I am running a small (300W) crossflow turbine using a 1 hp 240V 3 phase Hyundai TEFC motor wired 1C-2C (about 800 feet from the battery, then stepped down to 60VDC via a toroid transformer, rectifier assembly and about 24,000MF of capacitance) and into an Outback MX60 MPPT controller to charge a 48VDC bank. Works like a charm. The MX60 finds the sweet spot for the turbine at any given head/load. I have a diverter on the 240VAC side set to 260VAC in case the MX60 "lets go" during the float cycle.
Rob ----- Original Message ----- From: Nando To: [email protected] Sent: Sunday, February 13, 2005 12:39 PM Subject: Re: [microhydro] AC vs. DC microhydro HUGH: I am not upset at all, and NOTHING has gone up my nose, just wanted to clarify what has been done by many. Many times the efficiency may be allowed to go somewhat lower to attain certain system or capabilities. As you have done with wind mills, that as well may need load and level controllers. Hydros Turbine may need level controllers to maintain a precise output voltage/power limitations as needed by the overall system. If you have not been successful then say it but indicate where you have not been able to fulfill the expected parameters of the system. ( same for wind mills and Hydros ). For small Turbine Hydro Electric Systems Induction motors as generators and transformer/rectifier systems NEED to have the proper load impedance that has to be not like a "ZENER" load ( Clamped Load) but like one with a variable load impedance to allow the motor/generator to retain the power product given by the turbine -- which means DO NOT overload the system or power clamp the output --.The transformer/rectifier loading needs to be adjustable like Xantrex C40 charger. Just to prove yourself : Setup the hydro with a transformer/rectifier with a small resistor in series between the battery and the charger, this resistor needs to set the maximum power drawn by the transformer/rectifier into the battery and resistor = Current^2 * Resistor + Bat_voltage*Current. Just a test -- so The CKT should have the capability to regulate the current within the limitations of the system. Small systems, many times, DO need to have a load with MPPT capabilities either DC or AC generated power. Regards Nando ----- Original Message ----- From: "Hugh" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Sunday, February 13, 2005 12:28 PM Subject: Re: [microhydro] AC vs. DC microhydro > > > At 3:32 PM -0600 12/2/05, Nando wrote: > >>Just because you have tried 3 times with induction motors and failed to >>get >>the proper results you are FOUL MOUTHING the Hundreds or even several >>thousands small hydro systems using induction motors as generators. Low >>cost, Long Lasting, Easy to implement, Easy to control and maintain. > > I am sorry, I had no intention of being foul in any way. I intended > to be helpful. If you know of a successful example using an > induction generator and a transformer/rectifier, please could you > tell me the efficiency? and suggest where I may have gone wrong? My > turbines were not stalling, and I experimented plenty with the > excitation but could never get any of them producing more than half > what they should. This is also typical of other systems of this sort > that I have heard of. > > I have had great success using induction motors (with controlled AC > output) feeding synchronising sine wave inverters, but then I have > the extra cost of the controller. I have had great success with high > voltage permanent magnet machines and transformers. Hydro power is > very easy compared to windpower. But induction motors and > transformer/rectifier battery chargers are not so easy at all. > > A heavy cable is often cheaper and more efficient than a transformer, > so I thought I ought to mention that fact. I also mentioned that he > could use either a stream engine or a multi-jet pelton on that site > and either would work well. Everything I said seems to have got > right up your nose. > > I seem to have upset you, Nando and for that I am most sorry. If I > have upset anyone else then I am sorry for that too. I only tried to > be helpful by relating my own experiences, but in future I will > probably not risk it. > > best wishes, and bye bye. > -- > Hugh > > > > > > > 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 > > > > > > > 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! 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