Hi, (Mechanical engineer student in Guatemala). You are probably on the right track, but for better help you might have to answer some more questions:
1. Water supply: a) How much water does the pump supply? (gpm or liters/sec) 2. Generator: a) RPM ? (needed to calculate diameter of the Pelton wheel) b) Voltage, c) Rated Power? (not essential, just curious) Anyway, the following story might be of some interest to you: Back in the sixties when I was in primary school (probably around 11 years old), I and my (older) classmates had great interest in all kinds of mechanical and electrical experiments and one of our best evening project was to build a Pico Hydro system somewhat similar to the one you are working on. We had zero budget so this is what happened. The hub of the wheel was approximately 6-8cm diameter, a plastic wheel taken from a toy car. The buckets were made of same type of plastic material cut out of something like a 5litre AntiFreeze Container. This material was then about 1-2mm thick. Nowadays, AntiFreeze containers are much thinner here but other and larger containers may have thicker side walls. I am no expert regarding plastic material, but this probably was PE. To make a tool to form the buckets, we taped two bicycle frontlight bulbs together (regular flashlight bulbs were in our opinion too small). Then two holes were drilled side by side in a piece of wood to press the bulbs into. The plastic material was cut a bit oversize, then heated above a candle until soft and the buckets formed by pressing the soft plastic with the bulbs into holes mentioned. If we pressed too hard, the bulbs got stuck in the plastic material and we broke one or two, but oiling them lightly did help. Then excess material was trimmed of with a knive and the buckets attached to the wheel hub by "welding" with a soldering gun probably not healthy to breath the fumes of molten plastics but we´re all still alive. This of course only produced circular buckets which is not how a true Pelton should be. You could probably try to make a better mould with the correct profile for real Pelton buckets. Total diameter of the wheel with buckets was some 10-12cm. At last the wheel was put on a 6V bicycle generator (the tire driven type), put in some box, which I do not remember much about, connected to a bicycle front light and a water jet directed at the buckets. The nozzle was a porcelain distribution boxe fuse with approx. 3-4mm hole and outside diameter fitting the hose connected to the tap water in the basement. Our water supply was somewhat unusual as it was taken from the penstock of a 220V DC Micro Hydro that supplied electricity to the farm house where our school was at the time. I do not know the head, guess it was approx. 50m. The setup turned quite fast and produced plenty of power, I have never seen so bright bicycle lights. This was not a school project, just our hobby, no real measurements were made regarding power output or efficiency. We did not run the turbine long enough to know the lifetime of it, but I do remember that all buckets remained fixed to the wheel after quite some testing and some burned out front light bulbs. Also, we had other projects waiting........... Our next evening project was a carbon arc light with rods taken from D-type dry cell batteries, which we put inside a small clear glass bottle and connected directly to the 220V DC Mains. (WARNING: DO NOT TRY THIS ONE AT HOME!) That evening we managed to melt the glass bottle in a matter of seconds and produce a very-very bright arc, more like a sun, that made our Pico Hydro lights look like mere candles. Then some grown up people on the floor above noticed that the ligths went out, but instead some blue/white rays were shooting out the basement window, illuminating the clouds and started interfering.......... ;-) Best regards. Thor. -------------------------------------------------------------------- Thorhallur Ragnarsson Electronics Technician/Instructor Holtakoti Verkmenntaskolinn Akureyri IS-641 HUSAVIK Eyrarlandsholti Iceland IS-600 AKUREYRI [EMAIL PROTECTED] Iceland [EMAIL PROTECTED] [EMAIL PROTECTED] http://www.simnet.is/holtakot http://thor.vma.is/not/thor -------------------------------------------------------------------- At22:37 14.9.2005 +0000, kunoserg1703 wrote: >Hello, I just entered this group; I´m a mechanical engineer student in >Guatemala and I was wondering if any of you could help me with this >project I´m doing. > >The project is for a University course (Fluid Mechanics); I have to >design and build a hydro-turbine to produce power. There are some >limitations to be considered, and here´s where I find trouble: > >*there´s a limitation budget of $25.00 >*I have to use a pump with a net head of 15 m. >*I have to adapt my turbine to a 1 cubic feet box, already >constructed. >*I have two weeks. >*I have to build all the stuff, and try to use as less money as I can, >since the grade is going to be based not only on the power output, but >on the money saved. >*the generator has already been chosen > >I have already decided to build a pelton turbine, but I´m having >trouble to determine how to make the buckets, and what cheap material >to use. I was thinking to use a mold and make them with plastic, but I >don´t know how. If any of you have already done a project like this, >any help would be welcome. Thanx, hope to hear from you. > > ------------------------ Yahoo! Groups Sponsor --------------------~--> Get fast access to your favorite Yahoo! Groups. 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