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'Air powered electronics'
2000\04\13@175251 by Morgan Olsson

picon face
I«m working on a project where the customer don«t want electric connection.
And no batteries needing to charge, switch or anything like that either.
Too dark/small/dusty to use solar power.

It«s a kind of moving hose connected pressure air driven tool, that I«m going to automate and improve somewhat.
Current verison do have air-logic, but a microcontroller based will have more facilities.

So, I got plenty of air, standard pressure 7bar, filtered, dehumidized, oil free.

My power requirement is about 12V, 1W.

Lifetime also is an issue as this is industrial, and noise must not be too high.
Cost is always an issue...
Maximum alowed airelectric generator size is 0,5 litre.

I have sketched of a number of solutions, but nu really good.
Unfortunately i have no rotating part on that tool, (just cylinders) and also the sensors need power when tool is at rest.

Probably someone have been thinking about this before, and a good place to ask is this list  :)

So...??

Thanks in advance.

/Morgan
Morgan Olsson                   spam_OUTmorgans.rtTakeThisOuTspamtelia.com
Morgans Reglerteknik, HŠllekŒs, 277 35 KIVIK, SWEDEN
    tel +46(0)414-446620, fax +46(0)414-672324

2000\04\13@181139 by Alice Campbell

flavicon
face
How about making a fat place in an air hose, and putting in
a muffin fan wired to work as a generator?

alice

{Quote hidden}

2000\04\13@183030 by Morgan Olsson

picon face
Alice Campbell wrote:
>How about making a fat place in an air hose, and putting in
>a muffin fan wired to work as a generator?

Sorry, I don«t know what muffin fan is?
(except muffin is a kind of cake here in Sweden...)

Those brushless type fans in square form?

Been thinkign about them.

Probably a good 24V 5W rated will give, when driven by air to same rpm as originally working as fan, and drive logic substituted for a fullbridge rectifier, wild guess after all losses, about 12V >1W.

However it will only use a wery small fraction of the energy in the air; the air pressure used will be only a fraction of air supply pressure, rest will just make turbulence.

(if I could find a small turbine with some hundred thousand rpm, and a genertor for that speed, then it will maybe build up a countepressure and be effective working like a "real" turbine.  Would be no cheap stuff...)

I read some company make a ejector-kind of "flow amplifier", maybe that is a good idea to give more flow to the fan / lowering air supply requirements?


/Morgan

2000\04\13@185731 by Andrew Hooper

flavicon
face
I was doing something similar, needed a water tight housing and with no
external connections
i needed to supply power to the circutry, the best way to do this was to
totally seal the circut
and include an inductiveley coupled charging system, this would charge a
supercap or a
set of cells, and power the circut, the reason for the supercap and/or cells
is that if there
is any deviation on the power being supplied its not reflected in the
performance of the
circut.

Let me know if you ned a circut, i think i have it kicking around
somewhere..(if youre lucky)
from memory i was supplying about 2 volts over a distance of about 5 to
10mm.
this could be altered by changing the turns on the transformer.

Regards
Andrew


>I«m working on a project where the customer don«t want electric connection.
>And no batteries needing to charge, switch or anything like that either.
>Too dark/small/dusty to use solar power.
>
>It«s a kind of moving hose connected pressure air driven tool, that I«m
going to automate and improve somewhat.
>Current verison do have air-logic, but a microcontroller based will have
more facilities.
>
>So, I got plenty of air, standard pressure 7bar, filtered, dehumidized, oil
free.
>
>My power requirement is about 12V, 1W.
>
>Lifetime also is an issue as this is industrial, and noise must not be too
high.
>Cost is always an issue...
>Maximum alowed airelectric generator size is 0,5 litre.
>
>I have sketched of a number of solutions, but nu really good.
>Unfortunately i have no rotating part on that tool, (just cylinders) and
also the sensors need power when tool is at rest.
>
>Probably someone have been thinking about this before, and a good place to
ask is this list  :)
>
>So...??
>
>Thanks in advance.
>
>/Morgan
>Morgan Olsson                   morgans.rtspamKILLspamtelia.com
>Morgans Reglerteknik, HŠllekŒs, 277 35 KIVIK, SWEDEN
>     tel +46(0)414-446620, fax +46(0)414-672324

2000\04\13@185738 by CUTTLER!

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face
A general "square" DC brushless muffin fan will not work because it takes energy and
pulses it around a circular ring of magnetic material.

You WILL need a fan that HAS brushes before you can use it as a non efficient DC
generator.  Further, if you get a small Radio Shack hobby motor and put a "fan" on
it, it should generate enough to run a PIC after filtering and regulation.  Make sure
it is spinning in the right direction too.

Good Luck!

>>How about making a fat place in an air hose, and putting in
>>a muffin fan wired to work as a generator?
>
>Those brushless type fans in square form?

2000\04\13@190351 by l.allen

picon face
Morgan Wrote
>
> Those brushless type fans in square form?
>
> Been thinkign about them.
>
> Probably a good 24V 5W rated will give, when driven by air to
>same rpm as originally working as fan, and drive logic
>substituted for a fullbridge rectifier, wild guess after all
>losses, about 12V >1W.
>
> However it will only use a wery small fraction of the
> energy in the air; the air pressure used will be only a
>fraction of air supply pressure,/Morgan

Yes, those fans are high speed air movement, low
pressure types. A higher pressure fan would be a cage
type But I suspect that would be inefficient with a
compressed air source.
I would investigate a little piston driven air engine, low air
flow with excellent use made of the air pressure. The
shaft output will drive a little permanent magnet generator.
If there isnt anything obvious available I would have a go
at reverse flowing air though a model airplane engine or
normal flow through a model steam engine (at model
shows here I have seen compressed air used for
demonstration of steam engines indoors).
I confess I havent done this but I would try it in your
circumstance.


_____________________________

Lance Allen
Technical Officer
Uni of Auckland
Psych Dept
New Zealand

http://www.psych.auckland.ac.nz

_____________________________

2000\04\13@194545 by Thomas McGahee

flavicon
face
Are you looking for an off-the-shelf solution, a kluge,
or a new kind of product?

If I were designing this sort of thing from scratch I would
first of all take note of your requirement that the device
produce electricity even when the actual tool was at rest.
That requirement means that whatever kind of generator I come
up with has to run continuously. So you are talking here
about a small efficient generator that consumes little
air when idling, but probably a fair amount when activating
other items such as solenoids.

While the first thing that comes to mind is a rotary
generator, this would probably NOT be a good choice
here. Instead I would opt for a reciprocating style
generator. Instead of having a rotor that rotates
next to a set of magnetic poles, you would have an internal
cylinder that carries the magnetic field. This could be
simply a very small but strong cylindrical bar magnet.
They make some amazing rare-earth magnets for things like
hard drive head positioners. You could probably make
one that had a cylinder say 1/4" in diameter and 1/2"
long. This would be connected directly to  a little
piston assembly. When air under pressure is applied, the
cylinder would first move in one direction, and then
a set of two mechanical valves would be opened and closed
in sequence uch that the inner cylinder constantly moved
back and forth due to the change in which valve was letteing the air
in, and which valve was letting the air out.

Surrounding the reciprocating magnet would be a stationary
coil with many turns of fine wire. As the magnet went back
and forth the coil would develop an AC voltage. Low voltage
diodes would full-wave rectify the voltage and on the
board with the PIC would be some reasonable sized capacitors
to reduce ripple. Because the output of the generator is
true AC you could use straightforawrd voltage multiplier
techniques (such as the marx multiplier) to raise the voltage
to any desired level.

A receprocating cylinder generator can run at fairly low
speeds and still do a good job of producing electrical
power. A simple small air regulator would ensure that
voltage was fairly constant. Note that such a device would
probably be better off running in "parallel" with the main
tool, rather than in "series" with it, though both
arrangements can be made to work.

So where do you buy one of these things? I don't know.
I don't even know if anyone manufactures a device like
I described. If not, maybe someone should.

Fr. Tom McGahee

{Original Message removed}

2000\04\13@235303 by Spehro Pefhany

picon face
At 11:50 PM 4/13/00 +0200, you wrote:
>I«m working on a project where the customer don«t want electric connection.
>And no batteries needing to charge, switch or anything like that either.
>Too dark/small/dusty to use solar power.

There are such things as air motors, used in process control equipment
where electricity is too dangerous. I think the price may be too high
for your application, though, and you'd need a generator too.

An air-powered die grinder sells for about US$10 retail, Asian made,
with the following specs:

Operating pressure: 90 PSI
No-load speed: 25,000 RPM
Air consumption: 3 CFM
Air inlet: 1/4'' NPT
Collet size: 1/4''

Maybe you could couple that to a generator to get the power you need.

Best regards,


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Spehro Pefhany --"it's the network..."            "The Journey is the reward"
.....speffKILLspamspam.....interlog.com             Info for manufacturers: http://www.trexon.com
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=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

2000\04\14@003140 by Terry

flavicon
face
The shaker flashlight has just the mechanism. 1 minute of shaking gives 5
minutes of LED illumination. The link is below.

http://www.y2ksurvivalfood.com/starlight.html

Cheers
Terry


At 07:46 PM 4/13/00 -0400, you wrote:
{Quote hidden}

>{Original Message removed}

2000\04\14@015653 by R. Monsees

flavicon
face
Did anyone ever buy one to take it apart ?  Just to see
how it's working ?

Reelf

Terry schrieb:
{Quote hidden}

> >{Original Message removed}

2000\04\14@023508 by David Lions

flavicon
face
Read the page:

"The energy of motion is
                      efficiently transformed into electrical energy by
means of repeatedly passing a high-power rare earth magnet through a coil
of wire. This energy is stored
                      in a capacitor which powers the whitelight LED."

Curiosity satisfied.  Now us nerds don't have to buy one! ;)


At 07:55 AM 4/14/00 -0700, you wrote:
{Quote hidden}

David Lions
Lab Technician
Miva Corporation

2000\04\14@024757 by David Lions

flavicon
face
LOL!  And reading further:

"Warning: A strong magnetic field surrounds StarLight. Keep at least 16"
(40 cm) away from magnetic storage

media, video displays, navigation equipment, and other items sensitive to
magnetic fields. "

Navigation equipment?

You are lost in the jungle, running low on food and water.  Your radio and
mobile phone have mysteriously stopped working.  Navigating through the
dark with your compass and StarLight, you notice you are travelling around
in circles...


At 07:55 AM 4/14/00 -0700, you wrote:
{Quote hidden}

David Lions
Lab Technician
Miva Corporation

2000\04\14@030343 by David VanHorn

flavicon
face
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1


>"Warning: A strong magnetic field surrounds StarLight. Keep at least 16"
>(40 cm) away from magnetic storage

Takes 700G to erase a disk, those magnets probably have a surface peak of
maybe 2000, They would probably be safe at 1 inch.  (Sanity check, there's
a pair of such magnets, probably much larger, inside your hard drive)

Compasses are another matter. Inexpensive ones can have their "north"
re-written with fairly low fields.
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iQA/AwUBOPbcaIFlGDz1l6VWEQLkkQCgvqXZEzdSLmC3o6PF1kkZUzXstkAAnRWW
U9AJH0h/Spy2n2LRkNOFvG1u
=rS45
-----END PGP SIGNATURE-----

2000\04\14@060745 by Alan B Pearce

face picon face
>Sorry, I don4t know what muffin fan is?
>(except muffin is a kind of cake here in Sweden...)

>Those brushless type fans in square form?

That is exactly what they are, and a brushless motor will not work as a
generator, as it requires a DC input, which in turn drives electronics which
generate multiple phase AC to drive the motor.

2000\04\14@074218 by paulb

flavicon
face
CUTTLER! wrote:

> A general "square" DC brushless muffin fan will not work because it
> takes energy and pulses it around a circular ring of magnetic
> material.

 Bong!  Missed the boat on that one!  Alice's suggestion of running
such a fan as a generator by adding a bridge rectifier is apt.

> You WILL need a fan that HAS brushes before you can use it as a non
> efficient DC generator.

 Non-efficient generator?  Either way, Bong!  Missed the boat on that
one too!

 Point is, just like the fans, for these lightweight devices, omitting
the friction from brushes increases efficiency tremendously - in fact
that's *exactly* why they are brushless.

 That's also why, though they still have brushes, but small ones, to
run on slip rings, commutators were lost from automotive generators
years ago.

Alan B Pearce similarly wrote:

> That is exactly what they are, and a brushless motor will not work as
> a generator, as it requires a DC input, which in turn drives
> electronics which generate multiple phase AC to drive the motor.

 Sorry Alan, while they will not work *as is*, a bridge rectifier (2,
3, or more phase) is extremely simple to implement.  Using Schottky
rectifiers, it can be very efficient too.

 The average computer fan is rated 12V, 0.15A, making it 1.8W rating.
(Mind you the one I just grabbed off the shelf is rated twice that.)
Efficiency is probably in the order of 50%.  It does however suggest
that it could indeed generate 12V at 1W.

Morgan Olsson wrote:

> Probably a good 24V 5W rated will give, when driven by air to same rpm
> as originally working as fan, and drive logic substituted for a
> full bridge rectifier, wild guess after all losses, about 12V >1W.

 It probably wouldn't be all *that* inefficient.  The *big* problem
would be - it's just so really, really *big*!

> I read some company make a ejector-kind of "flow amplifier", maybe
> that is a good idea to give more flow to the fan / lowering air supply
> requirements?

 For slow speed fans, which is what the computer blowers are (not to
make too much noise), that could be useful, it's just a venturi
entrainer - the high-speed (pressure) jet develops suction and pulls a
large volume of air through the venturi.

 I'd go rather with Father Tom's concept - the "shaker-torch" system.
Few moving parts, slow (comparatively) speed, minimal noise.  But I'd
really revise your 1W rating downward, using miniaturised servo valves
(not that I know who'd make these, but if you can make the air tool with
fluid logic, presumably you can make the valves) and putting the CPU to
sleep whenever possible.  By so doing, operation from a supercap should
be possible.

 When the tool is actually in use (the only time you should need to
power your valves), its (series) discharge air should power the shuttle
generator and charge the cap.  Also, using a hysteretic (bipolar
latching) main valve should allow the electronics to switch the air on
when reservoir capacitor is too low (dying act) and restart the
generator.  Of course, if the air is shut off, the generator won't
operate and the tool will be dead until it is reconnected, but that's
the expected manner of operation anyway.

David VanHorn wrote:

>> "Warning: A strong magnetic field surrounds StarLight. Keep at least
>> 16" (40 cm) away from magnetic storage

> Takes 700G to erase a disk, those magnets probably have a surface peak
> of maybe 2000, They would probably be safe at 1 inch.  (Sanity check,
> there's a pair of such magnets, probably much larger, inside your hard
> drive)

 You're quite right, but if I had one, I'd be very careful about it.
*Unlike* the hard drive, it probably doesn't have a full magnetic
circuit, due to weight and complexity restrictions.  I think they are
litigation-conscious (previously covered thread).
--
 Cheers,
       Paul B.

2000\04\14@080511 by Alan B Pearce

face picon face
>  Sorry Alan, while they will not work *as is*, a bridge rectifier (2,
>3, or more phase) is extremely simple to implement.  Using Schottky
>rectifiers, it can be very efficient too.

I take it you are assuming taking the electronics out of it. NOT ONE PERSON has
stated this so far. There is no way you will be able to make a brushless DC fan
run as a generator unless you do. The only way you might do it with attacking
the fan is to use an AC mains powered one, but these generally use a shaded pole
motor with no permanent magnet.

Perhaps a better solution is to have a wire in an airline and pick off the
static voltage as the air rushes past. regulate it with a switching regulator
down to 5V. Wont have enough power to run solenoids though, just the PIC.

I come back to the original question - why can you not use an external source of
power? There must be a cable to get information from the micro out to the
outside world, or control info in from a switch panel or something. Why not
bring power in with that? There is no way I can see that you are going to have
enough power available otherwise to keep a solenoid pulled in for more than a
very short length of time.

2000\04\14@085939 by Andrew Kunz

flavicon
face
>I take it you are assuming taking the electronics out of it. NOT ONE PERSON has

Of course, this is obvious.  You want it to be a generator, not a motor.  That
means the motor drive circuitry has to go.  Sometimes the obvious doesn't need
to be stated.  (Sometimes it does)

Andy

2000\04\14@103107 by Michael Rigby-Jones

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face
part 0 2869 bytes
<P><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">Dr Paul Webster wrote:</FONT>
</P>
<UL>
<P><FONT SIZE=2 FACE="Arial">&nbsp; Point is, just like the fans, for these lightweight devices, omitting</FONT>
<BR><FONT SIZE=2 FACE="Arial">the friction from brushes increases efficiency tremendously - in fact</FONT>
<BR><FONT SIZE=2 FACE="Arial">that's *exactly* why they are brushless.</FONT>
</P>

<P><FONT SIZE=2 FACE="Arial">&nbsp; That's also why, though they still have brushes, but small ones, to</FONT>
<BR><FONT SIZE=2 FACE="Arial">run on slip rings, commutators were lost from automotive generators</FONT>
<BR><FONT SIZE=2 FACE="Arial">years ago.</FONT>
</P>
</UL>
<P><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">I respectfully disagree on this one.&nbsp; I don't suppose the manufacturers of those fans are really concerned about efficiency.&nbsp; Fans are almost always used in line powered equipment, not battery operated.&nbsp; Obviously they have to keep current consumption to reasonable levels, but the odd 20 or 30 milliamps here and there won't matter.</FONT></P>

<P><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">What is of far greater consequence is both the EMI aspect, and longevity.&nbsp; Motors with brushes can generate a lot of interference, and brushes will obviously be one of the first things to wear.</FONT></P>

<P><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">The increase in efficiency of an automotive alternator stems, I suspect, from the fact that the generated current doesn't have to pass through the commutator/brushes as it does in a dynamo.&nbsp; The current is generated in the field windings which are excited by the rotor.&nbsp; If the alternator used the field for excitation and used the rotor for generation I suspect it wouldn't be much more efficient than a dynamo.</FONT></P>

<P><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">All the same, it would be interesting to see how much power a typical 4&quot; fan could produce.&nbsp; The main difficulty is getting them apart without breaking something.&nbsp; As with most far eastern electronic items, they were designed to be put together once, and never taken apart.</FONT></P>

<P><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">Regards</FONT>
</P>

<P><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">Mike</FONT>
</P>

</BODY>
</HTML>
</x-html>

2000\04\14@113347 by CUTTLER!

flavicon
face
My good friend and colleague,
If you have one of these in your shop, why don't you waste a couple of hours and
just
SEE why it wont work.

I'm sure that you could "get" it to work but it is not worth the hassle.



 > A general "square" DC brushless muffin fan will not work because it
> > takes energy and pulses it around a circular ring of magnetic
> > material.
>
>   Bong!  Missed the boat on that one!  Alice's suggestion of running
> such a fan as a generator by adding a bridge rectifier is apt.

2000\04\14@115849 by Andrew Kunz

flavicon
face
Carl,

Why don't you explain it.

Last time I checked, moving a magnetic field with a coil in it generated
electricity.  Didn't matter if the magnets were moving or the coil.

Nobody said he needed to use all the poles, or that the muffin fan had to be
unchanged.

Or maybe you know something about electricity generation that has been hidden
from the eyes of the power companies.

I'm really curious to know why a brushless motor (sans the commutation
electronics) won't generate volts.  If that's so, I will have to recall some
products because they suddenly won't work any more.

Andy









CUTTLER! <EraseMEcarlspam_OUTspamTakeThisOuTMMCABLE.COM> on 04/14/2000 11:36:10 AM

Please respond to pic microcontroller discussion list <PICLISTspamspam_OUTMITVMA.MIT.EDU>








To:      @spam@PICLISTKILLspamspamMITVMA.MIT.EDU

cc:      (bcc: Andrew Kunz/TDI_NOTES)



Subject: Re: Air powered electronics








My good friend and colleague,
If you have one of these in your shop, why don't you waste a couple of hours
and
just
SEE why it wont work.

I'm sure that you could "get" it to work but it is not worth the hassle.



 > A general "square" DC brushless muffin fan will not work because it
> > takes energy and pulses it around a circular ring of magnetic
> > material.
>
>   Bong!  Missed the boat on that one!  Alice's suggestion of running
> such a fan as a generator by adding a bridge rectifier is apt.

2000\04\14@120530 by CUTTLER!

flavicon
face
Good Friend,
I think we are both hitting the drum from different angles,

I'm saying that it wont work out of the box,
Your saying that it will work with modifications.

It's pretty much the same thing isn't it?

>
> Nobody said he needed to use all the poles, or that the muffin fan had to be
> unchanged.
>

2000\04\14@121344 by Andrew Kunz

flavicon
face
Didn't realize you were still stuck on "out of the box."  It's pretty obvious
that you have to remove the commutation electronics (FETs, sequencer, etc) to
get it to work.  You also have to remove the FETs which cause a brushed motor to
run in order to use it as a generator.  Of course, this is mixing apples and
apples (motor + drive electronics  == motor + drive electronics).

If you're trying to compare apples (motor + drive electronics) to oranges (motor
alone) then obviously you'll have problems.

Andy










CUTTLER! <KILLspamcarlKILLspamspamMMCABLE.COM> on 04/14/2000 12:08:02 PM

Please respond to pic microcontroller discussion list <RemoveMEPICLISTTakeThisOuTspamMITVMA.MIT.EDU>








To:      spamBeGonePICLISTspamBeGonespamMITVMA.MIT.EDU

cc:      (bcc: Andrew Kunz/TDI_NOTES)



Subject: Re: Air powered electronics








Good Friend,
I think we are both hitting the drum from different angles,

I'm saying that it wont work out of the box,
Your saying that it will work with modifications.

It's pretty much the same thing isn't it?

>
> Nobody said he needed to use all the poles, or that the muffin fan had to be
> unchanged.
>

2000\04\14@123429 by CUTTLER!

flavicon
face
Actually I kind of like the Die Grinder hooked to something Idea.  Although having
used one, It is rather loud.

If solar power is out, How about a water wheel to power a PIC board?  Or a clock
works mechanism that one winds up once a day?  Maybe a clock works mechanism that
shakes a flashlight so it can shine on a solar cell that powers a motor that turns
another motor that is acting like a generator so that it can be turned into power to
run a PIC board?

:-)
Carl Bright
TakeThisOuTcarlEraseMEspamspam_OUTmmcable.com
http://home.mmcable.com/cuttler/


> Didn't realize you were still stuck on "out of the box."  It's pretty obvious
> that you have to remove the commutation electronics (FETs, sequencer, etc) to
> get it to work.  You also have to remove the FETs which cause a brushed motor to
> run in order to use it as a generator.  Of course, this is mixing apples and
> apples (motor + drive electronics  == motor + drive electronics).
>

2000\04\14@152827 by William Chops Westfield

face picon face
A disk spindle motor has nice bearings and usually doesn't include the
multi-phase driver electronics, and so will make a fine (three phase,
usually) generator.  I even watched one do so on a scope recently, which was
pretty cool.  It's also designed to operate at moderately high speeds (3000
to 10000 rpm, these days?) so it'd be a good candidate for being driven by
an air turbine, I think.

BillW

2000\04\14@184529 by Jeffrey D Spears

flavicon
face
William;

Just read your note below. Picked up a spindle motor, hooked up the
scope and gave it a spin. Gots 8Vpp just from spinning by hand. I
may have to hook this up to my steam engine and run a pic that way!

Or maybe that is the answer to the thread? Have the individual get
a small model steam engine, perhaps a Cheddar like mine(burns butane,
contains water injector pump) hooked up to one of your little disk
drive spindle motors to run the pic and a couple other small loads?
No?

http://www.yesteryeartoys.com (Cheddar marine steam plants)

ok..jef


On Fri, 14 Apr 2000, William Chops Westfield wrote:

{Quote hidden}

Jeffrey D. Spears
University of Michigan
College of Engineering

``Double-E, can't spell gEEk without it!''
                       -Captain Gerald M. Bloomfield II, USMC
                        (my brother)

2000\04\14@185804 by William Chops Westfield

face picon face
   Have the individual get a small model steam engine, perhaps a
   Cheddar like mine hooked up to one of your little disk drive
   spindle motors to run the pic and a couple other small loads?

Come to think of it, most (all?) steam engines will run off pretty much
any source of high-pressure gas, right?  And there are model airplane
motors that will run off a CO2 cartridge, and even a set of toys on the
market currently that drive a propellar using a (logical) soda bottle
full of compressed air (from a bicycle-style pump. "Air-hogs", I think
they're called.)

BillW

2000\04\14@194849 by Jeffrey D Spears

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face
Bingo! You hit the nail on the head.

A Wilesco steam motor using pressurized air. I know these can
generate a couple of hundred milliwatts. Come up with an oil
injector in the 45psi air source.



On Fri, 14 Apr 2000, William Chops Westfield wrote:

{Quote hidden}

Jeffrey D. Spears
University of Michigan
College of Engineering

``Double-E, can't spell gEEk without it!''
                       -Captain Gerald M. Bloomfield II, USMC
                        (my brother)

2000\04\15@040434 by Arthur

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face
That's *It* poster says they have compressed air on sie
Art
from RemoveMEwildspamTakeThisOuTblueyonder.co.uk

----- Original Message -----
From: William Chops Westfield <billwEraseMEspam.....CISCO.COM>
To: <EraseMEPICLISTspamMITVMA.MIT.EDU>
Sent: Friday, April 14, 2000 11:55 PM
Subject: Re: Air powered electronics


{Quote hidden}

2000\04\15@083535 by Alok Dubey

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is this square brushless fan a stepper motor?.. cause it cant be anythng
else and obviously is an induction motor.. but other than stepper are there
any other DC induction motors?
Alok


> {Original Message removed}

2000\04\15@093241 by paulb

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Alok Dubey wrote:

> is this square brushless fan a stepper motor?

 It is in effect.  Note that stepper motors make quite good (AC)
generators at low rotational speeds.

> cause it cant be anythng else and obviously is an induction motor..

 No, it's not an induction motor.  Stepper motors (including disk drive
spindle motors) use permanent magnet rotors.  Induction motors use an
induced field in the soft iron rotor to develop a reaction torque.
There are tutorials on this on the Web.

> but other than stepper are there any other DC induction motors?

 *Some* dirt cheap fans use a sort of induction motor where the rotor
pole is attracted to the stator pole purely by induced magnetism.  You
can tell these as there is no "cogging" (stepwise resistance) felt as
you spin the shaft by hand when power is off.

 This functions like a simple relay with armature attracted to the pole
piece but torque and efficiency are rather poor due to the limited flux
and operating by attraction only - half of the potential torque is
ignored.
--
 Cheers,
       Paul B.

2000\04\17@100233 by Don Hyde

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face
Judging from the way it cuts and how much air it uses, I'd say my $15 die
grinder would be way overkill.  What you would want is something about 1/10
that size.

> {Original Message removed}

2000\04\17@111412 by MegaBolt

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picon face
May be you would like to share some of your sketches.

Piezo-electric ???
I wonder how those childrens' shoes with blinking LEDs
work.  The LEDs blink when the sole contact ground.

When the tool is at rest is there still 7bar pressure?


CHL

----- Original Message -----
From: Morgan Olsson <RemoveMEmorgans.rtEraseMEspamEraseMETELIA.COM>
To: <RemoveMEPICLISTspam_OUTspamKILLspamMITVMA.MIT.EDU>
Sent: Thursday, April 13, 2000 2:50 PM
Subject: Air powered electronics


> I«m working on a project where the customer don«t want electric
connection.
> And no batteries needing to charge, switch or anything like that either.

2000\04\17@162743 by l.allen

picon face
>
> Piezo-electric ???
> I wonder how those childrens' shoes with blinking LEDs
> work.  The LEDs blink when the sole contact ground.
>

A Piezo Kynar disc flexes, generates a voltage that turns
a fet on and current is drained from an on board (on
shoe?) battery that drives the led.
Alas.. there is insufficient power to drive a led from the
piezo disc direct.
_____________________________

Lance Allen
Technical Officer
Uni of Auckland
Psych Dept
New Zealand

http://www.psych.auckland.ac.nz

_____________________________

2000\04\18@013005 by Josh Koffman

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Lance Allen wrote:

> >
> > Piezo-electric ???
> > I wonder how those childrens' shoes with blinking LEDs
> > work.  The LEDs blink when the sole contact ground.
> >
>
> A Piezo Kynar disc flexes, generates a voltage that turns
> a fet on and current is drained from an on board (on
> shoe?) battery that drives the led.
> Alas.. there is insufficient power to drive a led from the
> piezo disc direct.

I once ripped one of those shoes apart. All that was inside was a clear
plastic block with a round watch battery, a couple LEDs, and a ball
bearing in a channel molded inside the block. When the child took a
step, the bearing slid forward, then back where it made contact with two
wires, lighting the LED, then was pushed forward with a little spring. I
assume this was so the LED could never be constantly lit thereby
draining the battery.

Josh Koffman
RemoveMEjoshyTakeThisOuTspamspammb.sympatico.ca

2000\04\18@061553 by Russell McMahon

picon face
Morgan,

If using a fan as an impeller then the type of fan will have some effect.
The majority of small cooling fans are intended for largish volume and
lowish pressure and typically have 3 blades - you can see space through the
plane of the blade.

Next are semi axial fans where the blades have a degree of twist and the air
starts to be expelled at an angle to the axis of the shaft. Pressure is
higher and air volumes are reduced.
Some light still visible through plane of fan, but less.

Next are units where the air exits fully radially giving highest pressure
and lowest volume.
No light visible through plane of fan.



I imagine that one of the latter comes closest to matching the "impedance"
of your air supply. Using an electrical analog for the air supply, you
effectively have a "high voltage low current" air supply and you are trying
to drive a "low voltage high current" device. The radial fan comes closest
to matching the supply. Such a fan when used as an impeller would be driven
tangentially rather than having the air flow impinge on the flat of the
blades. I'm nit sure of your exact driving arrangement (in there somewhere I
know but too many posts in this thread now :-))

Best of all would (perhaps) be a "Roots blower" which is a positive
displacement device with two interleaving dumbell type rotors. This is a
very high pressure lower volume device.

The closest device in common use is probably a vacuum cleaner rotor. These
are driven by a series motor which is designed to rev up indefinitely until
the load matches the input power. Speeds are much faster than fans which are
synchronously driven ) 30000 rpm?. The "turbine" from a die grinder may also
be useful - and its fairly small. When used in a die grinder it takes far
too much air (and makes a laaarge amount of power).
It just may be that you could build.design a unit with magnetic bearings
inside your budget. Real units with such bearings are complex and take
extensive design effort but in your case the power rating is minimal and
efficiency unimportant. A magnetic bearing has, of course,  a superb design
life.




regards

               Russell McMahon

2000\04\18@085123 by Morgan Olsson

picon face
Russell McMahon wrote:

-snip-


>Using an electrical analog for the air supply, you
>effectively have a "high voltage low current" air supply and you are trying
>to drive a "low voltage high current" device.

Good analogy :)

>  The radial fan comes closest
>to matching the supply. Such a fan when used as an impeller would be driven
>tangentially rather than having the air flow impinge on the flat of the
>blades. I'm nit sure of your exact driving arrangement (in there somewhere I
>know but too many posts in this thread now :-))

Yep.  I have closed both sides of the originally axial fan, and insert the air pretty tangentially, and let the air out in center.

Experimentally found that I got a sligth gain (10%) and less noise if i aim slightly down from original intake, and more to the center.

Reason for not building on an a radial fan are:
More expensive
The fan housing curve is designer for larger flow


>It just may be that you could build.design a unit with magnetic bearings
>inside your budget.

No...

>Real units with such bearings are complex and take
>extensive design effort but in your case the power rating is minimal and
>efficiency unimportant. A magnetic bearing has, of course,  a superb design
>life.

Been thinking of making air bearings, as I already have pressure air, but they will consume some air of course...

/Morgan

2000\04\18@102637 by Wagner Lipnharski

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face
You will be surprised about the "pressure computers", some tinny little
pressure components, gates, switches, that together can do complex
calculations and so on.  I don't know if they still in use, but I saw
some marvelous like that 15 years ago operating in highly explosive
ambient.

IBM was researching "light computers", an array of micro-optical devices
that used only a laser as its main power source. Gates and switches
change state when hit by a photons, and of course they allow or not
photons to go ahead... another science fiction turning to reality. Not a
single microampere of current in such high speed computer.


Spehro Pefhany wrote:
{Quote hidden}

2000\04\18@105022 by Andrew Kunz

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face
Wagner,

Air logic is often still used in many machine shops.  They have 90 pounds
available, and it doesn't short circuit with all the metal chips around.
Clippard was the big name, as I recall, and they're still in business.

Andy








Wagner Lipnharski <RemoveMEwagnerKILLspamspamUSTR.NET> on 04/18/2000 10:22:05 AM

Please respond to pic microcontroller discussion list <PICLISTSTOPspamspamspam_OUTMITVMA.MIT.EDU>








To:      spamBeGonePICLISTSTOPspamspamEraseMEMITVMA.MIT.EDU

cc:      (bcc: Andrew Kunz/TDI_NOTES)



Subject: Re: Air powered electronics








You will be surprised about the "pressure computers", some tinny little
pressure components, gates, switches, that together can do complex
calculations and so on.  I don't know if they still in use, but I saw
some marvelous like that 15 years ago operating in highly explosive
ambient.

IBM was researching "light computers", an array of micro-optical devices
that used only a laser as its main power source. Gates and switches
change state when hit by a photons, and of course they allow or not
photons to go ahead... another science fiction turning to reality. Not a
single microampere of current in such high speed computer.


Spehro Pefhany wrote:
{Quote hidden}

2000\04\18@175021 by paulb

flavicon
face
Wagner Lipnharski wrote:

> You will be surprised about the "pressure computers", some tinny
> little pressure components, gates, switches, that together can do
> complex calculations and so on.  I don't know if they still in use,
> but I saw some marvelous like that 15 years ago operating in highly
> explosive ambient.

 I believe the original poster stated this application was intended to
*replace* such a device.  Nice as they are, electronics is king!
--
 Cheers,
       Paul B.

2000\04\19@032158 by Paul Anderson

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face
On Sat, 15 Apr 2000, Arthur wrote:

> That's *It* poster says they have compressed air on sie
>
BTW, the type of valve used by Air-Hogs toys are called bash valves - very
simple valving system for a steam engine.  Popular with newer steam cars.



---
Paul Anderson - Self-employed Megalomaniac (and resident steam nut)
EraseMEpaulspamEraseMEgeeky1.ebtech.net
http://zephyr.sellad.on.ca/~paul
"As a lover of aircooled VWs, I, of course, am not a radiator fan."
       -- Peter Brow


'Air powered electronics'
2000\05\02@214314 by paulb
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face
A while back there was some ideas being floated for generating electric
power from air to drive some electronic controls.
Well just today I was having a look at the new goodies from MAC TOOLS
and saw that they have an "AIR POWERED LIGHT" to attach to your air
tools to give you light right where you need it.

-The light bulb is only rated at 2.5V .3A
-It is very small and light.
-uses small air volume
-generated noise low
-Canadian Price ~$135.00

Maybe output could be increased? (Using the charging a super cap idea)
Just thought you might be interested.

CUTTLER! wrote:

> A general "square" DC brushless muffin fan will not work because it
<snip>

>  The average computer fan is rated 12V, 0.15A, making it 1.8W rating.
<snip>

> Probably a good 24V 5W rated will give, when driven by air to same rpm
<snip>

> I read some company make a ejector-kind of "flow amplifier", maybe
<snip>

>  I'd go rather with Father Tom's concept - the "shaker-torch" system.
>Few moving parts, slow (comparatively) speed, minimal noise.  But I'd
<snip>

>sleep whenever possible.  By so doing, operation from a supercap should
>be possible.
<snip>

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