the Otherpower.com Discussion Board || holey stators batmam

Front Page - [Homebrewed Electricity-- (wind) (solar) (hydro) (steam) (controls) (storage) (mechanical)] - Classifieds - Site News
Everything - Newbies - [Remote Living-- (housing) (heat) (light) (water)] - Rants & Opinion - Diaries - Our Products

holey stators batmam
By blueyonder, Section Mechanical Posted on Tue Sep 2nd, 2008 at 12:47:52 PM MST
its not woodworm

another bit done to my gen.
this time i got the coils right. but now what i did with potting.
pics will explain a lot.
first stator i potted got hot. i dident think it was a good thing
to happen to it.
so this time i mixed three lots of resin .
first mix i put glass matt in and resin then put coils on top.
put the lid on mould tight so as to compress everything.
then second mix with more bits matting and resin. again putting lid on tight.
final mix with a good covering of matting and resin again putting lid on mould.
each time leaving it to set and cool down to lose any heat build up.
it never got hot and set very well.
so i never added any powder to help it stay cool.
another thing i did was to put plastic milk bottle tops filled with
plasticine in between each coil.
after the first mix had set.
plasticine gave weight and helped stick to the now dry resin .
then second mix. then final mix.
every thing went well. i done this over a 24 hour of time.
its better for me to take my time and get a good casting rather than do
it in thirty mins and not be happy.
looking at the casting afterwards it turned out good. very happy.
and now to the holey stator.
its not to every ones mind to make air holes in the stator.
but it do sent mean i cant make holes if i want to.
so i did make holes at the casting stage.
it worked out well and i saved resin.
it was my first attempt at doing this holes thing.
i did think about just drilling them. but was scared i might cut or brake a
wire sumwhare.
this way i could see what was happening all the time.
i did lay a lot of glass matting around the outside of holes and coils.
and all the edges for good strength factor.
another thing i did was to use a bit of plastic laminate on the bottom of the
mould . you can see its got a wood like finish but was very smooth.
next one i do i will make the lid from the same stuff.
in the uk its called formica. might be called the same thing in the usa.
just a trade name.
it wasent so bad getting the bits of bottle tops out.
so what do you think about holey stator ? good or bad.?
and now for sum pics

holey stators batmam | 12 comments (12 topical, 0 editorial)

Re: holey stators batmam (3.00 / 0) (#1)
by Flux on Tue Sep 2nd, 2008 at 11:17:50 AM MST
(User Info)

Nice work.
I am not convinced about the holes but apart from a potential source of weakness I can't see them doing any harm. I suspect that by eliminating a filler such as talc or ATH you have lost more thermal transfer than you will gain from the holes but this largely depends on how well you can persuade air to pass through them.

I doubt that any decision could be reached on this without considerable scientific experiment, if holes make you happy then as far as I am concerned they are a good thing.

Flux

Re: holey stators batmam (3.00 / 0) (#2)
by TheCasualTraveler (a.miklos@yahoo.com) on Tue Sep 2nd, 2008 at 07:37:13 PM MST
(User Info) http://thecasualtraveler.com/wind.htm

You crack me up Blue.

No one mixes quality work with homespun ideas quite like you.

Keep it coming.
Andy

Re: holey stators batmam (3.00 / 0) (#3)
by bigkahoonaa on Fri Sep 5th, 2008 at 10:24:51 PM MST
(User Info)

Nice idea Blue.

Have you tried angling smaller holes so that air flows to the stator as your blade spins? It could give you a stronger stator and give you better air flow. Could be a pain manufacturing holes at an angles thru heavy steel plates.

Mau

Re: holey stators batmam (3.00 / 0) (#4)
by blueyonder (windwoodgood at yahoo dot co dot uk) on Sat Sep 6th, 2008 at 03:22:36 PM MST
(User Info)

thanks for the nice comments. fluz andy and mau.
and now i got sum info on the stator.

when winding the coils i was looking for a 220rpm cut in.
testing each coil one at a time ac i was getting 2.5 per coil.
so six coils were 15 ac. so that looked ok to me.
but now with the stator finished and running on test bench.
this is what i am getting out.
rpm volts dc.
260 13.3
270 14.00
300 14.7
320 16.00
330 16.7
340 17.00.
this is with three bridge rectifiers. one per phase.
the dc voltage was lower so i had to close up then good working air gap i had.
now every thing is a bit close .but running free and clear.

it was in my mind i will need open the gap a bit to lower the cut in speed.
or the other thing was to put a bit resistance in the dc line.
now i can see the cut in speed is a bit to high .
but its working well just going a bit fast.
this is with a motor on the bench dring the mill.

but looks like i might lose out a bit in lower winds.
apart from making a new stater and putting sum extra turns on the coils.

two in hand 16awg. 52 turns per coil.(should have put 55)
i suppose that few tuns just makes the difference
so it looks like i am stuck now with the higher winds
and wont get much from the lower ones.

i did connect it to a battery also used a 21 watt light bulb.
i was very impressed with the amps out.
but as it was being pushed with grid power i never took any readings.
would i save anything if i used just two bridge rectifiers.
apart from putting a coat of wax on the blades.
is there anything else i can do to lower the cut in speed.
blade is six foot dia.
i thought i had it right this time. not far out.
its a ill wind that dos no good

Re: holey stators batmam (3.00 / 0) (#8)
by fcfcfc on Sun Sep 14th, 2008 at 07:20:34 AM MST
(User Info)

Hi: I find your test numbers interesting. A while back when I posted "Bill's Super VAWT" goals, I received a whole bunch of _hit from several posters about gen output expectations. Anyway, I find it interesting that between your lowest RPM 240 and the highest RPM 360 you only have a 2% drop in voltage, IE a 30% increase in RPM from 240 yielded a 28% increase in voltage. Thank you for the test coil numbers... very useful...

[ Parent ]

Re: holey stators batmam (3.00 / 0) (#9)
by blueyonder (windwoodgood at yahoo dot co dot uk) on Sun Sep 14th, 2008 at 02:44:07 PM MST
(User Info)

hi bill thanks for the comment .
only thing is i am not very good with maths.
so i am not sure what your saying. is it a good thing or a bad thing.
so far this is the only details i have from testing.
but would like to know what other tests i can do on the bench.
not great with maths or electronics .or in other wards i know zilt.

i would like to try other forms of testing .but without putting it up in the wind.
what can i learn.
as long as i dont need a degree . cheers bill. blueyonder.

its a ill wind that dos no good
[ Parent ]

Re: holey stators batmam (3.00 / 0) (#10)
by fcfcfc on Sun Sep 14th, 2008 at 05:05:18 PM MST
(User Info)

Hi:
No, I think that is good, that is the "tightness" of the NL voltage in relation to RPM... I would be curious about voltage outputs starting from 100 RPM in increments of 50, up to however fast you dare to turn it. Then you would have enough base NL voltage points to put together a nice NL voltage curve. This could be compared to a loaded stator power curve at the same RPM points later on. Those two curves together would be most interesting indeed...

.....Bill

[ Parent ]

Re: holey stators batmam (3.00 / 0) (#11)
by blueyonder (windwoodgood at yahoo dot co dot uk) on Mon Sep 15th, 2008 at 12:41:31 PM MST
(User Info)

sure bill i can log sum data on the bench test.
i did enjoy doing it as it did help me understand things a bit more.
i have been doing other things and every thing is as i left it on the gen.
i never thought to compare this rotor with with another i might make.in the future.

but now with sum fore sight it would be good to copy down sum numbers
and then i can always compare at a later date.
what would be best to test a load on the gen.
i did blow a 21 watt light bulb. but that was mega rpm. evan the ac bench motor
was struggling . so is a battery ok or better with a resister .
one thing i did notice was a sweet and gentile hum as it made power.
that was sweet music to my ears.

i am better off playing with engines at least i can understand how well its
running and starting. but that's off topic .
it might be best if i put results in a diary entry.
cheers again .John.

its a ill wind that dos no good
[ Parent ]

Re: holey stators batmam (3.00 / 0) (#12)
by fcfcfc on Mon Sep 15th, 2008 at 02:35:22 PM MST
(User Info)

Hi:

You blow a light bulb due to over voltage not over current because it is the voltage across the light bulb that determines the current through it (assuming enough is available). So, I would just put two 25 or 40 watt bulbs in series.... I.E. with one wire into one and out, then into the other and out, with the second wire on a switch or something... just not in parallel.. this way you will halve the voltage across each bulb and should be OK...

.....Bill

[ Parent ]

Re: holey stators batmam (3.00 / 0) (#5)
by bigkahoonaa on Sat Sep 6th, 2008 at 09:39:15 PM MST
(User Info)

14.7 V at 300 RPM is not so bad. A few extra turns of wire could have helped. You could try a boost to harvest at lower winds. All depends on your blade.

This is what I was thinking:

I didn't explain myself well. That's what you get when I write late at night. Holes at an angle which could help air flow to stator.

Re: holey stators batmam (3.00 / 0) (#6)
by blueyonder (windwoodgood at yahoo dot co dot uk) on Sun Sep 7th, 2008 at 06:55:14 AM MST
(User Info)

hi mau. you said writing late at night.
then in the morning you read it again and wish you could edit it.
yes i did think about other holes and things but i think i will
have all the airflow i need for the time.
dosent look like this will stall early as cut in is a wee bit to high.
maybe it will be ok.
vanes built into the rotors will also help move air.
so that's as far as i am going with air cooling for now.

its time to move on a bit and start to look at the mast. with my back hurting so
much i am not looking forward to the heavy work.
steel poles are heavy to play with.
i need a sky hook.
its a ill wind that dos no good

Re: holey stators batmam (3.00 / 0) (#7)
by blueyonder (windwoodgood at yahoo dot co dot uk) on Fri Sep 12th, 2008 at 05:24:00 AM MST
(User Info)

from what i was saying about the high cut-in speed.
i was thinking maybe i can cut the prop down a bit.
its a six foot dia. cutting three inches off each blade would make it
turn faster in the same wind-i think?.

i am not sure about this but it seams logical .
but with wind turbines its luck sum times.
its a ill wind that dos no good

holey stators batmam | 12 comments (12 topical, 0 editorial)

Menu

� create account
� How to use the board
� FAQs
� search the board
� Google search the board
� Old Otherpower Board

Login

Make a new account

Username:

Password:

Total Views

��135 Scoop users have viewed this posting.

Related Links

� Also by blueyonder

You must be a registered user to post here. It's easy and free, and the link is on the upper right side of your page.
All trademarks and copyrights on this page are owned by their respective companies. Postings are owned by the poster, but may be deleted or moved at the ADMIN's sole discretion. The Rest � 2003 Forcefield.
You can Email the board ADMIN here. PLEASE include the username you signed up with!