Another Water wheel project

[Cliff top]

From a seed idea planted by Dick Strawbridge, I've spent 3 yrs waiting to be able to do my own 'green stuff'. Moving to our 3/4 acre plot on the western flanks of the Pennine moors we have 2 streams running through our land. One a local beauty spot, has a high water volume coming across a ford and dropping 3feet on to our land- I doubt I could harness this but one can but dream

The other, is much more usable and I have spent since last summer repairing,re-enforcing and heightening the dam wall to make a 1.1metre drop and space for a 1metre wheel. The stream might dry up in summer ,but not last summer



There was a small 'lake' behind the original wall, but it is a bit bigger now!

The stream runs at least 20 litres/sec at its lowest to an inestimable amount after it rains hard

[Cliff top]

OK, so having watched Pogster and Jensens projects come along, I have been trying to learn the valuable lessons in the hope of maximizing the efficiency of my project, and of course lowering my electric bills in to the bargain
I recently acquired a large cable drum for the wheel. It seems quite well made, and hopefully might last 3-4 yrs until perhaps a Mkii version comes along. I am making an overshot wheel, for the best efficiency and since we get debris from time to time, less chance of it snarling up in the mechanism etc.
Its hub diameter was too close to the centre so I have built up another layer which forms the back of the buckets. Most of the wood is from pallets/packaging timber (spruce/larch?) so shouldn't rot too easily.

This gives buckets with about 20litre capacity as far to the outside as I can get them.


I am currently making/shaping the tops to the buckets, a bit of trial and error.
Plus I am currently looking for the bearings and shaft etc, and a decent sized primary gear like Jensens

[guydewdney]

for an overshot wheel - you need to look closely at an american company called IXL - the bucket shape is critical to efficiency. The bucket shape you are currently working on is about 300 years out of date  sorry.

You need more of a J shape - with the upright of the J being tangential to the wheel, inline with the water in (ish).


cable drum is a good idea - should be sturdy!


It looks like you have more drop further on in the streams path, rather than whats at the dam - can we have a pic of downstream from the dam?


for bearing s etc try fish4parts - cheap and quick

[Cliff top]

Yes. I've seen the J shaped bucket design and fancy making some folded metal buckets at some point if that will get more power. I was thinking about putting some shaped pieces in the bottoms of each bucket to steer the water rather like the J.

As for downstream, I do have another 3-4 foot drop over about 70 foot on our land. I looked at this but I would have to find a way to sluice the water 70 feet to get a 7 foot wheel. The wheel would also then be visible down near the lane, attracting the attentions of ?



I also looked at the possibilities of the fixed 1.8m turbine, which may be a more efficient idea, but it would need a long large dia pipe and in summer may not have enough sustained flow to run.
You may see the blue 6" pipe I put through whilst restoring the wall to divert the water. The top end of it blocks up easily. I did also consider a turgo spoons turbine on that but  theres only 4' head and I would lose a lot of the flow volume. A while back, supply of bits seemed a problem, but I see Renewablecomponents.com now have some units available here.

[Ivan]

Turgos aren't designed for heads as low as this, but they will work, albeit not the most efficieny option.  If you do want to go down that route, you'd be better off looking at a Navitron turgo. You could modify it with additional jets to make it produce usable power at lower head.

The Navitron low head turbines might be a good option. What head can you muster? Water wheels work very well, so I wouldn't give up with that. The only problems are 1)gearing to get a usable rpm 2)ensuring that there is an overflow to allow water to escape during periods of flooding


The Navitron low head water turbine is designed for a channel rather than a pipe. There are some pictures of an installed system here on the forum if you do a search


Ivan

[Cliff top]

Thanks Ivan.

You mentioned before that you may have some other PMAs.
What PMAs have you that will fit what I'm doing here?  (assuming 24volt battery pack, PSW inverter)

I like the look of these:  220rpm..less step up required.
http://cgi.ebay.co.uk/Permanent-Magnet-Generator-1100W-Wind-Turbine-Hydro-Bio_W0QQitemZ250232868372QQihZ015QQcategoryZ41981QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

cheers
Andrew

service  at  wilkinsons dot tv

[Ivan]

Quite a number of people have used the standard wind turbine alternators to couple up to waterwheels. They are very rugged, much heavier built than most of the PMAs on the market. However, I'd still strongly consider the water turbine option. Building your own water turbine is a hard job - much harder than building a water wheel. Your main problem is keeping the water out of bearings - if it gets in, it washes the grease out and it fails fairly soon after. Home made turbines tend to be unreliable. A home made water wheel is an easier project!

I guess the 220rpm speed quoted in the ad is the speed at which it starts charging. It seems to suggest 500W is the rated speed, although obviously if you don't want or have that much power available, then lower rpm is an advantage

Ivan

[Cliff top]

I've now trialled the wheel in its final location and although not finished it does give the impression of how its all going to work.

I fitted some plastic troffin pieces, opened out by heating/melting, into the bottoms of each bucket. I am yet to put on some metal plates to make the buckets deeper/stop the water leaving as soon.


I didn't want to fit them until the wheel was in situ in case I bent them.

Using a fence post greased up as an axle and a quick built sluice we were able to see how well the bucket design works. Free running the wheel runs at 40rpm and the water is rather flung off due to centrifugal force, but when we slow it with a wooden brake, each bucket fills really well and the force required to slow it with 4 buckets (at 11 litres) full is immense.



Off to sort out a gearbox I've just found, a vari speed 3:1  to 22:1 Kopp gearbox and a shaft for the wheel.

[Cliff top]

Have just put up a video of it in action

www.pfmrs.plus.com/andrew/waterwheel/wheel.mp4

[northern installer]

Hmmn,jobs coming along nicely cliff;what sort of rpm are you expecting to drive the alternator at?

[David]

It is indeed coming on nicely. I will be interested in seeing its development. Please post some pictures as it is completed.

However, I would supplement it with a turbine in order to get the most electricity out of the stream.

[northern installer]

David,did you actually agree with one of my posts just then?

[Cliff top]

The wheel is free running at 40rpm.  So ~I expect 20rpm on load, the buckets work better then too.  The Kopp gearbox (Allspeeds Kopp) I've found has an 8:1 fixed box followed by a 1:3 to 3:1 variable, so in theory I can get 24:1 step up (22:1measured in practice) This would mean running the Kopp at its limits which won't be good for life etc so if I had it at say 16:1 followed by say 3:1 sprockets to the PMA thats 960rpm. This would seem to fit well within the  250-1000rpm usable efficient slope of the PMA. The beauty is the Kopp allows infinite adjustment to balance it for the power available. It has a 3/4" input shaft and a 1/2" output so looks to be up to the job. It all depends on the actual torque/power the wheel will give, which having just seen it run is very promising.
I need some more info on PMA outputs etc to make a decision on which to buy now.  The Wind blue running hot and only good for 500watts may be too small for this wheel when the stream is up more
I'm also looking for a 1.5" (mild steel probably)  shaft as I've got a pair of nice 'old' plummer bearing blocks in 1.5". Anyone any ideas where to find used?

Ivan, do you have any specs on the PMA you can offer? in particular current output vs rpm?

[northern installer]

Cliff,960 rpm is a standard motor speed,so might be good for the 'using an induction motor as a generator' scheme suggested by others on here;caution with running a Kopp anywhere near its limits,they do seem to give trouble if abused;might be an idea to use the kopp for experimental load work,then revert to fixed gearing (or chains or belts) when the optimum ratio is found?

[pogster]

Cliff,960 rpm is a standard motor speed,so might be good for the 'using an induction motor as a generator' scheme suggested by others on here;caution with running a Kopp anywhere near its limits,they do seem to give trouble if abused;might be an idea to use the kopp for experimental load work,then revert to fixed gearing (or chains or belts) when the optimum ratio is found?

The induction motor as generator is fine provided you have a minimum constant flow, As your sream flow varies greatly like mine then this probably would not be suitable.

Go for the PMA if I were you. Thr Windblue 520 makes 20A at 1000RPM into 24V batteries (not 10 like mine - the 540) or the previous sugggestion

http://cgi.ebay.co.uk/Permanent-Magnet-Generator-1100W-Wind-Turbine-Hydro-Bio_W0QQitemZ250232868372QQihZ015QQcategoryZ41981QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

which will produce 1000W Which is 40A into 24V batteries!