WOW!!!

I don't have any answers to your questions, but instead plenty of my own!

It looks like Ralph put in lots of time and $$ into his water wheel, and it looks VERY SWEET!

Did he design it himself?
How many hours ?
More PICTURES??!!  Please!
In operation,  are the paddles completely submerged?
Any idea how much the river level changes?   (low to high)
The picture you have posted,  does it show "average" flow?
Any chance of a video posted to .. say..  Youtube? (close ups would be nice)
Your posted tests..   What is the voltage at the tested current values? and what type of load?  
(in other words..   what is the output in WATTS?  with the two gear boxes?
During your tests..  what is the Unloaded voltage vrs  Loaded?
Can you stall the wheel by loading down the alternator ?

I'm sure I'll have plenty of other questions!.
Like whether you have any concerns of "cogging"  or regulation ect ..ect.
But I'll delay them for a bit..  

It's been years..   since I've posted my list of questions/ideas.. about building a water wheel.
I had a Lot of response from others that you may find interesting.  
If you are bored and have the time check out my dairy entries,
New Camera
Low speed hydo
How slow can it go?
and  Watts that?  Hertz much?
I got a few very good comments  Zubbly, Otzles , Nando and others!

Concerning Ralph's wheel and your alternator my "gut" feeling is that a "much larger" diameter alternator would help.  

I'd suspect that some others will be asking..  What type of load is Ralph looking to use?   as well as lots of others!  

The standard issues in a wind gen are very different from a hydo set-up!

Bottom line is...  WOW!
I'm looking forward to watching this project/thread!!

I think you are near the maximum output if your speed is being nearly halved when load is applied. Small improvements may gain you a bit but I don't think you are going to double the power out. Undershot wheels have to be really large to get much out.

You may be able to restrict the channel a bit and increase the velocity under the wheel.

It would be interesting to know your overall efficiency with gearbox and alternator. I doubt that there is a lot of room for improvement without a serious increase in cost but it may be that a lower ratio gearbox and a much larger and more costly slower alternator may have got you a bit more but there comes a time when the cost is prohibitive for the slight gain. You have probably got a good compromise.

Interesting project. Your power is maxed as it. Yet there is more to do.

The water flowing around the assembly must be aerodynamic in shape.
I see a flat area to the water. Causing turbulence to the water flowing into the blade area, restricting your power.
Shape the assembly to FUNNEL the water into the blade area.
2x water speed up can be achieved in the blade area.

Please include a picture of the wave, like to see how the whole blade area interacts with the water under load.

If the wheel sheared a 3-inch branch closing the spoke openings with something (hardware cloth, roll fencing, cedar lath slats, plastic fence lattice, etc.) would guard against that liability a long ways in the eyes of the Courts... Ya, I know but someones dog might think its better than rolling in....

I'd be voting for a self-tensioning serpentine belt if that was a category...

Also - working against natural creek bottom versus having a sluice floor to keep water piling up against the tines, that buncher claw could sure sneak some creek changes in fast...

If the bucket edges are submerged one foot deep, the flowing water it collects will slide up the curve (imparting energy) and then as it stops and slides back down, it imparts a little more. This will also cause less turbulence. By that I mean if the bucket edges were turning at 80% of creek flow speed, it might turn at 85% with less turbulence.

Hello Mitcamp

I've been trying to figure out an "elegant" way of asking the dollar investment in the water wheel,   the best I've come up with is   "What is the cost ratio between the water wheel and the alternator"    But that makes things difficult,  So.....  how much bling?

The Wheel appears to dwarf the alternator in both size and investment.
It surprises me that the "unloaded" RPM of the two different gear boxes are the same?
The 30:1 and the 45:1 have the same unloaded 8 RPM,    What is the wheels RPM without a gearbox attached?

With out a doubt, a great deal of time has been put into its planning and building.  During that, process was there ever a "calculated" power output?

A long time ago I had a chat (and I am not sure with who) about increasing wheel efficiency. It was suggested that if one were to put in vertical vanes in the water (leading into the paddles) that by reducing turbulence and causing the water to push against the paddles in a more "linear motion" more wheel speed would be achieved.  

It has already been posted whether spending the extra monies on larger alternator would be cost effective; however taking into consideration the investment already made it the water wheel.....  The way I see it   "In for a Penny, In for a Pound"

The current values you have listed,   is the total current, or per leg of three phases?

You mentioned 45 amps would be nice,    12v x 45a = 450 watts.
I would not be surprised if the 45:1 gearbox is not consuming close to that amount.  To say nothing of the year-to-year maintenance it will require.

I do not recall anyone here building an Ultra Low speed alternator, but that does not mean it cannot be done.   YES, it would cost a lot more than a standard "wind" alternator but this hydroelectric system is a very different animal.  
You may want to search low speed alternators.   I recall Vatman working on one,  but I've not seen recent postings from him.  

Looking forward to more pictures!

JMHO - YMMV

I'm thinking measure the flex on the bolts, then torque it with a 10 foot bar and some lead weight, the way you have it bolted makes other methods difficult.

The 45:1 gear ratio is good, it is able to load the wheel to about half the unloaded rpm.
But with only 180 RPM at the alternator, alternator efficiency is going to suck.

To get efficiencies approaching those of overshot wheels you make that happen deliberately, typically with the poncecelet design.  The blades are partially submerged and recede at half the speed of the incoming water.  The edge is tangential to the incoming water and so the water smoothly climbs the blade, pushing over more of its surface than it would if it were hitting a flat blade face on.  The water transfers most of its momentum to the blade as it runs up and back down, exiting with a backward velocity relative to the blade that makes it leave the mill with very little forward momentum remaining.

A poncelet can in principle get essentially 100% of the power in the water and in practical designs can get 70% or more, compared to typical pre-poncelet undershot designs that got maybe 35% if they were lucky and spent much of the rest creating heat and turbulence when the water hit the paddle blades face-on.  The poncelet's efficiency is thanks to that rise as the water interacts with the blade.

Check out this thread by Vawtman

I think this is the direction Ralphs alternator should head.

5. All the mags are on  (Mechanical, All Topics)
posted by vawtman on 08/24/2008 07:41:53 PM CST
29 comments (0 new)

(not sure how to post the direct link)