PMA with a hydro turbine

[bob g]

all diodes are not created equal

there are avalanche diodes which are typical of automotive alternators

such clamp at~30volt for the 12 volt alternators

then you have to be concerned with recovery rates, those suitable for 50/60hz

can go into full time conduction when met with 400plus hz, again clamping the output

so you need a fast recovery, high amp (twice what you need in my opinion) high voltage non avalance (twice at least of your system voltage) and fast recovery.

this effectively precludes the use of those nice large and well priced rectifier bridges that commonly come up on ebay, that were used in industrial drives and other 3 phase rectification because they are not fast enough.

look for hd early bridge rectifiers from the alternator oem, early versions did not use avalanche diodes and were fast recovery.

bob g

[cattlefarmer]

The turbine is a 20" vertical wheel that's 8" wide.  There are 3 - 1 1/2" jets on there own ball valves.  The one valve stays open and I use one of the other ones to fine tune the speed.  I can run it a lot faster but then what to do with the extra power?

I'm sure I typed that I had 160' of head with a pipe run of 385'.  The cost dose not play out right to drag power 2 miles and connect it to the grid.

I currently have 2 units that just need new rectifiers, diodes, and bearings.  The low hour one that's on there can go back in the box for the back up.

[hydrosun]

After I wrote my reply I went back and looked that you had 160 feet drop. Now you say you are using 1 1/2 inch nozzles (1.5) inch. Is that right? A 1 1/2 inch nozzle at 160 feet will let out 560 gallons per minute. A 50% efficient hydro would put out over 8000 watts.  Either you set up is only 10% efficient or your numbers are wrong somewhere. You may have a gross mismatch of speed or the alternator just isn't capable of putting out more power at that speed.

Chris

[ghurd]

The alternator is horribly inefficient, if it is anything like I think it is.

That's why I think it would be worth a try Jerry Rigged, to increase the efficiency and reduce the heat.

If it is anything like I think it is, I am honestly Very surprised it can make that much power at any RPM.

Things I wondered about and have no idea:

Seems like the nozzles are too large for that kind of pressure and flow?

Seems like the size of the drop pipe is important for a 385' run feeding three 1.5" nozzles, and 8" seems a bit small?

I don't know.

G-

[cattlefarmer]

I'm running an air compressor and the PMA off the turbine.

I have put out larger amounts of power in the past but why make huge amounts of power to turn around and dump it?

I went tot town and got heavy duty bearings, rectifiers, diodes, and an amp meter.  I got it all wired up and running.  I didn't add the new leads to it so it's still in star.  The new amp gage says I'm putting out 34 amps, my clap on says it's 24 amps, and the clamp on I browed says 33 amps.  The meter caused me to be wrong on how many watts I was making before.

[TomW]

cattlefarmer;

Wouldn't be the first time a low set of batteries in a  meter tossed an inaccurate reading.

Fairly common for meter batteries to be the true culprit.

I try to not believe wildly unusual readings on any battery operated meter until I know the batteries are good.

This is a valuable lesson on not blindly trusting equipment when it shows something wildly different from what you would expect.

Well now you can be more accurate in your assessment of the values you are getting.

Good luck on the system.

Tom

[cattlefarmer]

The batteries were about a year old it was reading the same after I put in new batteries.  It now has a big X on the unit and is in the junk box.  I'll pick up a new one next time I'm in town.

The AC and DC voltage settings work fine but the problem is in the amp clamp.

[locomotion]

Has anyone seen the screw pumps used backwards as run-of-river turbines? There are a number of new installations on youtube that I find simply fascinating. Go there and check out these videos, if you search "hydrodynamic screw or Archimedes hydro etc you will find them. One is in Torrs Mill in the UK, another 2 in Italy, and numerous ones in Germany. The first time I came across these on youtube I stayed up all night reading about them. I am amazed with my interest in hydro, I'd never before came across these.

My question is...what could one do to build one of these. Would a grain auger (probably too small in diameter) or some other scavenged auger work? The formulas and calculations for engineering them are mind boggling, and I wouldn't have the slightest idea how to even begin fabricating one. If I had the auger and trough I know how to make everything else work. I'm not talking a backyard science project here, but rather a viable and fully functioning hydro turbine.

Please check these videos out...I'd post liks, but I don't know if that is permitted.

IDEAS....THOUGHTS anyone?

P.S

I posted here before (long ago) as 74VDC, but could not remember my password or email at the time.

[DanG]

Does keiling@yahoo.com (some characters left out) ring a bell?

[thirteen]

As I have read some on you have had problems with bearings and water. They make a bearing with three metal seals. If I remember right they are referred to as marine bearings. I put the ones I got on a shaft that runs about half of the time in the water and they have lasted four years but do require greaseing every one to two weeks. The shaft turns about 700 to 800 rpms and is 1 in. They may carry to much drag for a micro hydro system.  I got them from a boat repair shop when I was in Portland Oregon. I live in Montana, USA Just an idea to use or toss away.

[BigBreaker]

Mica shims are pretty common for non-isolated component heat sinks.  If the alternator has that sort of issue... use mica or some other mechanism.  Your delta T will be really high, so the thermal conductance doesn't need to be that great.