Pretty elegant Joe. For battery charging, triggering off the voltage is way less work than monitoring frequency and works just as well. I built my own dump (using the design published in an old Mother Earth News magazine) running into either a 240V/500W baseboard in the dining room or the hot water heater. However, I may get one of those Morningstars as a backup. A properly- functioning diverter is a critical component in our type of hydro-generator setup.
Rob Quoting Joseph Hartvigsen <[EMAIL PROTECTED]>: > > > > > 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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