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#Post#: 637--------------------------------------------------
NessProjects Boost Circuit
By: nessprojects Date: October 25, 2013, 4:18 pm
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Here is the "Buck-Boost" schematic that I have used on my small
HAWT for many years.
#Post#: 640--------------------------------------------------
Re: NessProjects Boost Circuit
By: nessprojects Date: October 25, 2013, 7:08 pm
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The circuit is simply a Cockcroft–Walton doubler in parallel
with a full wave bridge.
Tests were done using 1000uF caps and found to give a couple of
amps but the idea is to load the turbine slowly which will allow
the turbine to gain speed and not to stall.
Caps C1 and C2 need to be chosen carefully to suit your own
turbine but it is easy to get carried away and load it too much.
The smaller the caps the lighter the amp draw until full power
can be drawn straight through the bridge.
PS CG Love the speed controller, working on similar myself.
#Post#: 642--------------------------------------------------
Re: NessProjects Boost Circuit
By: nessprojects Date: October 25, 2013, 9:25 pm
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Glad you like it.
I have used the same circuit for a few years now with no
problems at all. I used 330uF caps in my small HAWT which now
starts charging in low wind speeds.
I did build a 3 phase booster for my 300W PMA, that did take
some figuring out, but I did get there in the end.
The full wave bridge takes care of the negative side as you are
not requiring minus voltages.
PS.
8.79V Doubled = 17.58 multiplied by 1.414 (Square root of 2)
should give 24.8V DC OC minus rectifier voltages of coarse.
Hope this helps and good luck.
#Post#: 649--------------------------------------------------
Re: NessProjects Boost Circuit
By: lynx wind Date: October 26, 2013, 10:01 am
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NessProjects,
I tried the circuit with the single phase Gull 40 alternator.
Works beautifully. I wondered if the circuit would bog down the
alt or make it feel bumpy or eliminate the pulse charging I
like. Very smooth from about 60 rpm cutin on up to heavy
charging cutin at about 180 rpm. I used 220uf electrolytic
capacitors. The circuit is about the size of two postage
stamps. Just a hand spin I brought an 11.85 volt battery up to
12.85 volts in 30 seconds. Very simple and convenient way to
fine tune an otherwise low volt output alternator. This would
be a good way to use heavier wire for low resistance and still
get charging at low rpms.
Thank you!
A lot of clever people on this forum : )
#Post#: 650--------------------------------------------------
Re: NessProjects Boost Circuit
By: lynx wind Date: October 26, 2013, 10:13 am
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Here's a picture of the circuit. Components are just twisted
together for testing.
[attachment deleted by admin]
#Post#: 651--------------------------------------------------
Re: NessProjects Boost Circuit
By: lynx wind Date: October 26, 2013, 1:00 pm
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I made this video to show what the Nessproject's circuit does.
Very simple to do and effective.
HTML http://youtu.be/31niHiaXWfs
HTML http://youtu.be/31niHiaXWfs
#Post#: 652--------------------------------------------------
Re: NessProjects Boost Circuit
By: nessprojects Date: October 26, 2013, 3:23 pm
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Many thanks Lynx for the video. :)
I don't think it will eliminate the single phase peaks, I have
never connected a scope up to it but reckon It will just follow
them at twice the voltage but at the limited current.
Experimentation is required to get the caps to suit the
individual turbine.
Best wishes to all . . . . . NP
#Post#: 656--------------------------------------------------
Re: NessProjects Boost Circuit
By: lynx wind Date: October 27, 2013, 8:31 am
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Crazy Guy mentioned not needing diodes D5, D6 as discussed by
members of the BackShed forum. I can see this in the schematic.
My thought was it is very convenient to use the 25 amp 50 volt
common bridge rectifier package with heat sink and just tack on
the doubler. But then I am reading most of the current goes
through the doubler and can overload the capacitors. I am
unclear on why that would be. Can someone clear that up?
#Post#: 657--------------------------------------------------
Re: NessProjects Boost Circuit
By: nessprojects Date: October 27, 2013, 10:23 am
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@ Lynx
If you were to remove D5 and D6 from the circuit then all
current would have to pass through the doubler, This would be
good if your turbine could not get to cut-in speed easily but
then you would have to increase cap size to handle the current
flow.
If the turbine can get to cut-in in a good wind then D5 and D6
start pushing current through therefore bypassing and taking the
strain away from the doubler.
Note: The doubler is always going to push current but how much
depends on the value of the cap.
Try lowering the cap size down to say 100uF then put 2 amp
meters in. (One from the doubler to battery and the other from
the bridge to the battery), This will show what each section is
doing.
Hope this is of help, NP
#Post#: 658--------------------------------------------------
Re: NessProjects Boost Circuit
By: nessprojects Date: October 27, 2013, 10:47 am
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Here is a simulated scope reading of the circuit at around
200Rpm: Blue is from the bridge and red from the doubler.
[attachment deleted by admin]
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