Arild Jensen wrote: > > > REPLY > I have begun researching wind mills recently and find many manufacturers are > not particularly forthcoming as to internal details of design. > > The new permanent magnet designs rely on the battery to regulate the output. > Once full voltage is measured at the terminals some kind of regulator dumps > the output into a diversion load.
This is NOT how Air Marine units work! They sense output voltage on the output cables, not the battery (of course if the unit is connected to the battery and good size cables are used, then the output of the unit and the battery voltage will be very close). Then once the voltage is high enough the unit stabilzes the output voltage via the switchmode regulator and controls the blade speed to also regulate the output by using the "Z" (impedance) of the windings to act as a type of electronic braking for the blades. It does this by controlling the phase of voltage fed back into the windings so that a constant impedance through the windings is obtained and a current is created that produces a counter emf that opposes the torque of the blades. The result is a very efficient form of regulation. I think that the newer models do indeed produce 'multi stage' output also. But even the older models could be 'fine tuned' with an external regulator, although if you also have a solar panel, it is not needed to obtain a 'float' charge. Then you only need to worry about overcharging. I get around that by always leaving small ventilation fans on, which run faster and draw more power as the voltage rises and effectively prevent overcharging from the solar panel. > This not always the best way to complete > the charging of lead acid batteries. There should be a float stage to remove > the last vestiges of lead sulfate. On the other hand leaving the charger > connected for too long will cause gassing and lead to electrolyte loss. > Worst case being a sealed AGM or Gel battery bank which could suffer > permanent damage from over charging. > > Automotive alternator designs would be better but these automotive > alternators require a fairly fast rotor RPM to be really effective. Now we > need a speed up ratio similar to what we have in a normal engine > application. > Does anyone have some knowledge of which models ( if any) do have such a > speed up incorporated in the design? > Again, auto alternators make poor power units for marine wind generators when compared to modern perm mag types, because (as you note) they have an incorrect shaft or wind speed/output curve to start with, but auto types are *ALSO* heavy, low powered, and in-efficient when compared with such units as Air Marine uses...my 'old' wind genny weighs 11 lbs including the internal regulator (less than some auto alternators alone!), and will make over 30 amps continuously (rated, and I have seen it do so) for as long as the wind blows that high or the batteries need it (new models this size go to 40 amps I am told), and it will produce more power than I can use even in light winds underway. What's more it does not need 'tending' and requires very little maintenance. > Yes I am aware that such a feature would also require a higher wind speed to > start turning. Perhaps someone did have a design to compensate. > Yes, and then it would then need to 'furl' at lower wind speeds, otherwise > you are producing a lot of power that will overheat the 'dump' load at higher > wind speeds, making run-away very likely. Also the output windings will be > getting very hot. If you try to get around this input windings heat problem > by lowering the field windings voltage, then you will have run-away even > sooner. For less $ you could get an old perm mag motor (they use to use tape drive motors out of big video tape decks) that would make a far better wind genny. Even then you need to effectively solve regulation (a motorcycle regulator would do well here I bet, but they are not very efficient), furling or braking, and blade/speed issues. Why re-invent the wheel? Even if you DID get a genny such that you could repair anything on it with simple parts and tools, chances are it would need that much more often than 'store bought' models, and repairing it would not likely be cheaper or easier long term, either. The only thing you would gain with this approach is the opportunity to tinker with the wind genny every so often, it seems to me. Fine if that's how you want to spend your time.-Ken _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://www.liveaboardnow.org/mailman/listinfo/liveaboard To subscribe send an email to [EMAIL PROTECTED] To unsubscribe send an email to [EMAIL PROTECTED] The archives are at http://www.liveaboardnow.org/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
