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#Post#: 3047--------------------------------------------------
Seagull 175 Alternator
By: lynx wind Date: May 31, 2014, 12:24 pm
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The magnet plate and one test coil are done. The coil is a "two
in hand" 18 awg (15 awg equivalent) 100 turns .4 Ohm coil. What
I do is calculate before hand what I think the OCV will be and
then test one coil. There are six coils and 12 magnets for this
alt. The resistance and voltage of one coil is multiplied by
six. Then I make adjustments before making a stator.
Procedure: Mount magnet plate and one coil. Turn crank and
watch Hz meter to get to 100 rpm. Make notes of voltage to a
capacitor, and average by eye for RMS.
This alternator will be capable of 12-24 volt charging by
switching some wires around, and will have a resistance of
either 2.4 Ohms or 4.8 Ohms It will be well suited to a battery
bank of two deep cycle in parallel. We want the stator
resistance to roughly match the resistance of the load.
The results of today's test, Open Circuit voltage
100 rpm
1.65 volts peak or 9.9 volts peak for six coils
1.10 volts rms or 6.63 volts rms for six coils
We don't want direct cutin below 1 tsr. At 12 mph wind the
Seagull 175 turbine needs to be doing 150 rpm to be at tsr 1.5
at 150 rpm voltage should be 9.9 volts rms with peaks of 14.85
volts. This means the turbine wont be loaded too much in winds
below 12 mph. The boost circuit will handle winds below 12 mph
where the watts are between 0-15.
#Post#: 3048--------------------------------------------------
Re: Seagull 175 Alternator
By: happygolucky Date: May 31, 2014, 3:06 pm
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very cool......lynx i had to go to my glossary of terms to
understand...you should have some for the novice individuals
such as i.. i refer to a glossary so i can understand...
what is two in hand not on my terms.. i assume is two 18awg
wires fed in ratio winding to get 12v & 24v the way you explain
it the guess at the Open-Circuit Voltage onto the one coil then
you tune the output so TSR is above 1 or better i don't want to
sound like a dummie ..
that's cool ..making ac power...rectifying to dc.
happy
#Post#: 3050--------------------------------------------------
Re: Seagull 175 Alternator
By: lynx wind Date: May 31, 2014, 3:33 pm
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Learning is deeper when it's a bit uncomfortable. Makes the
gears in your head turn.
"2 in hand" or "4 in hand" refers to how many strands are wound
on the coil at one time. Several small wires fit better (more
turns) than one big wire. Also by bringing each wire out, you
can change the output after the stator is cast. Parallel the
coils for low resistance low voltage, series for high voltage
higher resistance. Resistance is bad, but a reality. We want
it as low as we can get it. The 3/8" thick magnets are a few
bucks more but they make a huge difference. Really this alt can
probably do 400-500 watts. I just don't want to over-promise.
RMS - root mean square refers to the average voltage from a
sine wave ripple. Peaks are higher, but smoothed is about 2/3
of peak.
TSR - tip speed ratio, measures if the blades are turning faster
than the wind
Rectified - AC to DC voltage
#Post#: 3051--------------------------------------------------
Re: Seagull 175 Alternator
By: happygolucky Date: May 31, 2014, 4:48 pm
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learning is s a fact of life for me...thank you..i do use the
net for terms an study ,you physics majors throw the terms an
jargon around.. its hard to keep up some times.. so much to
learn.. thank you for your explanation,my wheels are spinning..
cool little site an still
learning some of math.. in TSR
HTML http://en.wikipedia.org/wiki/Tip-speed_ratio
HTML http://www.otherpower.com/glossary.html
#Post#: 3053--------------------------------------------------
Re: Seagull 175 Alternator
By: nessprojects Date: May 31, 2014, 6:53 pm
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@Lynx
I think the resistances are pretty good, I know how hard it is
to get low resistance and high voltage in such a confined space
(Been there and wore the t-shirt). Only comment really is was
the air gap at a sensible spacing because I have done tests like
this before with 1 coil and been disappointed with the finished
product due to trying to get minimum gap on initial testing in
respect to the real world. (If you know what I mean).
It is all looking very promising and definitely do like the
choice of voltage output. Thanks for the testing.
#Post#: 3055--------------------------------------------------
Re: Seagull 175 Alternator
By: lynx wind Date: May 31, 2014, 7:14 pm
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This was pretty conservative testing. The coil isn't smashed
down like it will be in the press mold and the gap was about
1/8". So in this test the distance from magnet face to bottom
of coil was about 3/4". On the finished alt this will be closer
to 1/2". I am really pleased with the geometry and the power of
the 3/8" magnets. There is some magic in the thickness and
spacing of magnets on a single plate alt. I learned a lot from
Steve and Bernard back in the day.
Of course there will be surprises along the way, hopefully
mostly good!
#Post#: 3056--------------------------------------------------
Re: Seagull 175 Alternator
By: Otis Date: May 31, 2014, 9:14 pm
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This is exciting!
Hey, I can't find the pdf of a magnet plate, like hgl just
posted a picture of. Is that a scaled jpeg, or something he
whipped up, or did I miss a pdf ?
#Post#: 3057--------------------------------------------------
Re: Seagull 175 Alternator
By: lynx wind Date: May 31, 2014, 9:59 pm
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@Otis,
Its coming along. Just testing stuff right now. There are
compromises to achieve the best performance at the lowest cost.
The magnets are $6.50 each so this isn't cheap. Below is a
layout I have been working from. And a sketch of the
Nessproject's boost circuit we'll try.
#Post#: 3059--------------------------------------------------
Re: Seagull 175 Alternator
By: nessprojects Date: May 31, 2014, 10:46 pm
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@Lynx
Hmmm I think the boost circuit is a little wonky.....The diodes
are shorting the turbine and the caps are doing nothing, slight
drawing fault I think. :)
#Post#: 3062--------------------------------------------------
Re: Seagull 175 Alternator
By: lynx wind Date: June 1, 2014, 7:20 am
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@Nessprojects
Fixed drawing of boost circuit. Thanks for catching. CG, no
idea why you can't download a simple pdf. Might be a Bill Gates
thing.
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