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Posted by Bob F on March 25, 2008, 12:19 am
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>
>>
>>> Yup!
>>>
>>> Today I spent some time trying different nozzles just to see if I
>>> could wrangle out those last few RPMs needed to get past 12 volts ..
>>>
>>> I bored two out to 3/8ths and dremmeled the crap out of them,
>>> finishing the interior with some fine gauge steel wool wrapped around
>>> a dremel shaft and polished it till the battery died on the tool. I
>>> made sure it was a smooth angle to the tip and got rid of all the
>>> scratch marks from the drill bit.
>>>
>>> Put them in and just ran the hydro with a multi-meter and was getting
>>> around 7 volts with a single jet. Pretty sweet .. the most I ever
>>> got before was around 5.5. With both jets on and with some fiddling
>>> with the angles I hit 13!!
>>>
>>> So I turned connected them to the batteries and whadya know.. its
>>> charging. The battery bank is at 12.4 and when I hit the switch to
>>> complete the circuit the alternator comes under load and keeps on
>>> spinning!!!
>>>
>>> So thats that then. Now just have to keep tweaking things to gain
>>> more performance. I might bore some out a bit bigger and see how
>>> that goes. The nozzles i'm using don't have much room left .. any
>>> larger bores and i'm risking going through a side wall, but they're
>>> only like 2 bucks each so its not a huge deal if I screw one up.
>>>
>>> speaking of which think i'll have to get to town and buy a few more
>>> to play with.
>>>
>>> Hey
>>>
>>> I can't thank all of you enough for the advice and telling me i'm
>>> doing something bone headed once in a while -- its been a huge help.
>>>
>>
>> With the nozzles bored out to 3/8 inch, unless youve increased the
>> feed tubes 2 or 3 time in diameter, you are probably losing a lot of
>> velocity in the feed tubes. What you need from what I read is
>> velocity, to spin the wheel faster.
>>
>>
>
> its interesting I did a test with some smaller nozzles and although the
> velocity is faster, they do not turn the wheel as fast as those with the
> larger bore.
>
> There must be some kind of relationship of the wheel to the water such
> that the larger bore catches the wheel better or something like that --
> maybe the area (stream size) must be a certain volume in order to impact
> its force uppon the wheel ??
>
> In any case, these new bores show the greatest RPM compared to the other
> so i'll stick with them I guess.
>
> But like I said in the other post, the windbluepower guys are going to
> install a different stater that should get me in the right voltage range
> given the RPM i'm getting now.
>
> hopefully that will get me into the juice before summer comes!!
>
Without a doubt, the stator change sounds like an excellent approach. It
should, if properly done, enable you to get signifacantly more power out at the
lower speed you are attaining. Looking at the charts of the two generators, it
looks like you are getting slightly more than 1000 rpm. That looks like the new
generator curve will put you exactly where you you want to be voltage wise,
according to the pelton wheel design theory described by others here.
The larger nozzle will definately give you more torque, which should result
in more current at any given speed. The no-resistance speed will be higher with
faster water speed, which will be somewhat dependent on the size of the feed
tube. If the feed tube in insufficiebtly larger than the nozzle, the resistance
which reduces speed will be higher. When optimizing this system, that would be
something to look at.
The fact that your larger nozzle made a big difference in the unloaded
voltage suggests to me that the friction and other losses in the generator are
significant. These are probably going to decrease as the generator "breaks-in".
I have a hose "blaster" nozzle I acquired many years ago which could be a good
prototype for an adjustable nozzle. It has an internal rubber tube outlet nozzle
which can be constricted by turning an outer adjustment. It would produce a
solid stream as big as 1/8" in diameter, and adjust down to a single jet so
small as to be practically invisable. It's great for party tricks with the small
jet. IF such a thing is made in a larger size, it could be very good for
optimizing water flow for seasonal water supply and power needs.
As always, I'll be looking forward to your next report.
If you were nearby, I'd bring the homebrew.
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