hello need some advice about water turbine

[sam_kellick94]

hello so im doing some research for my dad who had bought some land right next to a river and he is wanting to setup a water turbine to charge a battery bank for power for his caravan i have found a water turbine that should work on ebay

PMA Generator with Pelton Wheel for Water Power 0-240 VAC 4000 Watt Micro Hydro | eBay

the specs on the turbine are 12 VAC at 140 rpm and 200 watts, 120 VAC at 1400 rpm and 2000 watts. At 2800 rpm, 240 VAC and 4000 watts im thinking he could use a high pressure 12v water pump to spin the turbine and am going to aim to get 1400 rpm out of it which is 120vac and 2000w what i need help with is how to get the voltage down to the right amount to charge a battery bank i know i will need a 3-phase bridge rectifier to change it to dc but am not shure on what to do after that. any help would be much appreciated. thanks sam

[kenssurplus]

Sam,

Welcome to the forum. If I understand you correctly, you are going to attempt a looped water pump / turbine - alternator type config somewhat similar to what James Hardy did? See: Directory:James D. Hardy's Self-Looped Water Pump and Electricity Generator - PESWiki

If this is not what you are doing, and you are just going to use head / flow from the river to power the turbine, then to answer your question, I would vote for 3 matching step down transformers tied together in wye, then to a 3 phase bridge rectifier outputting DC into your battery banks. The batteries will keep the voltage locked down to their charge state. The only issue here is overcharging of the batteries and boiling the batteries dry. This can be prevented by using a dump load controller and a dump load such as this:
Diversion (Dump) Load Controllers

If indeed you are attempting a looped water pump / generator system, then you would need to put most of the generated energy back into the pump, and only take out a very small portion to charge the batteries. This scenario would entail either a microprocessor to watch the voltage and dump a cap to the load, or you could possibly devise a mechanical governor to disconnect the load if the rpm drops - Much harder to do.

Either way the unit from Ebay looks nice. Good luck whichever way you decide to go.

[sam_kellick94]

Sam,

Welcome to the forum. If I understand you correctly, you are going to attempt a looped water pump / turbine - alternator type config somewhat similar to what James Hardy did? See: http://peswiki.com/index.php/Directory:James_D._Hardy's_Self-Looped_Water_Pump_and_Electricity_Generator

If this is not what you are doing, and you are just going to use head / flow from the river to power the turbine, then to answer your question, I would vote for 3 matching step down transformers tied together in wye, then to a 3 phase bridge recifier outputting DC into your battery banks. The batteries will keep the voltage locked down to their charge state. The only issue here is overcharging of the batteries and boiling the batteries dry.

If indeed you are attempting a looped water pump / generator system, then you would need to put most of the generated energy back into the pump, and only take out a very small portion to charge the batteries. This scenario would entail either a microprocessor to watch the voltage and dump a cap to the load, or you could possibly devise a mechanical governor to disconnect the load if the rpm drops - Much harder to do.

Either way the unit from Ebay looks nice. Good luck whichever way to go.

hello thanks for the info i was planing on doing the looping system but if its going to draw to much power there might not be much point this was the pump i was going to use its a small one but high pressure
12V DC 65PSI 0.45Mpa 3L/min Diaphragm Water Pressure Pump High | eBay
i dident think it would draw that much power and isent 2000w watts and 16amps more than enough to charge the batteries and run the pump also could you tell me whare i could get hold of the transformers you are talking about

[kenssurplus]

Your pelton wheel has a certain range of required head / flow for it to operate efficiently.
From Wikipedia:

Pelton wheels are the preferred turbine for hydro-power, when the available water source has relatively high hydraulic head at low flow rates, where the Pelton wheel is most efficient. Thus, more power can be extracted from a water source with high-pressure and low-flow than from a source with low-pressure and high-flow, even when the two flows theoretically contain the same power.

This needs to be matched to your pump capacity. There was no head / flow paramaters given for your turbine, so you would have to look up similar sized pelton turbines to guess. I would rather doubt that 3 L / min @ 65psi would provide the 2000 watts that you are hoping for.
Again from wikipedia:

The smallest Pelton wheels are only a few inches across, and can be used to tap power from mountain streams having flows of a few gallons per minute. Some of these systems use household plumbing fixtures for water delivery. These small units are recommended for use with thirty meters or more of head, in order to generate significant power levels. Depending on water flow and design, Pelton wheels operate best with heads from 15 meters to 1,800 meters, although there is no theoretical limit.

Here is a micro hydro calculator to match everything up:
http://www.energyalternatives.ca/con...oHydroInfo.asp

[kenssurplus]

Sam,

You aim to get 120 VAC out of your turbine. So you would want three 120 VAC to 15 VAC transformers. I would choose the VA rating of the transformers somehwere in the range between 600 to 1000 VA. A 30 to 60 amp 12 volt battery charger would work (not a pulse charger but one with a large transformer). How I would do it is to use three identical units and tie all the 120 volt neutral lines together, and connect the hot line of each charger to a different line of the 3 phase output from the alternaltor.

As always, electricity is dangerous. I don't suggest you do any of this yourself. So have a qualified electrician install and set up your system.