Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

"Bart Bervoets" wrote in message
...
Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

There are some home made wind power generators that work a lot better. Most
motors are built for torque and are supposed to turn a lot faster than a
wind turbine, means what little power you have gets eaten up in a
transmission. Current state of the art has permanent magnets securely
mounted to a disk directly driven by the turbine and the stator windings
mounted stationary to the housing.

"JB" wrote in message
...
"Bart Bervoets" wrote in message
...
Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

There are some home made wind power generators that work a lot better.
Most
motors are built for torque and are supposed to turn a lot faster than a
wind turbine, means what little power you have gets eaten up in a
transmission. Current state of the art has permanent magnets securely
mounted to a disk directly driven by the turbine and the stator windings
mounted stationary to the housing.


But isn't that going to provide AC ? I got the impression from the post
header, that the OP was specifically looking for direct generation of DC. If
I was going to play with this 'on the cheap', I think I would experiment
with a few different automotive alternators from scrappers. Built in reccy.
Built in regulator. As long as you can get it turning fast enough, should be
a reasonably good source of raw DC ?? And if you need AC line power, use it
to charge batteries, and then run an inverter ...

Arfa

On Jul 25, 8:23*pm, "Arfa Daily" wrote:
"JB" wrote in message

...

"Bart Bervoets" wrote in message
...
Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

There are some home made wind power generators that work a lot better.
Most
motors are built for torque and are supposed to turn a lot faster than a
wind turbine, means what little power you have gets eaten up in a
transmission. *Current state of the art has permanent magnets securely
mounted to a disk directly driven by the turbine and the stator windings
mounted stationary to the housing.

But isn't that going to provide AC ? I got the impression from the post
header, that the OP was specifically looking for direct generation of DC. If
I was going to play with this 'on the cheap', I think I would experiment
with a few different automotive alternators from scrappers. Built in reccy.
Built in regulator. As long as you can get it turning fast enough, should be
a reasonably good source of raw DC ?? And if you need AC line power, use it
to charge batteries, and then run an inverter ...

Arfa

IIRC, alternators run faster than car engine speed so that means a
lossy transmission from a slow propeller with a lot of drive torque.
BTW, you'd get AC and then rectify to DC... not quiet clear from your
post where your "AC" and "DC" should be.
Good luck!
Cheers,
Roger

"Engineer" wrote in message
...
On Jul 25, 8:23 pm, "Arfa Daily" wrote:
"JB" wrote in message

...

"Bart Bervoets" wrote in message
...
Does anyone have any large permanent magnet motors that could be used
to
build a few micro wind turbines?

Bart Bervoets

There are some home made wind power generators that work a lot better.
Most
motors are built for torque and are supposed to turn a lot faster than a
wind turbine, means what little power you have gets eaten up in a
transmission. Current state of the art has permanent magnets securely
mounted to a disk directly driven by the turbine and the stator windings
mounted stationary to the housing.

But isn't that going to provide AC ? I got the impression from the post
header, that the OP was specifically looking for direct generation of DC.
If
I was going to play with this 'on the cheap', I think I would experiment
with a few different automotive alternators from scrappers. Built in
reccy.
Built in regulator. As long as you can get it turning fast enough, should
be
a reasonably good source of raw DC ?? And if you need AC line power, use
it
to charge batteries, and then run an inverter ...

Arfa

IIRC, alternators run faster than car engine speed so that means a
lossy transmission from a slow propeller with a lot of drive torque.
BTW, you'd get AC and then rectify to DC... not quiet clear from your
post where your "AC" and "DC" should be.
Good luck!
Cheers,
Roger

The drive pulley on my alternator is about the same size as the one on the
engine, so alternator speed should be roughly equivalent to engine speed. I
don't know whether modern car alternators still use rotating coils and slip
rings, or rotating magnets and static coils, but either way, I wouldn't have
expected there to have been a lot more mechanical losses than in the modern
wind turbine alternators. You don't need to have a car alternator turning
too fast before it reaches regulated voltage output, but I guess if you
wanted to get much actual power from it, you might need to get it going
quite fast, in which case, what you say about gearbox losses will of course,
be true.

I'm not quite sure where you are having trouble understanding what I was
saying about AC and DC. The op's original header said "DC motors for wind
power". If you use a DC motor backwards, or indeed an old car generator - or
dynamo if you like - to produce your wind driven output, then that output
will be DC. No rectification required. That satisfies what he was asking.
If, on the other hand, you use a rotating magnet, fixed stator coil
generator, then this will be an alternator, and will produce AC, which will
require rectifying to get to his originally stated requirement, yes ?

Arfa

"Arfa Daily" wrote in message
...

"Engineer" wrote in message
...
On Jul 25, 8:23 pm, "Arfa Daily" wrote:
"JB" wrote in message

...

"Bart Bervoets" wrote in message
...
Does anyone have any large permanent magnet motors that could be used
to
build a few micro wind turbines?

Bart Bervoets

There are some home made wind power generators that work a lot better.
Most
motors are built for torque and are supposed to turn a lot faster than
a
wind turbine, means what little power you have gets eaten up in a
transmission. Current state of the art has permanent magnets securely
mounted to a disk directly driven by the turbine and the stator
windings
mounted stationary to the housing.

But isn't that going to provide AC ? I got the impression from the post
header, that the OP was specifically looking for direct generation of
DC.
If
I was going to play with this 'on the cheap', I think I would experiment
with a few different automotive alternators from scrappers. Built in
reccy.
Built in regulator. As long as you can get it turning fast enough,
should
be
a reasonably good source of raw DC ?? And if you need AC line power, use
it
to charge batteries, and then run an inverter ...

Arfa

IIRC, alternators run faster than car engine speed so that means a
lossy transmission from a slow propeller with a lot of drive torque.
BTW, you'd get AC and then rectify to DC... not quiet clear from your
post where your "AC" and "DC" should be.
Good luck!
Cheers,
Roger

The drive pulley on my alternator is about the same size as the one on the
engine, so alternator speed should be roughly equivalent to engine speed.
I
don't know whether modern car alternators still use rotating coils and
slip
rings, or rotating magnets and static coils, but either way, I wouldn't
have
expected there to have been a lot more mechanical losses than in the
modern
wind turbine alternators. You don't need to have a car alternator turning
too fast before it reaches regulated voltage output, but I guess if you
wanted to get much actual power from it, you might need to get it going
quite fast, in which case, what you say about gearbox losses will of
course,
be true.

I'm not quite sure where you are having trouble understanding what I was
saying about AC and DC. The op's original header said "DC motors for wind
power". If you use a DC motor backwards, or indeed an old car generator -
or
dynamo if you like - to produce your wind driven output, then that output
will be DC. No rectification required. That satisfies what he was asking.
If, on the other hand, you use a rotating magnet, fixed stator coil
generator, then this will be an alternator, and will produce AC, which
will
require rectifying to get to his originally stated requirement, yes ?

Arfa

My mistake. I was thinking he was looking for some useful output rather
than experimenting with toy motors for a science fair project. Most toy
motors will make some power if you can spin it.

Useful output demands that you design and build your own or buy the
equipment store bought for the purpose. Using automotive components
requires optimizing the turbine some how to provide adequate torque at high
RPM. The idea is to reduce the losses to the minimum AND design optimize
the turbine AND the generator to the available wind. Also bear in mind that
higher voltages reduce ohmic losses in electrical transmission.

One of the more useful designs for automotive generators and alternators,
was the modified 55 gallon drum turbine on wheel bearings with belt drive.

On Sat, 25 Jul 2009 19:30:37 GMT, "JB" wrote:

Current state of the art has permanent magnets securely
mounted to a disk directly driven by the turbine and the stator windings
mounted stationary to the housing.

Yep. Actually a sandwitch of two stator windings with the permanent
magnet in between, also known as a PM "pancake" generator/motor.

"PM Wind Generator Comparison of Different Topologies"
http://people.clarkson.edu/~pillayp/c12.pdf

http://www.hydrogenappliances.com/manta.html (this is a motor but it
can also be used as a generator). Good photos of the construction.

Plenty more found with Google.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sat, 25 Jul 2009 20:33:35 +0200, Bart Bervoets
wrote:

Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

Sure... Everyone has them in stock. All you need to do is supply some
numbers, starting with the average wind speed. That will determine
how much power you can deliver, which will determine the size of the
turbine, which will determine the RPM, which will determine the number
of poles, which will determine the gearing, and which will eventually
determine the specifications of your generator or alternator. When
you're done with that, you might want to check on suitable wide input
range DC to AC inverters. Oh yeah, you might need a tower:
http://www.homepower.com/view/?file=HP105_pg64_Woofenden

Light reading and good references:
http://www.otherpower.com/otherpower_wind.shtml
http://www.homepower.com/basics/wind/
http://www.awea.org
http://www.nrel.gov/wind

You might wanna subscribe to the magazine or get the back issues DVD:
http://www.homepower.com

Ideas:
http://www.aerotecture.com
and not so good ideas:
http://www.buildinggreen.com/auth/article.cfm/2009/4/29/The-Folly-of-Building-Integrated-Wind/



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sat, 25 Jul 2009 20:33:35 +0200, Bart Bervoets
wrote:

Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

If you look on ebay you'll see many used treadmill PMDC motors
sold for this use.

On Sat, 25 Jul 2009 21:48:07 -0400, wrote:

On Sat, 25 Jul 2009 20:33:35 +0200, Bart Bervoets
wrote:

Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

If you look on ebay you'll see many used treadmill PMDC motors
sold for this use.

Choose your treadmill motor wisely:
http://greenterrafirma.com/wordpress/dc-wind-turbine-motors-on-ebay-beware/

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

If you look on ebay you'll see many used treadmill PMDC motors
sold for this use.

Yes, so i now noticed, there are some solutions but alas a bit bulky.
I did some research already and have experimented with car alternators,
i got so far i can make one that charges at 400rpm but the wind is
too unpredictable and the field coil needs to be energized all the time
which drains your battery in dead moments, rather a pm alternator as
suggested as i don't feel much for having to build a dynamo from start,
but hey, if i have to...
But i did buy some motors on ebay as suggested, they are treadmill
motors.
Someone else suggested the use of a motor off an electrical bicycle,
benefit is that it's weatherproof.
I just thought someone here could sell me some instead
of on eekbay.
What i would like is an easy off the shelf solution, but i can see
that there isn't really one.
Thanks everybody for the input on this.

Bart

Bart Bervoets wrote:


If you look on ebay you'll see many used treadmill PMDC motors
sold for this use.

Yes, so i now noticed, there are some solutions but alas a bit bulky.
I did some research already and have experimented with car alternators,
i got so far i can make one that charges at 400rpm but the wind is
too unpredictable and the field coil needs to be energized all the time
which drains your battery in dead moments, rather a pm alternator as
suggested as i don't feel much for having to build a dynamo from start,
but hey, if i have to...
But i did buy some motors on ebay as suggested, they are treadmill
motors.
Someone else suggested the use of a motor off an electrical bicycle,
benefit is that it's weatherproof.
I just thought someone here could sell me some instead
of on eekbay.
What i would like is an easy off the shelf solution, but i can see
that there isn't really one.
Thanks everybody for the input on this.

Bart

Wind turbine kits which include everything except the tower and the wind are
available ... but at a price.

PM alternators avoid the need for field excitation, but now you need some
other way to efficiently regulate output voltage as turbine speed changes.

No need to keep the field energized when the turbine isn't turning. A bit
of control electronics solves that.

A local college just announced an associate degree program in wind power.
I wonder whether the diploma comes with a pair of wooden shoes!

Bryce

"Bart Bervoets" wrote in message
...

If you look on ebay you'll see many used treadmill PMDC motors
sold for this use.

Yes, so i now noticed, there are some solutions but alas a bit bulky.
I did some research already and have experimented with car alternators,
i got so far i can make one that charges at 400rpm but the wind is
too unpredictable and the field coil needs to be energized all the time
which drains your battery in dead moments, rather a pm alternator as
suggested as i don't feel much for having to build a dynamo from start,
but hey, if i have to...
But i did buy some motors on ebay as suggested, they are treadmill
motors.
Someone else suggested the use of a motor off an electrical bicycle,
benefit is that it's weatherproof.
I just thought someone here could sell me some instead
of on eekbay.
What i would like is an easy off the shelf solution, but i can see
that there isn't really one.
Thanks everybody for the input on this.

Bart


You can find them on Sam's Club website 400W for $600

he
http://www.thebackshed.com/Windmill/assemblyMini1.asp
and better i think:

http://hackedgadgets.com/2008/12/05/...ind-generator/
http://www.watchtv.net/~rburmeister/smart.html
http://www.yourgreendream.com/diy_fp_remove_from_wm.php
http://www.ecoinnovation.co.nz/p-349...and-shaft.aspx
http://www.ecoinnovation.co.nz/p-348...and-shaft.aspx

Alain


"Bart Bervoets" a écrit dans le message de news:
...
Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

On Mon, 10 Aug 2009 23:12:36 +0200, "Alain" wrote:

he
http://www.thebackshed.com/Windmill/assemblyMini1.asp
and better i think:

http://hackedgadgets.com/2008/12/05/...ind-generator/
http://www.watchtv.net/~rburmeister/smart.html
http://www.yourgreendream.com/diy_fp_remove_from_wm.php
http://www.ecoinnovation.co.nz/p-349...and-shaft.aspx
http://www.ecoinnovation.co.nz/p-348...and-shaft.aspx

Alain


"Bart Bervoets" a écrit dans le message de news:
...
Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets


Never tried it, but the brushless outrunners used e.g. in model RC
planes might work, specially high KV units (hi torque, low rpm).
Basically these are 3 phase stepping motors, but with some rectifying
it could owrk. And they are getting rather cheap too.

Meat Plow wrote:

On Sat, 25 Jul 2009 20:33:35 +0200, Bart Bervoets
wrote:

Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

Find some old DC generators from autos before they started using an
alternator. Don't know what you would use for a prop maybe some custom
thing out of a polymer like a spinner for a child's toy.

A DC generator generates an AC waveform that is mechanically rectified
by the commutator and brushes. Isn't it better to eliminate the comm
and brushes (maintenance and friction losses) and rectify with diodes?
That's what an alternator does, although its field is rotating while
the DC motor/generator field is stationary.

On 7/26/2009 8:26 AM Bryce spake thus:

Meat Plow wrote:

On Sat, 25 Jul 2009 20:33:35 +0200, Bart Bervoets
wrote:

Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

Find some old DC generators from autos before they started using an
alternator. Don't know what you would use for a prop maybe some custom
thing out of a polymer like a spinner for a child's toy.

A DC generator generates an AC waveform that is mechanically rectified
by the commutator and brushes.

No, an *alternator* does that (which is why it's so called). A generator
just generates plain old DC. Like the ones on old VWs. No diodes.

Dunno how efficient they are compared with alternators, though.


--
Found--the gene that causes belief in genetic determinism

In article ,
David Nebenzahl wrote:
A DC generator generates an AC waveform that is mechanically rectified
by the commutator and brushes.

No, an *alternator* does that (which is why it's so called). A generator
just generates plain old DC. Like the ones on old VWs. No diodes.

The clue is in the commutator. That is a mechanical switch which does
approx. the same as the diodes in an alternator. If the dynamo
intrinsically produced DC it would merely need slip rings as in an
alternator.

--
*What do little birdies see when they get knocked unconscious? *

Dave Plowman London SW
To e-mail, change noise into sound.

On 7/27/2009 11:26 PM Dave Plowman (News) spake thus:

In article ,
David Nebenzahl wrote:

[someone else wrote]

A DC generator generates an AC waveform that is mechanically rectified
by the commutator and brushes.

No, an *alternator* does that (which is why it's so called). A generator
just generates plain old DC. Like the ones on old VWs. No diodes.

The clue is in the commutator. That is a mechanical switch which does
approx. the same as the diodes in an alternator. If the dynamo
intrinsically produced DC it would merely need slip rings as in an
alternator.

What in the world are you talking about? "Mechanical switch"?

The commutator is a set of rotary contacts. My VW (old 6-volt one) had a
generator with a commutator. Produced DC without any diodes.


--
Found--the gene that causes belief in genetic determinism

In article ,
David Nebenzahl wrote:
A DC generator generates an AC waveform that is mechanically rectified
by the commutator and brushes.

No, an *alternator* does that (which is why it's so called). A
generator just generates plain old DC. Like the ones on old VWs. No
diodes.

The clue is in the commutator. That is a mechanical switch which does
approx. the same as the diodes in an alternator. If the dynamo
intrinsically produced DC it would merely need slip rings as in an
alternator.

What in the world are you talking about? "Mechanical switch"?

WTF do you think the purpose of the commutator is? It mechanically
switches the output from each armature winding. If you replaced that with
slip rings so a single armature winding was not switched you'd get AC.
Basic electromagnetic theory.

If you don't believe me have a look at this:-

http://en.wikipedia.org/wiki/Dynamo and click on Contents 1) Description.

The commutator is a set of rotary contacts. My VW (old 6-volt one) had a
generator with a commutator. Produced DC without any diodes.

Then it ran on AC - like many small two strokes etc. They have a rectifier
if they need to also charge a battery.

--
*How about "never"? Is "never" good for you?

Dave Plowman London SW
To e-mail, change noise into sound.

"David Nebenzahl" wrote in message
.com...
On 7/27/2009 11:26 PM Dave Plowman (News) spake thus:

In article ,
David Nebenzahl wrote:

[someone else wrote]

A DC generator generates an AC waveform that is mechanically rectified
by the commutator and brushes.

No, an *alternator* does that (which is why it's so called). A generator
just generates plain old DC. Like the ones on old VWs. No diodes.

The clue is in the commutator. That is a mechanical switch which does
approx. the same as the diodes in an alternator. If the dynamo
intrinsically produced DC it would merely need slip rings as in an
alternator.

What in the world are you talking about? "Mechanical switch"?


You are mistaken in your understanding of a DC generator with a commutator.
Dave is quite correct in that the basic machine generates a bipolar output,
which is made unipolar by the synchronous switching action of the
commutator.

Arfa

David Nebenzahl wrote:

On 7/27/2009 11:26 PM Dave Plowman (News) spake thus:

In article ,
David Nebenzahl wrote:

[someone else wrote]

A DC generator generates an AC waveform that is mechanically rectified
by the commutator and brushes.

No, an *alternator* does that (which is why it's so called). A generator
just generates plain old DC. Like the ones on old VWs. No diodes.

The clue is in the commutator. That is a mechanical switch which does
approx. the same as the diodes in an alternator. If the dynamo
intrinsically produced DC it would merely need slip rings as in an
alternator.

What in the world are you talking about? "Mechanical switch"?

The commutator is a set of rotary contacts. My VW (old 6-volt one) had a
generator with a commutator. Produced DC without any diodes.

Alternators contain a pair of slip rings, one brush contacting each ring
to transfer the generated AC voltage to the output terminals. A generator
has a commutator that is made up of many copper segments separated by
insulating strips. One or more pairs of brushes ride on the commutator.
Armature coils are connected between comm bar pairs. As the generator
rotates, the coils sweep through a stationary magnetic field and
electromagnetic induction creates an AC voltage across the comm bars
which are cleverly arranged so that the positive and negative brushes
cross over the right bars at the right time to convert AC to DC without
diodes.

Old cars used generators 'cuz power diodes were in short supply a
hundred years ago. Automotive alternators became practical around
1960, thanks to silicon power diodes. Alternators are less costly
to manufacture and are more rugged.

Bryce

David Nebenzahl wrote:
On 7/27/2009 11:26 PM Dave Plowman (News) spake thus:

In article ,
David Nebenzahl wrote:

[someone else wrote]

A DC generator generates an AC waveform that is mechanically rectified
by the commutator and brushes.
No, an *alternator* does that (which is why it's so called). A generator
just generates plain old DC. Like the ones on old VWs. No diodes.
The clue is in the commutator. That is a mechanical switch which does
approx. the same as the diodes in an alternator. If the dynamo
intrinsically produced DC it would merely need slip rings as in an
alternator.

What in the world are you talking about? "Mechanical switch"?

The commutator is a set of rotary contacts. My VW (old 6-volt one) had a
generator with a commutator. Produced DC without any diodes.


Wow, A miracle, please show us how!!!
In about fifty years of work in the field, this would be the
first time to see one.

On 7/28/2009 6:27 AM Meat Plow spake thus:

On Tue, 28 Jul 2009 00:20:03 -0700, David Nebenzahl
wrote:

On 7/27/2009 11:26 PM Dave Plowman (News) spake thus:

In article ,
David Nebenzahl wrote:

[someone else wrote]

A DC generator generates an AC waveform that is mechanically rectified
by the commutator and brushes.

No, an *alternator* does that (which is why it's so called). A generator
just generates plain old DC. Like the ones on old VWs. No diodes.

The clue is in the commutator. That is a mechanical switch which does
approx. the same as the diodes in an alternator. If the dynamo
intrinsically produced DC it would merely need slip rings as in an
alternator.

What in the world are you talking about? "Mechanical switch"?

The commutator is a set of rotary contacts. My VW (old 6-volt one) had a
generator with a commutator. Produced DC without any diodes.

The output voltage at the comm is DC not a 'switched by windings and
com bar AC'.

So you agree that a generator (motor used in reverse, i.e., driven
instead of driving, with a commutator instead of slip rings) produces DC
without rectification, not AC, correct? That was my point.

I'm not disputing that the current direction in a generator reverses
with each set of commutator bars contacted by the brushes, so I guess in
that sense one could consider the commutator a "mechanical switch". I
just regard it as the way the thing is wired to produce DC.


--
Found--the gene that causes belief in genetic determinism

Meat Plow wrote:

On Sun, 26 Jul 2009 11:26:13 -0400, Bryce wrote:

Meat Plow wrote:

On Sat, 25 Jul 2009 20:33:35 +0200, Bart Bervoets
wrote:

Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

Find some old DC generators from autos before they started using an
alternator. Don't know what you would use for a prop maybe some custom
thing out of a polymer like a spinner for a child's toy.

A DC generator generates an AC waveform that is mechanically rectified
by the commutator and brushes. Isn't it better to eliminate the comm
and brushes (maintenance and friction losses) and rectify with diodes?
That's what an alternator does, although its field is rotating while
the DC motor/generator field is stationary.

Doesn't an alternator need a voltage on the field to make voltage and
then you regulate the field to regulate the output?

I guess the choice would be up to the OP and his design to store/use
the end product.

An alternator (or, for that matter, a DC generator) need some magnetic
field to sweep windings through. There's usually enough residual
magnetic field in the iron from earlier running to get things started.
The alternator on my standby-power set does this. If the residual
is too small or gone, you gotta "flash" the machine with a brief
current pulse from a storage battery to restore the residual.

Superman would use kryptonite instead.

In article , Meat Plow wrote:
On Mon, 27 Jul 2009 13:41:17 -0400, Bryce wrote:

Meat Plow wrote:

On Sun, 26 Jul 2009 11:26:13 -0400, Bryce wrote:

Meat Plow wrote:

On Sat, 25 Jul 2009 20:33:35 +0200, Bart Bervoets
wrote:

Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

Find some old DC generators from autos before they started using an
alternator. Don't know what you would use for a prop maybe some custom
thing out of a polymer like a spinner for a child's toy.

A DC generator generates an AC waveform that is mechanically rectified
by the commutator and brushes. Isn't it better to eliminate the comm
and brushes (maintenance and friction losses) and rectify with diodes?
That's what an alternator does, although its field is rotating while
the DC motor/generator field is stationary.

Doesn't an alternator need a voltage on the field to make voltage and
then you regulate the field to regulate the output?

I guess the choice would be up to the OP and his design to store/use
the end product.

An alternator (or, for that matter, a DC generator) need some magnetic
field to sweep windings through. There's usually enough residual
magnetic field in the iron from earlier running to get things started.
The alternator on my standby-power set does this. If the residual
is too small or gone, you gotta "flash" the machine with a brief
current pulse from a storage battery to restore the residual.

Superman would use kryptonite instead.

Yeah I have a 4000 watt standby AC generator that rely's on residual
magnetism. There are two types a brushed type (through which you would
flash the field with a 6 volt lantern battery) and a non-brushed type
that I forget at the moment how you get it going when the residual is
gone. But I can almost 99.9% guaranty you that if I remove the field
connection on my Harley that the alternator would produce zero
volktage.

I fooled with a funny little generator my brother gave me. It had little power.
To get it started it had a separate brushed section to get DC. Push a little
button to get it going.

I'm thinking I want to build a wind generator.

Too bad around here, we have miles of rivers, but ZERO water driven
energy. They have new turbins out that you put in rivers and get
some energy. Yeasr ago they did not even think of that. They still
don't.

greg

In article , (GregS) wrote:
In article , Meat Plow
wrote:
On Mon, 27 Jul 2009 13:41:17 -0400, Bryce wrote:

Meat Plow wrote:

On Sun, 26 Jul 2009 11:26:13 -0400, Bryce wrote:

Meat Plow wrote:

On Sat, 25 Jul 2009 20:33:35 +0200, Bart Bervoets
wrote:

Does anyone have any large permanent magnet motors that could be used to
build a few micro wind turbines?

Bart Bervoets

Find some old DC generators from autos before they started using an
alternator. Don't know what you would use for a prop maybe some custom
thing out of a polymer like a spinner for a child's toy.

A DC generator generates an AC waveform that is mechanically rectified
by the commutator and brushes. Isn't it better to eliminate the comm
and brushes (maintenance and friction losses) and rectify with diodes?
That's what an alternator does, although its field is rotating while
the DC motor/generator field is stationary.

Doesn't an alternator need a voltage on the field to make voltage and
then you regulate the field to regulate the output?

I guess the choice would be up to the OP and his design to store/use
the end product.

An alternator (or, for that matter, a DC generator) need some magnetic
field to sweep windings through. There's usually enough residual
magnetic field in the iron from earlier running to get things started.
The alternator on my standby-power set does this. If the residual
is too small or gone, you gotta "flash" the machine with a brief
current pulse from a storage battery to restore the residual.

Superman would use kryptonite instead.

Yeah I have a 4000 watt standby AC generator that rely's on residual
magnetism. There are two types a brushed type (through which you would
flash the field with a 6 volt lantern battery) and a non-brushed type
that I forget at the moment how you get it going when the residual is
gone. But I can almost 99.9% guaranty you that if I remove the field
connection on my Harley that the alternator would produce zero
volktage.

I fooled with a funny little generator my brother gave me. It had little power.
To get it started it had a separate brushed section to get DC. Push a little
button to get it going.

I'm thinking I want to build a wind generator.

Too bad around here, we have miles of rivers, but ZERO water driven
energy. They have new turbins out that you put in rivers and get
some energy. Yeasr ago they did not even think of that. They still
don't.

Now I'm feeling awfull about all the nice big DC motors I,ve thrown away.

greg

Now I'm feeling awfull about all the nice big DC motors I,ve thrown away.

Last year i trashed a big comp tape drive, so i know that feeling.
But one would not get me far anyway, i need quite a few.

Bart

GregS wrote:

snip
Too bad around here, we have miles of rivers, but ZERO water driven
energy. They have new turbins out that you put in rivers and get
some energy. Yeasr ago they did not even think of that. They still
don't.

We had lots of municipal hydro electric generation until sometime in
the 1980s when most were dismantled, ostensibly under pressure from
environmental interests, the state DNR, and utility consolidation.

Michael

On Tue, 28 Jul 2009 15:57:02 GMT, (GregS)
wrote:

Too bad around here, we have miles of rivers, but ZERO water driven
energy. They have new turbins out that you put in rivers and get
some energy. Yeasr ago they did not even think of that. They still
don't.

The problem with rivers is that without a falls, there's no vertical
head to run a high speed turbine or Pelton wheel:
http://en.wikipedia.org/wiki/Pelton_wheel
This is usually solved by building a dam, which has profound
aesthetic, ecological, and environmental issues. It is possible to
use a fully immersed low speed turbine, but to get enough energy from
the usual slow flow rate and high volume river, the number of turbines
and/or their size tend to be large. For example:
http://en.wikipedia.org/wiki/Kaplan_turbine

Also:
http://en.wikipedia.org/wiki/Water_turbine
http://www.homepower.com/basics/hydro/

Another problem is that the power output of the water turbine is
directly proportional to the head and to the flow rate. Unlike the
wind turbine, where the output is proportional to the cube of the air
speed, water power generators tend to become very large at higher
power outputs. Where the flow rate is minimal, the usual solution is
a higher dam.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

In article , Jeff Liebermann wrote:
On Tue, 28 Jul 2009 15:57:02 GMT, (GregS)
wrote:

Too bad around here, we have miles of rivers, but ZERO water driven
energy. They have new turbins out that you put in rivers and get
some energy. Yeasr ago they did not even think of that. They still
don't.

The problem with rivers is that without a falls, there's no vertical
head to run a high speed turbine or Pelton wheel:
http://en.wikipedia.org/wiki/Pelton_wheel
This is usually solved by building a dam, which has profound
aesthetic, ecological, and environmental issues. It is possible to
use a fully immersed low speed turbine, but to get enough energy from
the usual slow flow rate and high volume river, the number of turbines
and/or their size tend to be large. For example:
http://en.wikipedia.org/wiki/Kaplan_turbine

Also:
http://en.wikipedia.org/wiki/Water_turbine
http://www.homepower.com/basics/hydro/

Another problem is that the power output of the water turbine is
directly proportional to the head and to the flow rate. Unlike the
wind turbine, where the output is proportional to the cube of the air
speed, water power generators tend to become very large at higher
power outputs. Where the flow rate is minimal, the usual solution is
a higher dam.

There are problems with everything. Here is what is being done tomorrow.

http://www.hydrogreenenergy.com/technology.html


greg

"Jeff Liebermann" wrote in message
...
On Tue, 28 Jul 2009 15:57:02 GMT, (GregS)
wrote:

Too bad around here, we have miles of rivers, but ZERO water driven
energy. They have new turbins out that you put in rivers and get
some energy. Yeasr ago they did not even think of that. They still
don't.

The problem with rivers is that without a falls, there's no vertical
head to run a high speed turbine or Pelton wheel:
http://en.wikipedia.org/wiki/Pelton_wheel
This is usually solved by building a dam, which has profound
aesthetic, ecological, and environmental issues. It is possible to
use a fully immersed low speed turbine, but to get enough energy from
the usual slow flow rate and high volume river, the number of turbines
and/or their size tend to be large. For example:
http://en.wikipedia.org/wiki/Kaplan_turbine

Also:
http://en.wikipedia.org/wiki/Water_turbine
http://www.homepower.com/basics/hydro/

Another problem is that the power output of the water turbine is
directly proportional to the head and to the flow rate. Unlike the
wind turbine, where the output is proportional to the cube of the air
speed, water power generators tend to become very large at higher
power outputs. Where the flow rate is minimal, the usual solution is
a higher dam.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

I saw a programme on the TV a while back, where a fully submerged vertical
turbine, had been placed in a river here in the UK, that had a substantial
tidal flow. The flow rate of the water first in one direction, and then in
the other as the the tide turned, was remarkably constant, and allowed the
thing to generate failrly significant amounts of electricity, more or less
continuously. I think it was part of an experiment to see if this was
potentially a good way to harness tidal energy.

Arfa

On Sun, 26 Jul 2009 10:17:56 -0400, Meat Plow
wrote:

Find some old DC generators from autos before they started using an
alternator. Don't know what you would use for a prop maybe some custom
thing out of a polymer like a spinner for a child's toy.

Automobile wind generator... Something like this?
http://www.google.com/patents?id=lHkyAAAAEBAJ&printsec=abstract&zoom=4


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Automobile wind generator... Something like this?
http://www.google.com/patents?id=lHkyAAAAEBAJ&printsec=abstract&zoom=4

Sounds like an idea generated by an exuberant moron.

On Mon, 27 Jul 2009 10:29:04 -0400, Meat Plow
wrote:

On Sun, 26 Jul 2009 08:26:40 -0700, Jeff Liebermann
wrote:

On Sun, 26 Jul 2009 10:17:56 -0400, Meat Plow
wrote:

Find some old DC generators from autos before they started using an
alternator. Don't know what you would use for a prop maybe some custom
thing out of a polymer like a spinner for a child's toy.

Automobile wind generator... Something like this?
http://www.google.com/patents?id=lHkyAAAAEBAJ&printsec=abstract&zoom=4

Well yes without the auto and with direct drive. I think the old Delco
generators needed about 900 RPM before the reg snapped on and let
charge voltage to the battery. My brother in law owns a 53 Chevy with
the Blue Flame 6 Vette motor and a DC generator. I've worked on his
voltage reg and it's very inefficient.

I thought you might be amused. When I was in college, I had a 1960
Ford Falcon. It had a generator and mechanical regulator. That
worked tolerably well until I discovered ham radio. The tube type
mobile radios of the day used either dynamotor or vibrator power
supplies, which were a severe drain on the vehicles electrical system:
http://gotcomms.com/motorola_old_twoway/
I vaguely recall something like 6A per radio in receive and 20-60A on
xmit. At my worst, I had 4ea Motorola 80D and 140D radios in the
trunk. The rear springs were bottomed and I could not turn all 4 on
at the same time. To save power, I also installed a "transistor
powered" tube FM radio:
http://gotcomms.com/motorola_old_radios/motorola_fm900_car-radio.jpg
which burned an additional 2A. The generator was just not going to
work. I eventually replaced it with an alternator, which worked much
better.

In college, my Ford Falcon generator was converted into a wind
generator. I have some print photos, but I can't find them. In order
to make it work in light winds, I had to use a fairly large pulley
ratio to get the minimum rpm. I don't recall the numbers, but it
worked in a stiff breeze, and was useless at lower wind speeds.

The reason is that wind turbine output varies with the cube of the
wind speed. That means that at low speeds, tiny changes in wind speed
produce rather large changes in delivered power. The generator also
has a rather non-linear shaft RPM to voltage output curve. If the two
curves have their knee points superimposed by proper pulley ratio
selection, which is the best one can do with such a combination, the
result is miserable performance at low wind speeds, and a rather
abrupt increase in output when the wind goes over the knee. As I
recall, there were only two magnets (two poles) and a commutator in
the automobile generator, while the typical PM wind generator might
have 36 or more. The increased number of poles means that the PM
generator will start producing output at 50 RPM, while the automobile
generator will require about 1000 RPM.

There are also problems at the high end, but I won't go there.

I probably have some old alternative energy books on my shelf that
offer plans for using an old automobile generator, but I couldn't find
anything of the sort with Google. This should offer a clue as to its
popularity. This sorta covers the alternatives:
http://otherpower.com/otherpower_wind_alternators.html
and does not include the automobile generator.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Thanks for the links and as always a great story.

As well thanks from me, i know about otherpower but
i think i come right anyway.

Bart Bervoets