Constructing a Pelton Turbine

[rangerwreck]

Howdy,

Looking for any resources about constructing a Pelton wheel, something around 150kW. I was thinking myself, cast the buckets out of aluminum (you can find tons of info about aluminum casting on the web, it's very simple), and then bolting the buckets to a tire rim of the appropriate size.

However, I can't find any information on sizing the buckets appropriately! I can find force calculations, but nothing relating the flow to the size of the bucket needed.

Suggestions? Links?

Thank you,

Geoff

[jimovonz]

The size of the cup is related to the size of the jet of water that hits it. Your nozzle (that determines the jet size) is sized to flow the volume of water available at the pressure you have. The pelton cup is designed to split the water jet in two and turn the water back 180 degrees. I would say that to do this effectively the incomming water would need to be well clear of the outgoing water and follow a smooth transition along the 180 degree turn in the bucket. Obviously the water path through the bucket should not be too long to reduce friction losses. I would say that each half of the bucket should be two to three times the width of the incomming water jet with a similar depth. I have made two pelton turbines using buckets from www.ecoinnovation.co.nz. Both of these approximately follow the dimensions I have described. Obviously these cups would not be suitable for 150kW... One other piece of info that may be useful - Once you have sized your nozzle you can determine the velocity of the water leaving it. The optimum speed of the pelton bucket is half this speed.  You can use this speed to calculate the RPM of a given sized pelton wheel or alternatively calculate the size of the wheel to give max power at a given RPM.

Hope this helps!

[picmacmillan]

hi ranger....brukesfallsman has built a pelton and it is awesome..he had some help from some other folks on here ..on his the water hits the wheels on the way in, and on the way out......i have a few photo's of it on irc in my photo section there....it is a real cool machine ..he said he generates 1 kilowatt per day from a small beaver pond(stream)....he usually vacations in texas i believe, but maybe he will read this and give you some ideas...i can maybe send you some more pictures as he said it was o.k. to show them as he wasnt able at the time...his pelton is of course alot smaller than what you are looking into but i believe the wheels were made of some kind of polypropylene, polyethylene, polystyrene,poly wanna cracker or bakelight?? not sure what, but you get the picture  very cool...might ask nando?  he maybe can help you....pickster

[alancorey]

150 KW is something like 195 horsepower.  You're going to need a truck rim, or maybe something off a bulldozer, tractor or tank.  And it still needs to be balanced if it turns very fast.

There are some nice pictures of old ones at http://www.oldpelton.net but nothing that big.  That's about 500 times the wattage of what I'm hoping to run.

  Alan

[rangerwreck]

Yeah, that's why want to use a rim--I can find the specs easily enough. Any light duty truck rear end can handle 200HP+ easily enough. And a large tire balancing machine will take care of that part after I get it roughly balanced on the bench.

[Vtbsr]

Hi ranger, What kind of head and flow do you have to run such a big pelton? Data first and then design turbine.

[alterfuels]

I would check out the high pressure irrigation pumps run in reverse.  They are cheap to purchase.  They demand a constant flow rate but are commmon and cheap.  Check out www.smallhydropower.com  They make great load controls for ac systems.

[DannyB]

Ranger, if you're interested, I have a very complete chart of dia vs head for Pelton wheels. It starts at 6 inch and goes to 6 feet dia. Head starts at 20ft [8lbs] and goes up to 800ft. [348lbs]

It also lists HP and RPM. It starts out at .05 hp and goes up to 1528 HP

It lists cubic feet and miners inches too.

For example; 6 ft. wheel,,,130 ft. head [56lbs],,,478.41 cu ft 145 RPM,,,100.08 HP

Same wheel @ 800 ft. head is 1528HP and 1186 cu. ft.

A 6 ft wheel with 600 ft head puts out 992 HP @312 RPM @ 1027 C.F.

A 3 ft wheel with 600 ft head puts out 248.16 HP @625 RPM

 I also have drawings that you could scale and get your dimensions

DannyB

[crossk]

Sorry I'm a little slow, and new on here besides, but what is "irc" ? I would like to see the pictures. I am thinking of building one my self by casting the cups my self as I have access to lots of old brass but to ship something heavy out here to the Aleutians, the cost is insane. Thanks Crossk

[ghurd]

"IIRC" = If I Recall Correctly.

IIRC, My daughter told me.  

[jsparro7]

I also am very interested in viewing some of the pictures of the pelton turbine of which you speak. Can you send them or some information that would help me on my way. My email is jonathansparrott@bellsouth.net

I have numerous beaver damns and low-head systems everywhere on the property that I would like to utilize. In particular, water moving at about 30 gallons/ minute out of a pipe from behind a farm pond. Please let me know where I can see these pics. Thanks.