheel back in the water. I may still buy the new bearings to have on hand if I need them.

skid

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Re: 5kw Poncelet Wheel Project
« Reply #283 on: January 20, 2018, 07:21:06 PM »
I made a short video of me greasing the bearings and rotating the wheel back into the river.

https://www.youtube.com/watch?v=PvmUrDfp3sE

My riverside control panel is a bit of a mess as I had to tee in hydraulics from my tractor. The battery for the hydraulic motor went dead since there is no sun for the solar panel to recharge it, and I've been raising and lowering the wheel quite a bit to determine the best height for generation. I also still need to cut into the main power cable so I can get an output readout at the river.

I still need to pour a concrete base for the panel as well so I can get rid of the 2x4 supports so it doesn't tip over in a windy situation


SparWeb

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Re: 5kw Poncelet Wheel Project
« Reply #284 on: January 20, 2018, 09:07:30 PM »
Looking good.  It's so well balanced you can pivot the whole rig with a gentle push!
... dogs are welcome too :)
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

Mary B

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Re: 5kw Poncelet Wheel Project
« Reply #285 on: January 21, 2018, 06:09:21 PM »
That thing is awesome! One of the top ten builds on here!

Are you planning a river level sensor and a way to automatically have the wheel track river depth?

skid

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Re: 5kw Poncelet Wheel Project
« Reply #286 on: January 22, 2018, 12:58:41 AM »
Are you planning a river level sensor and a way to automatically have the wheel track river depth?

At some point in the future I will do that, but currently need to resolve some bigger issues. Water flows don't change that much unless we get heavy rain, and even then the wheel is quite tolerant of water level changes. Once spring comes and the snow starts to melt I don't think I'll have to adjust things too often. I follow the gov't river gauge on my computer so I can see changes in real time without having to be physically at the wheel.


MattM

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Re: 5kw Poncelet Wheel Project
« Reply #287 on: January 23, 2018, 09:52:40 PM »


The simplest design was used 100 years ago.  Straight blades with slight tilt allow the wheel to rotate with minimal leading edge drag.

skid

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Re: 5kw Poncelet Wheel Project
« Reply #288 on: January 24, 2018, 12:57:36 AM »


The simplest design was used 100 years ago.  Straight blades with slight tilt allow the wheel to rotate with minimal leading edge drag.

Simple yes, most efficient no, according to Poncelet and other engineers. My view is that in this application,  the more blade area the better. Curved blades have more area. If manufacturing would have been easier, I would have made decreasing radius curved blades to better utilize the water that is being washed over the tops of the blades. I'm looking at the possibility of lengthening the blades another foot, as well as going 20% wider on the lengthened portion to maximize efficiency.

Despite the wheel rotating nicely on the shore, and getting a really good grease, there is again noise coming from the bearings. I'm finalizing my order of the lignum vitae bearings. Hopefully should get them in a couple of weeks. Keeping the wooden bearings wet shouldn't be an issue as there is water constantly dripping from the wheel into the bearing area. If I have to, I'll drill a hole in the wood and put a funnel in it to capture the water and force it into the bearing...

MAL

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Re: 5kw Poncelet Wheel Project
« Reply #289 on: February 02, 2018, 02:58:33 PM »


The simplest design was used 100 years ago.  Straight blades with slight tilt allow the wheel to rotate with minimal leading edge drag.

Curved blades will are definitely a better choice.  They will capture more water and exit the water without unnecessary drag on the trailing edge.  Your image of the water wheel does show the proper angle of blade entry in my opinion...the blade exit is good, but would be better if the blades were curved.

MattM

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Re: 5kw Poncelet Wheel Project
« Reply #290 on: February 02, 2018, 09:59:18 PM »
I don't think you want to catch water, just create drag optimized with respect to direction of flow.  It's more or less working on a similar principle to a VAWT.

MAL

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Re: 5kw Poncelet Wheel Project
« Reply #291 on: February 02, 2018, 11:34:20 PM »
I'm not sure that we are disagreeing. I said "capture more water"  Skid said "more surface area"...I was agreeing with him, but I chose different words.  If you think Straight blades are better then we still disagree.

MattM

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Re: 5kw Poncelet Wheel Project
« Reply #292 on: February 03, 2018, 02:46:21 PM »
I'm all for curved, but I'm the guy that likes s-curves aka ogees.

hiker

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Re: 5kw Poncelet Wheel Project
« Reply #293 on: February 03, 2018, 05:57:49 PM »
build a few models..run under your sink faucet !!
WILD in ALASKA

MAL

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Re: 5kw Poncelet Wheel Project
« Reply #294 on: February 04, 2018, 08:38:32 PM »
I'm all for curved, but I'm the guy that likes s-curves aka ogees.

I tried to search ogee blades on a water wheel...I couldn't find anything.  Do you have a link or an image that you could share?

MattM

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Re: 5kw Poncelet Wheel Project
« Reply #295 on: February 05, 2018, 07:57:48 AM »
I don't believe there is anything that's ever been tried and measured.  I'm pretty convinced that squeezing more area out of the blade requires something not straight.  An ogee does that.  The trick is to keep a positive slope across the entire curve and not to overdo the curve into a negative slope.  I only played around with ogee shapes on axial turbine lawn ornaments using sheet metal.   I figure mother nature developed s-curve/ogee shapes for a reason.   And mother nature shapes tend to be flexible, where's manmade stuff tends to be rigid.

Apologies for the thread derailment. I love skid's updates!

skid

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Re: 5kw Poncelet Wheel Project
« Reply #296 on: February 06, 2018, 12:58:03 AM »
Poncelet's curved blade design incorporated a constantly decreasing radius curve. It was less curved at the outer diameter, and more curved at the inner diameter, like the outside of a French curve template.
Ideally this is the way I would have built the blades. However, the shop that curved the aluminum blades wasn't capable of that, at least not without spending a pile of money.

The wheel is still running on the roller bearings. Maybe there is nothing wrong with them? I've ordered the wood bearings and they crossed the border from the US. Hopefully I'll get them sometime soon. I sometimes lay awake at night thinking the roller bearings will fail and the wheel will fall into the river and get washed away forever :( :o :'(  Do people's solar panels keep them up at night worrying?