About modifications on a car alternator winding.
Jean Parent
Hello.
I know that a car alternator need arround 1200 rpm to give 14 volts.
But I need to get that 14 volts at lower speed from a car alternator, for
a wind generator.
I have think to add more turn of wire on the stator winding, but those
kind of stators are hard to work.
If I add more turn of wire on the rotor winding , is that gone do same
than if I was add them to the stator ??
It would be much more easy adding wire on the rotor winding.
Any hints ?
Thank
Jean
Steve Work
Jean Parent (bd...@FreeNet.Carleton.CA) wrote:
: Hello.
: I know that a car alternator need arround 1200 rpm to give 14 volts.
: But I need to get that 14 volts at lower speed from a car alternator, for
: a wind generator.
: I have think to add more turn of wire on the stator winding, but those
: kind of stators are hard to work.
A whole lot easier to just use some mechanical means to increase the
alternator speed. Like have the windmill blade turn a 40cm pulley, which
drives the 10cm pulley on the alternator, you use a belt just the same way
it works under the hood of your car. This will make the alternator turn 4
times as fast.
Matthew McDonald
bd...@FreeNet.Carleton.CA (Jean Parent) wrote:
>
>Hello.
>
>I know that a car alternator need arround 1200 rpm to give 14 volts.
>
>But I need to get that 14 volts at lower speed from a car alternator, for
>a wind generator.
>
>I have think to add more turn of wire on the stator winding, but those
>kind of stators are hard to work.
>
>If I add more turn of wire on the rotor winding , is that gone do same
>than if I was add them to the stator ??
>
>It would be much more easy adding wire on the rotor winding.
>
What about using a smaller pulley then the pulley on the wind
generator, wouldn't this make the alternator turn faster thus
achieving the same goal???
regards
matthew
|\ /|
--------------- \ / ---------------
Matthew McDonald \ / Email:
Tasmania Australia \ www.sv.net.au/~matthew / mat...@sv.net.au
+61 41 Matthew / GSM and Piazza Info \ Files etc:
+61 416 288 439 / \ mat...@trump.net.au
_______________ / \ _______________
|/ \|
Stephen Rosenthal
> The Homebuilt Dynamo - Introduction
>
> Why this book?
>
> 1969: Decided to live the simple life. Bought a few acres of steep land
> very cheaply - most of it nearly straight up and down, hard to find a flat
> spot that wasn't marsh or swamp. did find one big enough to erect a 12'x12'
> tent which we lived in for a year while building a small house at the
> bottom end of the property.
>
> 1970: Electric power people wanted lots of money - in advance - to put in
> power poles to house. Seemed like a better idea was to get a book on small
> dynamo construction and make our own power.
>
> To make a long story short, we couldn't find that book. So that's why this
> book was written.
>
> This book is a picture-diary of how we build our dynamo, with some
> practical information and advice along the way for anyone following our
> steps. You will appreciate my wife Julia's invaluable help in translating
> my text into understandable English.
>
> To some people, this book may seem to go into too much detail; for others,
> perhaps not so experienced in electronics or shop techniques, the extra
> details of how I made The Homebuilt Dynamo will be welcomed. My aim is to
> leave out nothing that will help any person with an ordinary home workshop
> to produce a working Homebuilt Dynamo using the materials, tools, and
> techniques described.
>
> Having no such directions ourselves, it took us a while. It was on January
> 15th, 1984, when - with great pomp and ceremony - we retired the smelly and
> dangerous kerosene lamps and started a new era on 12v miniature fluorescent
> lighting fixtures.
>
> The Homebuilt Dynamo is not another "do-it-yourself" book, it is simply a
> careful diary with photographs, detailed working drawings, and text of how
> I build myself a low speed, low voltage, three phase permanent magnet
> alternator with internal rectifier diodes which make, in effect, a direct
> current generator. To avoid that last longwinded description, I have
> substituted the word "dynamo" which, anyway, I hate to see disappear from
> the language.
>
> Except for the small amount of lathe work (see drawings D182 and D183), all
> the construction was done by me, using hand tools normally available in the
> average home workshop plus two handgrinders and two hand powered drill
> presses. To simplify constructions and make it easy to fabricate (and, if
> necessary, to dismantle), I have avoided the necessity for any welding or
> soldering.
>
> Of modular construction, the Stator Units can be removed and the Frame
> completely dismantled using only an Allen key set and a small screw driver.
>
> The materials I used to construct The Homebuilt Dynamo are, by no means,
> the only ones you can use. For example, the Formica Supporting Plates could
> be made from aluminium, cast iron, mild steel, or stainless steel - all of
> which would be heavier and harder to work than the Industrial Formica I
> used, but the output rating of the dynamo could be substantially increased
> because of the much better heat dissipation of metals.
>
> The reader may well ask: why all the fuss over a low speed machine when
> mass-produced car and truck alternators are available at very reasonable
> cost? Well, the answer to that is that the alternative power sources such
> as small windmills, water turbines, and steam engines have speeds in the
> 100 to 800 range of RPM. To match the power source generally available to
> these high-speed machines requires expensive high ratio gearing or a
> complicated maze of belts and pulleys which aren't very energy efficient
> and require frequent maintenance.
>
> In conventional alternators, it is hard to follow the action because a
> common stator core is used for all the windings. In my machine, each
> individual Stator has its own separate laminated core and windings so it is
> easy to make electrical calculations using a modification of the standard
> transformer formula.
>
> The structure of The Homebuilt Dynamo can be thought of as basically a
> bunch of core type electric transformers cut in half and the two halves
> positioned on opposite sides of a rotating disk which has powerful ceramic
> magnets embedded in its rim (which passes between the two halves of the
> "transformers"). The north-south direction of magnetism in each of these
> magnets is opposite to the ones next to it all around the rim, so when the
> disk is rotated, the "transformer halves" on either side of the disk are
> caused to be magnetized first in one direction and then in the other (see
> drawing D296) as each pair of magnets passes between the "transformer
> halves". The "transformer halves" thus act in the same way as the stator of
> an alternator, generating a current of alternating electricity as the
> Magnet Rotor turns.
>
> The amount of power that can be collected from the Stator Units depends on
> three factors which are listed below:
>
> 1. The larger the individual Stator Units, the more power is generated for
> each RPM of the Magnet Rotor.
>
> 2. The more Stator Units that can be packed around the Magnet Rotor disk,
> the more power is generated - that is why I've wound the copper coils in
> such a way that they are much longer than their width in The Homebuilt
> Dynamo, so as to get as many Stator Units as possible around both sides of
> the Magnet Rotor.
>
> 3. The larger the Magnet Rotor, the more magnets can be positioned around
> its rim and this means more power will be generated from each Stator Unit
> for each RPM of the Magnet Rotor.
>
> So, if we want a lot of power at a low rotor RPM, theoretically all we need
> is a huge rotor with hundreds of small magnets revolving between hundreds
> of little stator units. In a real-life situation, though, we have to
> compromise quite a bit here. For example, the rotor unit must be very rigid
> or it will tend to vibrate between the Stator units as it revolves, so its
> thickness must be about one-sixteenth its diameter (for industrial Formica
> material). Also, the Stator Units must be supported by a frame heavy enough
> so that it, as well, will not vibrate.
>
> Obviously, then, compromises must be made and a balance struck between the
> three factors determining maximum power and practical dynamo design.
>
> After experimenting with various combinations, taking each of the three
> factors to its maximum practical limit, my final design brought the frame
> to fourteen and one-quarter inches by fourteen and one-quarter inches by
> one-half inch thick Industrial Formica for the two Supporting Plates with
> four Housing Panels made of fourteen and three-eighths inches by four and
> one-sixteenth inches by one-eighth inch thin aluminium plate. (One of the
> four Housing Panels would become the Rectifier Panel). The eleven and
> five-eighths inches overall diameter Magnet Rotor made of three-quarter
> inch thick Industrial Formica accommodates thirty-two magnets of such a
> size and spacing around its rim that two adjacent magnets will cover two
> legs of the Stator Units, one unit after the other, as the Rotor revolves.
> There are twelve Stator Units fastened to each of the Supporting Plates,
> each exactly opposite one on the other Supporting Plate, making up twelve
> Stator Unit Pairs with the Magnet Rotor revolving between them. The pairs
> of magnets, as they cover the legs of two opposite Stator Units, complete
> the magnetic path between the Stator Unit Pairs as the Magnet Rotor
> revolves (see drawing D296).
>
> The ratio of twelve Stator Unit Pairs to sixteen Magnet pairs is important
> to the three-phase circuitry of The Homebuilt Dynamo since this ration
> works out so that only four pairs of magnets are covering the legs of four
> Stator Unit Pairs (these four Stator Unit Pairs being covered by the four
> pairs of magnets are spaced 90 degrees apart on the Supporting Plates) at
> any one time with the other magnet pairs either just coming up to, or just
> passing on from, the remaining eight Stator Unit Pairs. The effect of this
> is to practically eliminate any "cogging" action which would immobilize the
> Magnet Rotor and make it next to impossible for it to get started again -
> which would be the result if all the magnets lined up with all the Stator
> Units legs at the same time.
>
> On this machine, no extra insulation is used between coil layers and there
> is no process of special dipping, drying, and baking of coils. This is
> because it's not necessary for The Homebuilt Dynamo where the peak voltage
> between any two layers of the coil winding (at maximum rated DC output -
> either parallel or series connected) is just under 2v compared to 54v
> between layers in the coil of a conventional 230v 2kw transformer - where
> insulation and such processes are indeed necessary.
>
> Actually based on an old (turn of the century) idea - which was at the time
> impractical - the design of The Homebuilt Dynamo is only practical because
> of the availability of modern ceramic permanent magnets. When compared to
> the conventional metal magnets, their power is enormous - especially in
> their power to pull over a much greater distance and to withstand strong
> demagnetizing forces. The "long-throw" capability of the modern ceramic
> permanent magnets as used in The Homebuilt Dynamo allows us to have an air
> gap of one-sixteenth inch between the Stator Units and the magnets, on both
> sides of the revolving Magnet Rotor and this means that the construction
> tolerances permitted are much larger than in the conventional machine
> permitting only about a one-hundredth inch air gap - and it is this
> difference which brings the construction of The Homebuilt Dynamo within
> reach of the amateur craftsman.
>
> As an option, in Appendix 1, I have put forward some ideas for enlarging
> The Homebuilt Dynamo by doubling or tripling the linear dimensions of each
> component to gain a really spectacular increase in output and efficiency.
> It is a well-known fact in electrical engineering that electric motors,
> generators, and transformers all become much more efficient as their size
> increase provided that all the components, (with the exception of the
> thickness of the individual iron laminations in the rotor and stator
> cores), are enlarged in the same ratio.
>
> In course of developing The Homebuilt Dynamo, I have often relied on
> hunches about how electricity "could" be generated and consequently I have
> spent quite a few years running up blind alleys, many of which in hindsight
> have seemed a bit ridiculous. I sincerely hope that this book will help a
> like-minded reader to avoid a few of those blind alleys.
>
> What this book contains.
>
> This book originated from the premise that there just had to be a method of
> generating low voltage electricity from mechanical energy which could be
> developed from scratch in the average home workshop using home modified,
> off-the-shelf components and materials.
>
> The systems of construction described here were mainly worked out by the
> Trial & Error System with help from bits and pieces of know-how from
> various trades picked up during 15 years as a factory process worker in the
> Auckland area. I do not profess to be an expert at anything - I'm still
> learning.
>
> This book is a picture-diary with over 300 illustrations detailing (with
> photos, schematics, and working drawings) the design and construction steps
> in the building of a low speed, low voltage, permanent magnet, three-phase
> alternator with built-in full-wave rectifier - which makes it, in effect, a
> DC generator or what I prefer to call a dynamo.
>
> The Homebuilt Dynamo (as wired in this book) can be used from 12v to 36v
> with a top rated output of 1000 watts - 28 amps and 36 volts at 740 RPM.
>
> This machine has been specifically designed and simplified to the point
> where no soldering or welding is required. The use of connector strips
> (terminal blocks) for all wiring connections allows maximum experimentation
> and changing of components without a major hassle. Neither is there any
> foundry work - i.e. no casting for the housing. There are no brushes to
> wear out.
>
> I have done all the work at home (except for an essential bit of lathe work
> done on the Rotor Hub and the four Spacers holding the Main Frame together)
> using all new off-the-shelf quality materials purchased from local firms in
> the Auckland area (these are listed and addresses given).
>
> This book also includes descriptions of how I constructed:
>
> 1. A precision cutting diamond saw used to cut magnets to size (based on
> alterations to a sturdy old hand grinder).
> 2. A special high-power magnetizer used to magnetize ceramic magnets (uses
> old-fashioned telephone dynamo for power source).
> 3. A precision sheet metal cutter (small) for cutting standard transformer
> laminations to the size required (built around a pair of tin snips).
> 4. A small (four and one-half ounces) lifting magnet which uses a Homebuilt
> Dynamo Rotor Magnet as its power source and lifts 145 times its own weight.
> 5. A foot-powered version of The Homebuilt Dynamo (for charging a
> deep-cycle marine battery) build around a bicycle frame with improvised
> reading stand.
> 6. A 139 pound flywheel used on the pedal powered machine made from
> lead-filled mackerel tins set around an Industrial Formica disk with
> aluminium hub and stainless steel rods.
> 7. Precision wire-winding jigs (for winding the stator coils and the
> magnetizing coils).
> 8. Several test apparatus built for various tests on magnets and on the
> Dynamo (in the Appendix).
>
> The appendix also contains details of tests made on The Homebuilt Dynamo
> plus some theories and opinions on various theories and ideas, and some
> simple data on scaling up The Homebuilt Dynamo to obtain large increases in
> output and efficiency.
>
> All the active construction photos in this book show me "doing it the hard
> way" with hand-tools or hand-powered machines - because that was all I had
> to work with. But a person more fortunate, who had the use of power tools,
> would naturally finish the job faster.
>
> Book Review:
>
> The Homebuilt Dynamo by Alfred T. Forbes ... (the rest of the publishers
> details are available on my Home Page)
>
> The background to this book is that the author opted out of the rat race to
> an apparently remote plot of land in New Zealand where he built his own
> house. There was no possibility of getting a connection to a public
> electricity supply but he soon grew tired of the smell and inconvenience of
> oil lamps. He sought a low voltage d.c. generator to charge storage
> batteries which could be driven by a wind or water mill. The obvious
> ready-made article was a car alternator and rectifier but that would have
> needed to run at several thousand r.p.m. and he wanted to avoid the gearing
> or pulley system that would have been needed. He found that if he wanted a
> low-speed machine he would have to build his own. The book records in the
> greatest detail the design and construction of a 3-phase
> alternator-rectifier machine that produces up to 1kW at 740 r.p.m. at
> voltages from 12 to 36 volts depending on the interconnection of the
> windings.
>
> The workshop equipment available to him was of the simplest - he had no
> lathe and of course no power-driven equipment, so the design of the machine
> is dictated largely by this. Consequently its appearance is, for a
> generator, distinctly odd but the electrical engineering in it is
> absolutely sound. It is a multi-pole, permanent magnet rotor machine
> similar in its general philosophy to the original Raleigh bicycle Hubdyno,
> but of course much larger and anyone needing a low-speed generator could do
> much worse than adopt this design.
>
> The author has logged and photographed every stage in the construction and
> has produced in this book the most comprehensive and detailed set of "How
> to do it" instructions I have ever seen. True, the book is expensive but
> the 300 or so pictures are so clear and well-chosen that it must be
> regarded as good value for money. The approach to the subject is
> essentially practical. The theoretical basis of generator design is not
> gone into (it would probably frighten away a number of possible readers)
> but it is clear to your reviewer that the design is soundly based. It could
> be built, following these instructions, by a person with no electrical
> knowledge whatever.
>
> In the education world the construction of this machine would be an
> interesting and instructive project and the completed machine would be
> valuable to illustrate the principles of electromagnetic induction,
> particularly since the form of construction allows the "works" to be seen
> in action. Moreover, the whole machine can be dismantled and reassembled
> without damage, thus adding to its instructional value.
>
> In short, the book presents a rather specialised project but it does it in
> an easily assimilated way. It just goes to show what you can do with your
> bare hands if you set your mind to it. H.D.B.
>
> (MODEL ENGINEER 15 DECEMBER 1989 VOL 163 #3863, page 793)
>
> The Homebuilt Dynamo
>
> To order contact:
>
> Todd-Forbes Publishing
> P.O. Box 3919
> Auckland
> New Zealand
>
> Ph +64-9-818-8967
> Fax +64-9-818-8890
>
> $72(US) postpaid - by Check, Bank Draft or American Express
>
> If paying by Amex please post or fax your card no., expiry date and name as
> it appears on your card. Your Amex statement will show a $NZ amount
> converted into your local currency.
>
>
> ___________________________________________________
>
> GLOBAL OPPORTUNITY DYNAMICS FOR THE 21ST CENTURY
>
> Email my autoresponder glo...@suzton.com for Report
> "The 3 Hottest Global Opportunities on the Planet"
>
> http://www.entrepreneurs.net/members/power.htm
>
> Ian Fraser ifr...@ihug.co.nz
> Sovereign Individual & World Citizen
>
> WHAT YOU THINK TODAY, YOU WILL BECOME TOMORROW!
> ___________________________________________________
>
>
Stephen Rosenthal
Jean Parent
Matthew McDonald (mat...@sv.net.au) writes:
> bd...@FreeNet.Carleton.CA (Jean Parent) wrote:
>
>>
>>Hello.
>>
>>I know that a car alternator need arround 1200 rpm to give 14 volts.
>>
>>But I need to get that 14 volts at lower speed from a car alternator, for
>>a wind generator.
>>
>>I have think to add more turn of wire on the stator winding, but those
>>kind of stators are hard to work.
>>
>>If I add more turn of wire on the rotor winding , is that gone do same
>>than if I was add them to the stator ??
>>
>>It would be much more easy adding wire on the rotor winding.
>>
> What about using a smaller pulley then the pulley on the wind
> generator, wouldn't this make the alternator turn faster thus
> achieving the same goal???
I allready did that, but not very efficient etc.. and it give mecanical
problems with the times, etc...
Low RPM are better in my view.
Thank
Bye
Jean
Jean Parent
Stephen Rosenthal (top...@primenet.com) writes:
>> The Homebuilt Dynamo - Introduction
>>
>> Why this book?
>>
>> 1969: Decided to live the simple life. Bought a few acres of steep land
>> very cheaply - most of it nearly straight up and down, hard to find a flat
>> spot that wasn't marsh or swamp. did find one big enough to erect a 12'x12'
........
>>
>> All the active construction photos in this book show me "doing it the hard
>> way" with hand-tools or hand-powered machines - because that was all I had
>> to work with. But a person more fortunate, who had the use of power tools,
>> would naturally finish the job faster.
Hi
I did read that books at the public librairy, but can't find thoise
magnets, can't have th laminations ... Well...
So I will stick to my alternator modifications :-)
Thank
Jean
John Freitag
> But I need to get that 14 volts at lower speed from a car alternator, for
> a wind generator.
>
> I have think to add more turn of wire on the stator winding, but those
> kind of stators are hard to work.
...
> It would be much more easy adding wire on the rotor winding.
I think that your easist fix is to gear up the drive to spin the
alternator faster.
Secondly, use a variable speed motor and experiment with different
excitation voltages. Raising the excitation current will accomplish the
same thing as adding more turns as Speed * turns * Field amperes is the
basic equation you are working with. You will probably have to disable
the voltage regulator if it is internal and go direct to the rotor slip
rings with the excitation. You can overdo it and burn out the rotor too,
so you have to be careful.
Rewinding either the rotor or the stator would be an awful hassle it you
don't have the proper machinery. Remember it has to be balanced at a
relatively high speed and the windings cannot fly apart from centrifigal
force. Also the stator is typically 3 phase sou you would have to do all 3
equally.
John Freitag
--
THE REPLY, OF COURSE, DOES NOT REPRESENT ANY OFFICIAL POSITION OF THE UNIVERSITY, only my personal opinion.
altavoz
Stephen Rosenthal wrote:
>
> > The Homebuilt Dynamo - Introduction
> >
> > Why this book?
> >
"16 magnet pairs to 12 stator.....least cogging.
with 16 magnets and 15 stator pairs you get the least cogging
and you put diodes on each stator.
He also says belts are no good . The serpentine auto belt
is much more effecient than a "V" belt . He may have missed
that.
This is good for some places but the flat belt driven alt works
very well and may be a better solution in some places.
______End of text from alt...@azstarnet.com___________
altavoz
Jean Parent wrote:
> Hello.
> I know that a car alternator need arround 1200 rpm to give 14 volts.
> a wind generator.
> I have think to add more turn of wire on the stator winding, but those
> kind of stators are hard to work.
> than if I was add them to the stator ??
You cant rewind the rotor. There's no need to anyway. It's easy to
rewind the stator with 18 ? gage and triple or better the turns .
This will kick the volt up at lower RPM. It's a close race to use
a flat auto belt and an idler. They allow a very high ratio
( up to 50:1)
The old alts needed .1 amp from a batt' , today they either "flash"
the rotor like an old DC generator or they embed a small magnet in the
rotor .
______End of text from alt...@azstarnet.com___________
end of text end of text end of text end of text end of text
John Lundgren
Jean Parent (bd...@FreeNet.Carleton.CA) wrote:
: Hello.
: I know that a car alternator need arround 1200 rpm to give 14 volts.
: But I need to get that 14 volts at lower speed from a car alternator, for
: a wind generator.
: I have think to add more turn of wire on the stator winding, but those
: kind of stators are hard to work.
: If I add more turn of wire on the rotor winding , is that gone do same
: than if I was add them to the stator ??
: It would be much more easy adding wire on the rotor winding.
: Any hints ?
If anything, the additional wire on the rotor will make the rotor require
more voltage to give the same magnetic field, and I presume the same
output. Really what you want to do is gear the alternator to the wind
generator with something that gives a higher RPM. THis could be pulleys
and a belt, or a real set of gears. The normal engine RPM is much less
than the RPMs of the alternator, and the high RPMs are necessary to get
the output.
: Thank
: Jean
--
#===================================================================#
| John Lundgren - Elec Tech - Info Tech Svcs. | jlundgre@ |
| Rancho Santiago Community College District | deltanet.com |
| 17th St at Bristol \ Santa Ana, CA 92706 | http://www.rancho|
| My opinions are my own, and not my employer's. | .cc.ca.us |
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#======P=G=P==k=e=y==a=v=a=i=l=a=b=l=e==u=p=o=n==r=e=q=u=e=s=t======#
Rick Jones
Steve Work wrote:
>
> Bob Selfinger (self...@ee.net) wrote:
>
> : What would happen if you used two alternators and then put the outputs
> : from the two in series with each other? I can't think right now
> : exactly what will happen. It works with two DC flashlight batteries.
> : You get double voltage that way. Maybe if you have to, you can
> : rectify and filter first before the series coupling. I am not an
> : expert on this. I am just fishing around for an answer.
Regulator will limit it to 12V, besides, you cant series them because
they are both negative ground, you would need an insulated ground to
accomplish this.
If its 24V you want, get 2 12V batterys and hook up a series/parallel
switch in the system, big trucks do this for cold weather areas to get
12V, but have 24V start. Or get a 24V alternator (easy to convert a
Delco SI series to do this) have it charging 2 12V batteries wired in
series, than run your 12V acc from either battery for 12V and have 24V
on tap too.
Ever see a Delco alternator put out 150 volts AC? I built one, but
amperage was limited to lighting only, no power tools.
I did build a delco generator to do 110VAC, and this will run power
tools (true AC, unlike a converter).
email to find out how.
Rick, Toyota Master/ASE Master/L-1
Bob Selfinger
>> bd...@FreeNet.Carleton.CA (Jean Parent) wrote:
>>
>>>
>>>Hello.
>>>
>>>I know that a car alternator need arround 1200 rpm to give 14 volts.
>>>
>>>But I need to get that 14 volts at lower speed from a car alternator, for
>>>a wind generator.
>>>
What would happen if you used two alternators and then put the outputs
from the two in series with each other? I can't think right now
exactly what will happen. It works with two DC flashlight batteries.
You get double voltage that way. Maybe if you have to, you can
rectify and filter first before the series coupling. I am not an
expert on this. I am just fishing around for an answer.
Maybe a second alternator will just double the load on the wind
generator and cut the rpm in half! I don't know if you will be any
better off if this happens.
Good luck!
<snip>
Steve Work
Bob Selfinger (self...@ee.net) wrote:
: What would happen if you used two alternators and then put the outputs
: from the two in series with each other? I can't think right now
: exactly what will happen. It works with two DC flashlight batteries.
: You get double voltage that way. Maybe if you have to, you can
: rectify and filter first before the series coupling. I am not an
: expert on this. I am just fishing around for an answer.
Ain't gonna work because most alternators have a built in regulator which
tries to keep the voltage at 12-14 volts regardless of RPM. Unless you want
24V, which you might, this really won't help.
Like I said, I think the best thing is just to use automotive belts and
pullies to speed up the RPM. If the windmill is unable to run this
arrangement, it won't be able to provide the same amount of power with
any other arrangement, such as a re-wound alternator.
altavoz
Rick Jones wrote:
> Regulator will limit it to 12V, besides, you cant series them because
> they are both negative ground, you would need an insulated ground to
> accomplish this.
And another thing you need 12vdc for the rotor, you'll get 6vdc from
the stator ..not enuff. Breaking ground is easy, so both leads will
be isolated.
> If its 24V you want, get 2 12V batterys and hook up a series/parallel
> switch in the system, big trucks do this for cold weather areas to get
> 12V, but have 24V start.
> Or get a 24V alternator (easy to convert a Delco SI series to do this) No need to convert alt , it will put out over 100vdc at high RPM. on
internal reg , all you do is hook the sense wire to 12 volts and the
output will go to 100 + ! So just hook a voltage divider to sense wire.
a 700 ohm to gnd and a 4300 ohm to stator will reg it to 100 vdc.
have it charging 2 12V batteries wired in
> series, than run your 12V acc from either battery for 12V and have 24V
> on tap too.
> Ever see a Delco alternator put out 150 volts AC? I built one, but
> amperage was limited to lighting only, no power tools.
> I did build a delco generator to do 110VAC, and this will run power
> tools (true AC, unlike a converter).Dont you mean 110VDC ? the ac is 3 phase !
> Rick, Toyota Master/ASE Master/L-1
You need very high RPM 4000,5000 to get high volt ( DC) from any
standard alternator. The problem is where do you get 12vdc for the
rotor ? The battery ! The alt will kick out a lot of watts !
They're getting smarter now they're winding delta .
F.P.Harrison
> But I need to get that 14 volts at lower speed from a car alternator, for
> a wind generator.
>
The main advantage that I can see to using car alternators in this
application is that they are cheap and easy to get. Unfortunately, they
are also relatively ineffecient, because in the service for which they
are intended, ruggedness, reliability, and ease of manufacture are
more important than electrical effeciency. Don't expect to get more
than 30% of the mechanical energy back out in the form of electricity.
One obvious flaw in the typical car alternator is the stator to rotor
mechanical clearances. A big gap means sloppy bearings, and stamped as
opposed to machined, parts. It's hell on efficiency, but hey, it's
cheap.
A better approach might be to check out the surplus market (Surplus Sales,
Northern Hydraulics, etc.) for a deal on a 1 HP 12VDC low RPM motor, permanent
magnet type if you can find one, and use it for a generator. Often these
places have beautifully made stuff for 10-20%, of what you would pay
for a new one from a manufacturer or distributor. Sometimes it's junk too,
so be careful. A high quality motor/generator can give as much as 90%
efficiency, which means three times the electricity from the same
tower/rotor combination as opposed to a car alternator, plus you don't
have the frustration of trying to get an alternator to do something is
was never really designed for. Not that you CAN'T, oviously people have
gotten that approach to work, but there are easier ways to go.
Frank Harrison
Duane C. Johnson
Hi F.P.;
F.P.Harrison wrote:
> A better approach might be to check out the surplus market (Surplus Sales,
> Northern Hydraulics, etc.) for a deal on a 1 HP 12VDC low RPM motor, permanent
> magnet type if you can find one, and use it for a generator. Often these
> places have beautifully made stuff for 10-20%, of what you would pay
> for a new one from a manufacturer or distributor. Sometimes it's junk too,
> so be careful. A high quality motor/generator can give as much as 90%
> efficiency, which means three times the electricity from the same
> tower/rotor combination as opposed to a car alternator, plus you don't
> have the frustration of trying to get an alternator to do something is
> was never really designed for. Not that you CAN'T, oviously people have
> gotten that approach to work, but there are easier ways to go.
>
> Frank Harrison
I think this is a good sugestion too. I just want to add a
detail about the use of DC motors as generators.
When the DC motor is used as a motor the brushes are advanced
with respect to the stator. This compensates for the current
buildup lag in the rotor.
When you use the DC motor as a generator the brushes need to
run retarded. The easiest way to do this is to turn the
generator in the oposite way the motor was run.
Some DC motors are constructed simetrically. These motors are
designed to run in either direction. These motors have no
brush advance. These motors don't have the optimum advance
needed for maximum efficiency. Sometimes the endplates can be
rotated to change the advance or retard.
Good Luck.
--
CUL8ER
Stupid is Forever
Ignorance can be Fixed
Duane C. Johnson
Ziggy
WA0VBE
Red Rock Energy
1825 Florence St.
White Bear Lake, MN, USA 55110-3364
(612)635-5065 w
(612)426-4766 h
red...@pclink.com
dc...@PO8.RV.unisys.com
http://www.geocities.com/SiliconValley/3027/
Rick Jones
Your missing the point!
He's referring to "genuine AC" which can "never" come from a battery but
maybe a DC generator with expensive electronic polarity switching
device.
You see, any induction motor (thats ones without brushes) will never
work on DC, they just set there amd hum (don't recognize the tune)
Those 110V converters are DC and will run electric motors like a drill
or any with brushes.
I know that Ford does make a 120VAC alternator for electrically heated
glass (unsure which one, but must be for cold climates) as I have never
seen one.
Any Ford Techs with a P/N?
Rick, Toyota Master/ASE Master/L-1/KC7AXU
Andy Dingley
The moving finger of altavoz <alt...@azstarnet.com> having written:
>This is good for some places but the flat belt driven alt works
>very well and may be a better solution in some places.
Minor note - these serpentine automotive belts aren't flat, they're
polyvee
Old leather or fabric flat belts on crowned pulleys just aren't the
same. They're quite efficient (belts aren't as stiff as a V, so
there's less loss as heat that way), but their power transmission
capabilities are limited.
--
Do whales have krillfiles ?
Mark Kinsler
Jean Parent <bd...@FreeNet.Carleton.CA> wrote:
>I know that a car alternator need arround 1200 rpm to give 14 volts.
>a wind generator.
If you're using a Delcotron alternator, you'll have to disable the
internal regulator, which you can do by shorting a special terminal on
the regulator assembly to ground. This is routinely done to test the
regulator (they use a screwdriver to short the terminal) and will kick
the output voltage up to something like 30 volts at normal engine
speeds. Whether this will help with your wind generator depends upon
the rotor speed. If you use a generator that doesn't have an internal
regulator, just connect a battery in series with a variable resistor
across the rotor brushes. Adjust the variable resistance so that you get
the voltage you want. If you're charging batteries with the alternator
you'll need to design a voltage regulator so that the batteries don't
overcharge.
Mark Kinsler
Duane C. Johnson
I refering F.P.Harrison's post about 12VDC 1HP motors which are using
brushes and comutators. DC motors without brushes can not be used as
generators becouse there solis state switches are one way devices.
Ie. in not out.
> You see, any induction motor (thats ones without brushes) will never
> work on DC, they just set there amd hum (don't recognize the tune)
That was why F.P. was talking about DC motors with brushes.
> Those 110V converters are DC and will run electric motors like a drill
> or any with brushes.
We were saying that the windmill guy should use low rpm DC motors as
generators becouse cheap automotive alternators are to inefficient
, one poster thought 30%, and need to high of an rpm to be useful for
the windmill.
> I know that Ford does make a 120VAC alternator for electrically heated
> glass (unsure which one, but must be for cold climates) as I have never
> seen one.
> Any Ford Techs with a P/N?
>
> Rick, Toyota Master/ASE Master/L-1/KC7AXU
This whole thread on how to rewind alternators is based on how to get
sufficient voltage at low rpms. Windmills inherently deliver low rpms
and we were just trying to give an alternative to the use of alternators.
DC motors used as generators has shown to be a good and efficient solution
in the past.
BTW the old automobile generators suffer similar low efficiencies as do
automobile alternators do. Again probably due to cheap constructio and
the fact that the engine thay are attached to has ample power to run them.
Boris Hüttmann
Jean Parent <bd...@FreeNet.Carleton.CA> schrieb im Beitrag
<4vjqaa$a...@freenet-news.carleton.ca>...
>
> Hello Jean,.
I know the problem. For a hydro-power I used an alternator at 3000 rpm but
I used a permanent magnet from an loudspeeker for Rotor feeld. The effekt
was the voltage only coms up to 6 V. First Tests with mor windings were not
sucsessfull. Sekond try I used three transformer for the three phases. By
useing the 12 V winding of every transformer vor output and adding new
windings with heavy copper for the input.
But for the high frequenzy it woud be better to bild a spezial adapted
transformer.
To increes the number of rotor-windings is not much effectiv becaus the
magnetic flux is neerly saturated. and the losses increes.
The best way is to rewind the stator!
greeting from Johann j.wim...@t-online.de
Matthew Scott
huet...@t-online.de (=?ISO-8859-1?Q?Boris_H=FCttmann?=) writes:
>Jean Parent <bd...@FreeNet.Carleton.CA> schrieb im Beitrag
><4vjqaa$a...@freenet-news.carleton.ca>...
>>
>> Hello Jean,.
>I know the problem. For a hydro-power I used an alternator at 3000 rpm but
>I used a permanent magnet from an loudspeeker for Rotor feeld.
how can you fit a loudspeaker magnet inside an automobile alternator?
It seems to me that they don't just have the wrong shape, but also
absolutely the wrong poling. I took some curved magnets out of a dc motor,
glued them into the rotor of a larger motor with epoxy saturated with soft
iron filings. The magnets were the right shape, and they were poled
correctly. Coupling the rotor with a spring to a small test wind mill
brought about 8 volts ac at about 200 rpm. Coupling the rotor directly
reduced the voltage to about 6 volts ac. (the spring coupling allowed
the natural magnetic drag of the generator to produce jolts of
movement resulting in higher voltage) My generator was not a third so
large as an automobile alternator, and my magnets were small. I used 2 of
them at about 2 square inches area a piece. I would guess with the
same methodic, larger magnets, ect. An Automobile alternator could
make at least 8 or 9 volts ac with much lower internal resistance. I have
one or two dc motors here at home with about the right size of magnets.
> The effekt
>was the voltage only coms up to 6 V. First Tests with mor windings were not
>sucsessfull. Sekond try I used three transformer for the three phases. By
>useing the 12 V winding of every transformer vor output and adding new
>windings with heavy copper for the input.
>But for the high frequenzy it woud be better to bild a spezial adapted
>transformer.
are you sure? 3000 rpm with two poles sounds like about 50 hz. That's
about what transformers are designed for. Is this the same auto alternator
at 3000 r.p.m? My little tiny generator here (much smaller than auto alternator)
would create about 20 to 30 volts d.c. with an internal resistance of about .7 ohms
under the same circumstances (without transforming the output up)
>To increes the number of rotor-windings is not much effectiv becaus the
>magnetic flux is neerly saturated. and the losses increes.
I don't see how rewinding the rotor could be successful anyway. If you
want more magnetic field there, you'll have to drive more power into
it one way or the other. That means danger of burning out, more power loss,
increased voltage requirements and danger of saturating. Pulsing the rotor
could increase efficiency as long as it doesn't get too saturated.
>The best way is to rewind the stator!
Considering the comments and comparisons I have made, I really wonder if
you have properly installed magnets into your alternator. There is a large
number of possible mistakes in the installation, maybe you would like to
discuss exactly what you did as it appears that my small generator is
outperforming your large one.
Duane C. Johnson
Matthew Scott wrote:
>
> huet...@t-online.de (=?ISO-8859-1?Q?Boris_H=FCttmann?=) writes:
>
> >Jean Parent <bd...@FreeNet.Carleton.CA> schrieb im Beitrag
> ><4vjqaa$a...@freenet-news.carleton.ca>...
> >>
> >> Hello Jean,.
> >I know the problem. For a hydro-power I used an alternator at 3000 rpm but
> >I used a permanent magnet from an loudspeeker for Rotor feeld.
>
> how can you fit a loudspeaker magnet inside an automobile alternator?
Have you looked inside an automobile alternator? The one I have in my hand
has a set of 12 poles, 6 N and 6 S. I think some alternators have more
poles. These poles are energised magnetically from a single electromagnetic
in the center with wire wound circumfrentially around the core. This makes
the north on one end of the shaft and the south on the other end.
If the north end has a disk and the south end has a disk there would be
only 2 poles. Now cut 6 notches in each disk and bend them toward each
other. This forms 12 poles around the periphery. So on each rotation it
makes 6 cycles.
Now a speaker magnet is a flat disk with a hole in the center. The top
and the bottom of the disk are the poles. If this is placed on the shaft
of the rotor then there will be a small magnetism on the main poles.
Wire is still wound to increase the field. The magnets are used to output
some power with no excitaton kind of like a trickel charge.
> are you sure? 3000 rpm with two poles sounds like about 50 hz. That's
> about what transformers are designed for.
Well I think it is more like 6 times 50Hz = 300Hz. Becouse there
are 12 poles not 2 poles.
Matthew Scott
"Duane C. Johnson" <red...@pclink.com> writes:
> Hi Matthew;
>
> > >
> > > If the north end has a disk and the south end has a disk there would be
> > > only 2 poles. Now cut 6 notches in each disk and bend them tward each
> > > other. This forms 12 poles around the periferal. So each rotation makes
> > > 6 cycles.
> > >
> > > Now a speaker magnet is a flat disk with a hole in the center. The top
> > > and the bottom of the disk are the poles. If this is placed on the shaft
> > > of the rotor then there will be a small magnetism on the main poles.
> >
> > sounds like a very inefficient use of the magnet. No wonder it doesn't
> > create very significant voltage.
>
> That was the purpose. I have seen comercial Japanese car alternators with the
> magnet installed just as I described. The purpose is to generate a "trickel"
> charge even with no current in the field windings. The trickel current is enough
> to get the field started when more power is needed. This magnet is quite small.
>
> > It seems to me that a large portion
> > of the flux that manages to get to the shaft will be immediately conducted
> > straight through the shaft to the other pole of the magnet without bothering
> > the output coils at all.
>
> It dosn't make any difference that the "minor" magnetic field is somewhat shunted
> as it is ment for trickel current purposes.
This is only logical if you care about 2 watts at 1 volt. I can see how it
could be useful to make the alternator independant of the car battery. Transforming
the power up to 12 volts would mean losing 1 3/4 out of the two watts, so I don't
see the value of it as a power generating device, except to prime the coils when
high speeds come. >
> > Using a magnet with a much larger hole than the shaft could
> > minimize this effect, but it probably wouldn't fit well. Furthermore, I can't
> > hardly imagine a way to implement a complete flux circuit from one pole of
> > the magnet to the other without shorting it through the shaft.
> > This is no problem with auto alternators as the shaft is wound with wire. This
> coil of wire is what is used to produce the "main" magnetic field.
right, this is obvious, but I don't want to fiddle with the wire (worry when
there should be current, when not, how much ect.) or worry about
replacing the brushes, or losing energy in their friction. I don't intend
to use the thing with an automobile.
>
> > It seems
> > to me that the rotor coil should also produce a small voltage. Was it useable?
> > Personally, I wouldn't bother with this kind of setup. You must have either
> > had a use for such tiny amounts of power, or not have originally seen the
> > weakness of the configuration.
>
> Of course! The magnet was for trickel currents with no input from the regulator.
> I you want more output the electromagnetic generally can make a larger field
> than passive permanent magnets.
this is believable.
>
> For this thread we were discussing the generators connected to wind turbines.
> These turbines have a wide operating power range. They must run at mostly at
> low wind speeds an intermitantly at high wind speeds. Since the power
> generated is the square
2
oops! the cube! 1/2 mv * v (more air with squared more energy)
>of the wind speed there is a large difference between
> maximum and minium power levels.
obvious
>
> All things being equil permanant magnet rotors have more starting torque
> than do electromagnetic rorors.
likely, but not an awful lot since electromagnetic rotorsrequire
also carbon brushes with friction. Friction is a real
loss, magnetic drag an imaginary one, so that once the thing
is started, it can go faster than if it had frictional loss.
>This is becouse the field is larger than
> needed for low power operation.
do you mean low power or low speed?
you seem to be assuming transforming the tiny voltage up with large efficient
transformers to make it useful. I don't intend to waste the time or the
transformers for a few watts.
> Of cource the poles can be balanced to minimize
> the the starting but the same can be done for the electromagnetic rotor also.
obvious
>
> All things being equil the electromagnetic rotors have higher field strengths.
believable.
> This is becouse if more field strength is needed more current can be applied.
> The limit to the field density is when the pole pieces have been magnetically
> saturated.
or when the coil burns out, or when you don't have easy access to the voltage
needed to drive lots of current through it.
> Permanent magnetics can't produce a field strong enough to saturate
> the poles. Of course the permanent magnet dosn't consume any power.
which is a nice advange when the machine is hardly putting anything out.
>Of course
> the electromagnetic rotor only needs this higher field when in high winds where
> ample power is available.
unless you realize that 1 volt is useless because it doesn't charge a thing unless
it goes through lossy transformers. Just rectifying it loses half its power. This
means that at low speeds, getting useful output voltage requires large input
currents...likely more input than output.. Pulsing the rotor is definitely
adviseable in this case.
>
> > I was considering putting magnets in automobile alternators. After your
> > description, I probably won't bother wasting my time.
>
> One method for installing the magnets is to remove one rotor pole piece and
> cut a large hole in it, as you said. Then epoxie many flat magnets to the still
> attached rotor pole disk. Now epoxie the modified pole disk to the now glued
> magnetics. This is how some comercial low speed alternators are made.
This might work if you have precision equipment. I doubt the thing would
turn right after I tried this with my home workshop. It seems to me that the
shaft would still do a lot of flux grounding unless a portion of it were removed,
making the need for precision prebably greater. I'm sure this is possible, but
I'm not excited about it. I'm sure it's much more difficult than grinding out
magnet sized chunks of steel.
>
> > AC motors are much better for this purpose and there are lots
> > of them in old washers, dryers, refridgereators, vaccuum cleaners and wherever
> > else you want to look. With the proper magnets, they'll probably behave as
> > well as the auto alternator with current. I have a pair of curved magnets
> > out of a dc motor about two or three times larger than those I used in my
> > prior experiment. In the right motor, I expect at least 4 times the voltage
> > output of the other motor I used.
> > I think that if you want to use the flat magnetics the double disk type of rotor
> in car alternators is easier to modify.
no doubt about this. I wouldn't touch an ac motor with a flat magnet. This is
a fools quest. Curved magnets aren't so hard to come by though. You can find
them in any dc motor, and just look for an ac motor with the right size of
rotor.
> The auto alternator also usually have
> 12 poles per rotation. Most of the AC motors have 2 or 4 poles per rotation.
> With more poles you get an alternator that works beter al lower rpm.
I'd be happy about 12 poles if I thought I could get it to work.
>
> > It takes a while to grind out a place to
> > glue the magnets in. I used a 400 watt drill with a grinding wheel, and it
> > took about 4 hours. With a 1 hp. grinder, I expect a larger one to take
> > about the same amount of time. It should be superior to a car alternator
> > when finished though. A little magnetic drag to try and reduce, but no more
> > brushes. My little generator out of a vaccuum cleaner motor takes about
> > 3 to 4 seconds to stop after I spin it with my fingers.
>
> This is showing that the bering is low in friction.
right, and that there is happily no brush friction loss. Most of the
friction in the motors I have played with was from the brushes. This
friction can be as large as the magnetic drag of an alternator with
magnets, only the energy gets lost instead of just stored in magnetic
fields where it comes back out. Brushes are at least as much of a problem
at low wind speeds as magnetic drag.
> The car alternator will do this also.
if it does, it's only because it stores more kinetic energy in its
much larger rotating shaft. Now turn on the coil and discover that
the hysteresis losses also slow down the shaft. My little motor
spun a lot longer without the magnets even though the magnets stored
extra kinetic energy.
>The main friction is in
> the brushes for the rotor windings but this is a small loss.
at high speeds since frictional loss is only proportional to the
angular velocity where output power is proportional to the square
of the angular velocity. At low wind speed, the brushes are a problem,
particularly when gearing is used since gearing multiplies the forces.