ST head in hydro installation?

[greasyhands]

Hello everyone!

I just found your group and have been going through all the threads eating up info on these lister engines! They are way too cool and I want one!
I'm also intrigued by the ST generators (even with the downsides listed) I really like how both units are *built* for simple servicing in the field.

I'm on an 18 acre farmette with a stream that used to be channeled to a mill. I'm seriously looking into micro-hydro, and was wondering about using these ST heads for that purpose.

Having only delt with auto alternators before, I'm starting to realize that you have to keep the generator at a constant speed to get the desired voltage/Hz. This would seem to be impossible with a water wheel or turbine.

My question: is there anyway to utilize a 120v 60Hz generator in my system to avoid a battery bank? If not, is there a large DC generator of the same simplicity and cost that would have hte same sort of advantages as the ST heads?

Thanks for any help and I'm looking forward to learning more about all these these wonderful machines!

Chris in Pennsylvania

[ronmar]

Well you could rectify the outut of the ST head to get DC and use this to feed an inverter for accurate AC output.  Since you are going to be building the mechanical interface from turbine wheel to generator head(and perhaps the turbine wheel itself), I don;t think it would be particularly difficult to incorporate a flyweight governor into the design, similar to that found on the listeroids.  The spinning flyweights find equlibrium with a spring.  Any changes in RPM cause a shift in this equlibrium and result in mechanical movement.  This movement would have to be directed to a wastegate on the turbine(similar to that used on turbochargers).  The force necessary to operate this wastegate would determine the size of the flyweight governor weights.  This could of course also be done electronically with a servo connectd to the wastegate.  The servo controller would position the arm based on voltage or RPM sensed.

[dkwflight]

Hi Many years ago I read In Popular Mechanics, I think, about a generater run by a water wheel.
The main problem was regulation, as I remember. I think the guy used a load bank to dump extra energy into the waste water. The regulation scheme was not well explained but they did not attempt to regulate the water flow except in a rough way.
Hope this helps.

[Doug]

Nothing is impossible if you have a ready source of power and time to tinker.

If i had about 15 feet of head and in the order of about 1 to 2 cubic fet of water flow per second I would probably look at an overshot water wheel. The mass would store a lot of energy for sudden load changes and 1 to 2 feet of water isn't a lot of flow to control so a govener system probably wouldn't be that hard to build. Combined with load dump like a hot water tank you might be able to get a couple of thousand watts from a system like this.

Much better turbines can be had to extract more energy from water, but I like slow moving and heavy mass because it gives even a crude  govener time to react to speed changes.

Doug

[adhall]

Greasyhands:

You might want to check out Home Power magazine. They have articles about micro hydro systems (among other things).

Here's the link:
     http://www.homepower.com/

Best regards,
Andy Hall

[Doug]

Wow thats almost creapy....

I wonder if I read this before?
I never bought this but it looks familiar...

http://www.homepower.com/files/overshothydro.pdf

But as I was saying this is is easy, just not very efficient.

[fattywagonman]

Good call Doug,
That article is from 93'...
I wonder if they're still at it?
Anyone in forumland know these folks?
They're not too far away from me... I'd like to drive out and meet them sometime...
 I noticed a couple things like having to rebrush every couple of years... and sometimes they go without water for 3 months in the summer...

Greasyhands,
A DC inverter set up would provide standby power... IMO a PM alternator with load dump into a water tank would be a good candidate  for a gen head...

If you want to make AC 24/7 an electronic regulator could control the supply or use a crude form of automatic load regulation to regulate RPM... I think Doug could help you with this...



If you go with AC I would suggest using this generator from harbor freight...

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=45416

It is frequency regulated and brushless and I'm a big fan of brushless design...

If you want a PM alternator capable of high output try one of these

http://shop.electricross.ihoststudio.com/productinfo.aspx?productid=MOTOR-ETEK-BRUSHLESS

[adhall]

Doug:

I wouldn't be too surprised if you and I read a lot of the same stuff...

Yeah, the belt driven speed-up arrangement is pretty Rube Goldberg looking. I would bet that if the builder had sat down and studied the Gates design manual, he would have never even tried it. I would be real surprised if the belt that's driven by the water wheel shaft doesn't tend to slip.

On the other hand, he seems happy with the results. And the efficiency doesn't matter much if he's generating enough electricity and he has all the water he needs for doing so.

Best regards,
Andy Hall

[fattywagonman]

If it's in a wet environment I'd suggest some of this stuff....

http://www.hydrogenappliances.com/marine.html

These guys also sell small PMA's

http://www.hydrogenappliances.com/powerpmas.html

just think of all the hydrogen that could be made with the excess electrical power...

[Doug]

Doing something like this has been in the back of my mind for quite some time....

I live in a very hilly and wet part of the country, its just a matter of finding the right property if I can ever convince the wife to abandon the burbs for something a little more rural.

My personal feellings are that a good over shot water wheel possitioned so the tail stock is pointed at the front and the wheel turns in the direction of the of the outflow is simpler and better than any turbine. Not because it efficient but because all that mass will dampen the effects of load changes.

I might consider a PM alternator for this or a standard brush type with some modifications. A simple govener could be rigged to control some of the flow.

I also like the Idea of of DC but you never know how something like this might end up. You may end up a long way from your home to the water source. In that case I might generate 600 v and build an MG set with a battery bank at the power house to make and store suplimental power.

Looks like location is the key and this fellow at the homepower site has it....

Doug 

[Doug]

If it's in a wet environment I'd suggest some of this stuff....

http://www.hydrogenappliances.com/marine.html

Seen it, used and impressed by it.....
I don't know about its electrical properties but we did use it in some gear boxes and parts.
Cost was an issue so it was used sparingly only on things like gantry cranes

[phaedrus]

I've overhauled large hydros - and can tell you that, while do-able, it's a serious engineering job to use an ST in a small hydro - you're going to have to design-build penstocks, wicket-gates, governor-control system to maintain rpm. You'll have to have a considerable storage capacity too, for water.

Much more pragmatic is DC alternator with permanent magnet rotor and inverter.

[Doug]

In a lot of respects an overshot water wheel is self limmiting with regards to speed and very slow in reaction to laod changes because of its mass. Building controls for it doesn't have to be all that complicated. A good load dump could probably absorb as much varriation as you could with flow control. Use both and I bet you couyld manage a very reasonable load regualtion for a home system.

This is all speculation and educated guesses on my part but I work with a lot of high inertia machines and see some parrallels...

Doug

[greasyhands]

thanks for all the feedback and ideas!

my situation calls for an undershot wheel as I have a lot of flow, but very little drop/head.
sounds like generating AC would be complicated and rely on things that IMO would affect reliability. I'd want this to be as reliable as possible, and servicable by me. (main reason I was looking at the ST heads!)

So at the risk of sounding dumb here, there isn't a good way to make AC with the varying speed that I would have.
DC on the other hand, would only make more Amperage as the speed increases, where the voltage would remain constant? Therefore, a better system for my hydro. (charging batteries and using an inverter for the AC)

any ideas for such a reliable, easy to service DC generator?

[adhall]

Greasyhands:

Here is another article from Home Power that describes a low head installation:

     http://www.homepower.com/files/homebrewhydro.pdf

In this case, they are using an axial flow turbine. Frequency control is done by using a variable dump load. Unfortunately, the article is short on details, but may provide some food for thought.

Best regards,
Andy Hall