Hi ([EMAIL PROTECTED]) Quick answers to your questions:
1) Can I use it for my site with a reasonable efficience only reducing the jet size? Yes, I would think so. 2) If no, which are the reasons? (no problems) 3) If yes, which should be the new optimal jet diameter? According to formulas suplied by Eilrem ([EMAIL PROTECTED]) the jet velocity: v = sqrt(2gh) = sqrt(2*9.81*106)=45,6m/s the jet area: A = Q / (1000v ) = 15/(1000*45,6)= 0,00000329m^2 and diameter: d = sqrt(4A / pi) sqrt(4*0,00000329/3,1416)= 0,0204m so: the jet diameter for 15l/s at 106m head is 20,4mm and the diameter for 30l/s at 106m head is 28,8mm 4) What may be the efficience lack? Not very great, the buckets are a bit big, causing some drag, but you should get good efficiency. 5) What about the resulting RPM ratio at runner shaft? This is probably the most important change if you have changed the head. Theoretically: RPM = 42.3*sqrt(h)/D = 42.3*sqrt(106)/0,45 = 967RPM in practice 5-10% less, so I would say around 870-900RPM 6) How many electrical watts can I expect? Theoretical power for 30l/s and 106m is 31,2kW Efficiency for this size of Pelton turbine should be 70% or more so I would expect electrical power in the range 20-25kW (15l/s gives roughly half of that) Other comments: You seem to have a generous size of pipe Head loss for 15l/s in 150mm dia. 360m long PVC is only approx 1.5m and the loss for 30l/s is approximately 5m. You would want to use a needle valve to control the jet size and some kind of pressure relief valve to prevent accidents if the needle valve is blocked suddenly by some reason; foreign material, mechanical failure or unsafe closing speed. (42tons of water moving at up to 6km/h in a pipe simply will not stop suddenly and can build up great pressure and do horrible damage to people, pipes or machinery) Questions: (1) Where in the world are you located? (2) Do you want 50Hz or 60Hz and at which voltage? 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 -------------------------------------------------------------------- >>> [EMAIL PROTECTED] wrote at 4.10.2005 13:42 >>> Dear microhydro members... I'm thinking to purchase a well made used pelton turbine from somebody who never installed it. Obviously, the problem is that the machine was designed for another head/flow parameters different than mine. Machine data: Runner diameter - 450mm (measured at the middle of the buckets) Max buckets wide - 120mm Jet diameter - 45mm New site data: Gross head - 106m Existing pipe - 150mm diameter PVC / 360m Summer flow - 15 L/s Winter flow - 30 L/s My questions are... 1) Can I use it for my site with a reasonable efficience only reducing the jet size? 2) If no, which are the reasons? 3) If yes, which should be the new optimal jet diameter? 4) What may be the efficience lack? 5) What about the resulting RPM ratio at runner shaft? 6) How many electrical watts can I expect? And any others comments will be wellcome... Thanks a lot in advance! __________________________________________________ Correo Yahoo! Espacio para todos tus mensajes, antivirus y antispam ¡gratis! Regístrate ya - http://correo.espanol.yahoo.com/ ------------------------ Yahoo! Groups Sponsor --------------------~--> Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/FGYolB/TM --------------------------------------------------------------------~-> Does your company feature in the microhydro business directory at http://microhydropower.net/directory ? If not, please register free of charge and be exposed to the microhydro community world wide! NOTE: The advertisements in this email are added by Yahoogroups who provides us with free email group services. The microhydro-group does not endorse products or support the advertisements in any way. More information on micro hydropower at http://microhydropower.net To unsubscribe: send empty message to [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/microhydro/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
