Hello, Very good description of your system. Very interristing for me in direct application ! Thanks a lot
I've got the same system of your I don't use all the power i can use because of the dumps load who are limited in power. The dump loads are standard 240V 3000W water heaters on a pressure tank.(3 phases 400V/240V standard electric boiler) But y use them in 24V so only 300W is used. If i use them on the 240V line, i will dump 9000W (only 1300W are OK for me) I've got the solid state relays in stock ! and the resistors too ! (3 phases relays with 3-32V DC command( internal 40VDC protection) Carlo gavazzi or crouzet) So i will try this arrangement soon. My generator is an old induction motor used in generator with capacitors. What is your ? Regards Eric ----Message d'origine---- >A: [email protected] >De: "Joseph Hartvigsen" <[EMAIL PROTECTED]> >Date: Fri, 16 Dec 2005 20:25:11 -0000 >Sujet: [microhydro] Re: Alternator recommendations > >I agree with Rob that for small systems it is much simpler and more >reliable to regulate the power rather than the water flow. Most of >these small systems will be used for battery charging, but the power >may be delivered as AC at higher voltage. In such cases there is an >easy way to regulate the system by putting the dump load across the AC >line rather than the DC. > >Rather than deal in general terms I'll explain how my recently >modified system is set up. > >Power comes from the turbine driven induction motor as 3 phase AC at >about 167V. > >[A side note: It is at 167V because it then goes to 3 transformers >setup as 240V (delta) primaries and 32V wye/star secondaries then to a >3 phase bridge rectifier with the output connected to a 48V (56V >typical) battery bank. Unlike single phase, where the RMS voltage of >the rectified sinewave DC output is exactly the same as the RMS AC >input, in 3 phase the DC output voltage is 1.35 times the leg to leg >AC voltage. So, the battery clamps the rectifier output to 48-56V >depending on state of charge, which means the AC phase to phase input >is ~52/1.35 = 38.6Vac, which means each of the transformer secondaries >forming the wye/star is 38.6/sqrt(3) = 22.3Vac, that means the >primaries are 240*22.3/32 = 167V. If I had used nominal 24V output >transformers in wye to the 3 phase bridge, the primaries would run >closer to the rated voltage. 24*1.35*sqrt(3) = 56.1V ] > >I used a solar charge controller, Morningstar TS-45 and configured it >in diversion load mode with its inputs connected to the battery +/- >and outputs connected to two resistors in series. These resistors can be >relatively low wattage, sized for only 30-50mA. For example with 60V >peak battery equalization voltage, split across two resistors 50mA*30V >= 1.5W and 30V/0.05A = 600ohm. So you could go with two standard >value 680 ohm or even 1k-ohm resistors rated at 5W or 10W connected in >series and connected across the TS-45 load +/- terminals. Clearly this >won't dissipate much power, but it does provide a 24-28Vdc signal >between the load (-) terminal and the point between the two resistors >which I use to fire AC solid state relays (SSRs). If you have a 12 or >24V battery bank you can fire the 3-32Vdc triggered type AC SSR >directly from the TS-45 output terminals. If you have higher than a >48V battery bank use more of the resistors in series and take the SSR >trigger (+) signal from the opposite lead of the resistor connected to >the (-) terminal. > >Now, whenever the battery bank voltage is at the control limit, the >TS-45 in trying to dump power actually just sends a signal to trigger >the SSRs. The SSRs are connected to AC line voltage from the hydro on >one side, and a load resistor on the other side. You can find these >relays rated to 25A (using a heat sink) at 240V for about $20 each at >most electrical supply places. > >I had previously used some old oven and drier heating elements, but >they took up too much space on the wall. So I put three 300W 16ohm >edgewound and enamel coated resistors in series across the 167V from >the hydro. That will dump in my case ~580W, but it is easy enough to >size these resistors to dump what power you need at the generator line >voltage. > >I purchased the resistors from digikey.com The 300W version are $16.48 >each, part number FVE-300-xx (xx is resistance in ohms from 0.5, 1.2, >2.0, 5.0, 8.0, 10, 12, 16, and 20). A larger 1000W resistor (black >silicone finish rather than enamel coated) is available for $51.50 >each, part number FSE1000-xxx (-.25, .50, 1.0, 3.5, 4.5, 10, 15). Both >also have a mounting kit available. Of course if you have a useful AC >load of appropriate power and voltage rating that can be connected and >disconnected such as a water heater use it. > >So, in simple terms, the PV load controller senses battery voltage, >triggers SSRs which connect an the AC diversion load across the lines >from the hydro. > > Joe > > http://h-hydro.com > > >--- In [email protected], [EMAIL PROTECTED] wrote: >> >> A quick general note regarding regulation. It is my experience that >in smaller >> systems regulation is best done at the electrical output end rather >then water >> intake end. A power diverter using IGBT or TRIAC power elements, or >even >> relays, is by far the cheapest and most reliable way to govern the >output of < >> 5 kilowatt output systems. In the < 100 volt range these units are >available >> off the shelf from many vendors, while the 120V and up systems are >more costly >> and somewhat harder to to source. At the end of the day they are >still a better >> investment if only for the reason that you might still want one even >with a >> water flow diverter installed, in case the valve sticks open. >> >> Rob >> >> >> >> Quoting tom kasmer <[EMAIL PROTECTED]>: >> >> > >> > >> > >> > >> > >> > >> > using a PM motor as a generator has the following >> > >> > tenet. It has >> > >> > no regulation mechanism other than shaft speed, so >> > >> > here's what I suggest. You could rig up a smart bypass >> > >> > of the flow to regulate the speed so as to regulate >> > >> > the output power. Im sure that a magnetically coupled >> > >> > rotor excitation will indeed be expensive. >> > >> > Having a lot of experience in the fields of >> > >> > electricity and magnetism, unless this fancy generator >> > >> > has a few successful years >> > >> > of use in the field, I would stay away from it. You >> > >> > will have little or no recourse if it fails since is >> > >> > not in a car. Tom >> > >> > >> > >> > --- williameverettstone <[EMAIL PROTECTED]> wrote: >> > >> > >> > >> > > Thanks for the reply. >> > >> > > >> > >> > > 50gpm is the minimum flow even in times of drought. >> > >> > > >> > >> > > Several formulas on the net showed we could expect >> > >> > > to produce about 20 >> > >> > > watts w/ 50gpm and 4-5' head. This equates to 1.6 >> > >> > > amps at 12 volts. I >> > >> > > figured 1-1.5 just to be realistic. >> > >> > > >> > >> > > Thanks for the advice on PM motors, I'll check them >> > >> > > out. Since posting >> > >> > > I found that Delco has come out with brushless >> > >> > > alternators available >> > >> > > in 12, 24 and 48 volts. I'm waiting for a quote on >> > >> > > one now, rewound to >> > >> > > produce at lower RPM. I expect it's going to be too >> > >> > > pricey. >> > >> > > >> > >> > > Thanks again. >> > >> > > >> > >> > > >> > >> > > >> > >> > > --- In [email protected], tom kasmer >> > >> > > <[EMAIL PROTECTED]> wrote: >> > >> > > > >> > >> > > > >> > >> > > > my experience witn GM alternators is that the >> > >> > > brushes >> > >> > > > will last >> > >> > > > about 150,000 miles + or -. That is a half year of >> > >> > > > steady driving. The alternator is subjected to >> > >> > > > underhood temperature extreemes and wild >> > >> > > > accelerations. In an outdoor enclosed housing, >> > >> > > > running at a fairly constant speed, you might get >> > >> > > a >> > >> > > > year of 24/7. >> > >> > > > Your 1-1.5 amps sounds low. How did you get that >> > >> > > > number? As far as PM generators, any PM motor will >> > >> > > > work nicely as a generator. >> > >> > > > 4 feet of head is only 2 psi of pressure. How much >> > >> > > > total flow >> > >> > > > does the creek have worst case drought time? Is >> > >> > > that >> > >> > > > the 50 gpm number? If you are limited to this >> > >> > > level of >> > >> > > > power, that is about >> > >> > > > 20 watts best case with an automotive generator. >> > >> > > You >> > >> > > > might better spend your budget on a photovoltaic >> > >> > > array >> > >> > > > and settle for >> > >> > > > daylight only solar power with less hassle. Im not >> > >> > > an >> > >> > > > expert in microhydro power so others may do >> > >> > > better. >> > >> > > > Tom Kasmer >> > >> > > > >> > >> > > > --- williameverettstone <[EMAIL PROTECTED]> wrote: >> > >> > > > >> > >> > > > > Hi All, >> > >> > > > > I have a situation with minimum 50gpm flow year >> > >> > > > > round (I have been >> > >> > > > > measuring for 5 years, through drought and >> > >> > > different >> > >> > > > > seasons). >> > >> > > > > >> > >> > > > > My wife and I are planning to rebuild the >> > >> > > remnants >> > >> > > > > of a small dam on >> > >> > > > > the creek which would provide about 4' head. We >> > >> > > > > estimate we could >> > >> > > > > generate 1 to 1.5 amps here. >> > >> > > > > >> > >> > > > > We are on a budget, and a prebuilt micro hydro >> > >> > > unit >> > >> > > > > is out of the >> > >> > > > > question, at least the ones I've seen so far >> > >> > > ($1,000 >> > >> > > > > and up). >> > >> > > > > >> > >> > > > > If we were to use an off the shelf auto/truck >> > >> > > > > alternator w/ brushes, >> > >> > > > > how long can we expect the brushes to last >> > >> > > running >> > >> > > > > 24/7? Are PM >> > >> > > > > alternators available, and how pricey are they? >> > >> > > > > >> > >> > > > > My second dilemma is predicting the best turbine >> > >> > > > > type and size, and >> > >> > > > > pulley ratio to obtain the highest RPM at the >> > >> > > > > alternator with the >> > >> > > > > available water flow. Is there a method to help >> > >> > > make >> > >> > > > > these decisions? >> > >> > > > > If we fabricate some sort of squirrel cage type >> > >> > > > > turbine, how do I >> > >> > > > > decide the optimum radius of the unit? >> > >> > > > > >> > >> > > > > Thanks so much for any help! >> > >> > > > > Bill > > > > > > > > >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! 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