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Home > Archive > Alternative Power sources > October 2005 > Conservation of angular momentum, Foucault Pendulum and 'free
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Conservation of angular momentum, Foucault Pendulum and 'free
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| Scott A Crosby 2005-10-09, 9:21 pm |
| On Sun, 09 Oct 2005 12:50:28 GMT, abelshapiro@pinex.com writes:
> In any case, aren't we missing the point here. Its potential for
> generating clean electrical energy must be enormous. If one unit of a
> hundred thousand tons of inert concrete can generate 300 meg/W
> virtually forever without the need of fuel, that has to be considered
> - That's enough for a sizeable city, and is a helluva lot more than
> windmills or solar.
FYI: 300MW is about .1% of what the US uses.
Here's a counterproposal for 'free' energy from a gyroscope. Well, not
free, I believe the force it is exploiting is coming from earth's
rotation, but I suspect there's a mistake somewhere because I don't
think I'm conserving angular momentum.
Put a partially gimballed gyroscope on the equator with its axis of
rotation aimed straight up/down. As earth rotates, the gyroscope will
continue to rotate in the same plane, but the earth will rotate
underneath it flipping it end over end once a day. Now, we only allow
the gyroscope's axis of rotation to rotate through a vertical plane
--- the equator. Now we have a gyroscope whose axis of rotation will
flip end-over-end 360 degrees a day.
Attach a generator, generate electricity.
Ah, it does purporteldy work!
http://www.lhup.edu/~dsimanek/museum/advanced.htm
'gyrogenerator'
Now how do I work out the math for how much energy it would produce?
Scott
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| Scott A Crosby 2005-10-10, 6:21 pm |
| On Mon, 10 Oct 2005 14:47:12 -0400, "Solar Flare" <sflare@hotmail.com> writes:
> "Me" <Me@shadow.orgs> wrote in message
> news:Me-EF6747.09284310102005@netnews.worldnet.att.net...
[color=darkred]
I'm making the general assumption of frictionless bearings. (or
equivalently, in a real device, assuming that it could be scaled up
and bearings chosen such that friction while existant, is sufficiently
low.)
[color=darkred]
> When you extract power from the gyro it stops spinning. There is no
> more power than the power applied to make it spin.
This is a cop-put. In this situation, where and how is the force
applied that would contradict newton's first law and make the gyro
stop spinning?
> The "force" it exibits is at right angles to the applied force. Not
> useful either.
So you're claiming that if I were to stop the gyro's axis of rotation
from rotating in the east/west up/down vertical plane that the only
force it would induce would be a perpendicular force to the
east/west up/down rotation plane? My intuition says that this might be an
explanation. For one thing, being unable to extract energy would be
consistent with the fact that the gyrogenerator doesn't seem to
conserve angular momentum.
Its clear that if the gryo was fully gimballed, it would reorient
itself until its axis of rotation faced directly north/south, only a
finite amount of energy would be produced, and that angular momentum
would be conserved.
> This is not energy but force. Sound familar again?
I knew there was probably a physical bug somewhere, was just trying to
identify where.
Scott
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| Scott A Crosby 2005-10-11, 5:21 pm |
| On 11 Oct 2005 02:48:45 -0700, "Hurricane Guy" <bdt5@cox.net> writes:
> A dumb question from me. Scott, Are you saying that if a gyro was run
> in a fixed position over night, it would flip
I believe a gimballed gyro should, because its rotation would continue
in the same plane, but earth's surface would be changing orientation
underneath it, so from the surface, it would appear to rotate 15
degrees per hour on the equator.
> Does a gimballed gyroscope on the earth keep a relative position in
> relationship to the planet Earth? or to the Sun?
I believe it keeps an absolute orientation in a newtonian world.
> Also as I see it if this were the case, the power it takes to run the
> gyron will be equal to or more than the power to turn the generator.
I'm more interested in whether or not I got the physics right for the
principals it uses instead of the practicalities. (And, even if it
works, at one rotation/day, I *highly* doubt it would be practical.)
Scott
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| Scott A Crosby 2005-10-12, 1:21 am |
| On Tue, 11 Oct 2005 20:50:19 GMT, "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> writes:
> Of course if you perfectly restrain it, then no motion and no energy out.
> Or if you leave it completely unrestrained, movement and no force so still
> no energy out. Find a mid-point and you get *some* movement, with *some*
> force. The energy extracted comes from the motion of the planet it's
> mounted on (i.e. the Earth slows it's rotation an infitesimal amount).
There is something incomplete in the explanation: What about
conservation of angular momentum.
Another issue is that the sidewise force induced by the gyroscope
should also affect the rotation of the planet --- altering the axis of
rotation and/or the velocity --- and that must be subject to
conservation of energy.
I don't think it works, but I can't find out why.
Scott
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| Dan Bloomquist 2005-10-12, 2:21 pm |
|
Scott A Crosby wrote:
> On Tue, 11 Oct 2005 20:50:19 GMT, "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> writes:
>
>
>
>
> There is something incomplete in the explanation: What about
> conservation of angular momentum.
>
> Another issue is that the sidewise force induced by the gyroscope
> should also affect the rotation of the planet --- altering the axis of
> rotation and/or the velocity --- and that must be subject to
> conservation of energy.
>
> I don't think it works, but I can't find out why.
Hi daestrom, Scott,
It doesn't work. When you restrain precision there is no counteracting
force. The gyro will move freely. If you have a toy gyro try it. There
is a counter torque at first and then it will suddenly break free.
> I believe it keeps an absolute orientation in a newtonian world.
Best as we can tell, the universe as a whole. Newton's first law.
http://www.griffithobs.org/exhibits...m/pendulum.html
My favorite:
http://www.mathpages.com/rr/rrtoc.htm
http://www.universetoday.com/am/pub...b_finished.html
> Scott
Best, Dan.
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| Scott A Crosby 2005-10-12, 9:21 pm |
| On Wed, 12 Oct 2005 20:28:20 GMT, "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> writes:
>
> What you say doesn't make any sense to me. Restraining the east-west
> direction generates a force on the axis, perpendicular to the axis, as the
> earth rotates during a day. If left un-restrained in the north-south
> direction, the axis would simply tilt north/south. If this motion is
> restricted, but allowed through some resistance, you have a north/south
> motion through a resistance (i.e. work).
If we tried this, the gyroscope will precess until it its axis of
rotation is oriented on a north-south axis. At which time, it will
remain unaffected by earth's rotation. Also, the gyroscope will be
slowed down by one rotation per day, aka, $x$ rotations forward per
day and one rotation backward from earth's rotation. And conservation
of energy tells me that that one rotation difference/day is where the
energy it produces comes from.
This situation also fully converges angular momentum from earth's
rotation, spin the gyro up. extract energy from precessing, spin down
a slightly slower gyro, and you get back exactly the energy you put
in, and the earth doesn't change rotation velocity.
Unworkable.
But what about the different situation where it is completely
restrained in the north-south direction to keep this from happening,
and partially restrained in the east-west direction.
Scott
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| Dan Bloomquist 2005-10-12, 9:21 pm |
|
daestrom wrote:
> "Dan Bloomquist" <public21@lakeweb.com> wrote in message
> news:_0b3f.9636$cg.2728@news02.roc.ny...
>
>
> What you say doesn't make any sense to me. Restraining the east-west
> direction generates a force on the axis, perpendicular to the axis, as the
> earth rotates during a day. If left un-restrained in the north-south
> direction, the axis would simply tilt north/south. If this motion is
> restricted, but allowed through some resistance, you have a north/south
> motion through a resistance (i.e. work).
Yes. But this was not what I was thinking...
>
> Are you saying there is no significant force available in the north/south
> directions when completely restrained in the east/west?
No. I was considering the case where the n/s axis is restrained and
power was expected by using the force from a half revolution/day from
the e/w axis. In this case the force is non existent.
> This system doesn't require gravity, it merely taps into the kinetic energy
> of the earth's rotation. Again, I don't know that it is 'practical', but I
> see no reason why it wouldn't at least 'work'.
>
> The one problem I see is that if the axis is allowed to move so far that it
> parallel's the earth's axis of rotation, then further rotation of the earth
> will not cause any further precesion. You would have to stop the spinning
> rotor, reset the axis, then spin up the rotor again.
And why I wasn't considering this case. You would only get a few hours
of force before the spin axis became parallel with the earth's axis.
I've been wanting to get a powerball to play with for some time. 
> daestrom
Best, Dan.
P.S. I've joined the maxim forum so it won't be long...
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| Dan Bloomquist 2005-10-12, 10:21 pm |
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Scott A Crosby wrote:
>
> But what about the different situation where it is completely
> restrained in the north-south direction to keep this from happening,
> and partially restrained in the east-west direction.
If you constrain the n/s axis completely, then there will be no torque
on the e/w axis. If a gyro isn't allowed to precise the torque disappears.
> Scott
Best, Dan.
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| Scott A Crosby 2005-10-17, 9:21 am |
| [[ Trimmed the followups ]]
On Fri, 14 Oct 2005 12:29:18 GMT, "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> writes:
> "Scott A Crosby" <scrosby@cs.rice.edu> wrote in message
> news:oydvf02mi6m.fsf@bert.cs.rice.edu...
> Yes, I identified this issue in the paragraph you snipped. One would have
> to stop the spinning rotor, and reset the axis, then spin the rotor back up
> again. Nice of you to simply parrot what I've already discussed. Or didn't
> you bother to read the whole message?
I'm going with the principal that there's a fatal flaw, which seems
certain, then I'm trying to figure out where it is.
I'm certain there must be a flaw because the gyrogenerator violates
the conservation of angular momentum. If it is extracting energy from
earth's rotation, it would have to slow that rotation. Where is that
angular momentum disappearing to?
Ergo, either newton's laws are wrong, or there is something that is
being overlooked.
>
> Nope. Come now, apply some analysis to the situation. Spin the rotor at
> 10000 RPM. That is 1.44e+7 revolutions per day. From this, you subtract 1
> and think it is some significant amount? Besides, as I've said before,
> you'll have to stop the rotor and reset the axis when it reaches N-S and
> restart the rotor after resetting the axis. At the very best, this is not
> even 12 hours, so you've really only 'lost' 1/2 revolution. (start the axis
> tilted towards the south and allow it to precess to the north).
If the gyro is spun up to 1.44e+7 revolutions per day and despun to
1.44e+7-1 revolutions per day, then energy has been removed from the
system. Given that our generator performs work as its axis of rotation
precess, then conservation of energy makes it seem likely the work
done in precessing is exactly equal to that lost rotational energy.
And yes, I'm assuming that we spin up the gyro's, let the axis
precess, and then despin the gyro's, change the axis of rotation, and
repeat.
> The forces applied to spin the gyro up are not in the same plane as the
> earth's axis. Spinning up the gyro while mounted vertically on the equator
> does *not* increase/decrease the spin of the earth. If anything, the force
> will act to precess the planet since the torque to spin up the rotor is at
> right angles to the earth's axis. But stopping the rotor to reset it will
> require a torque that *is* aligned with the planet's axis (since the gyro's
> axis has now rotated)
I think we can get rid of this complication if we assume that the
gyroscope's are spun up in counter-rotating pairs.
>
> Theoretically, or practically? I've already conceded that 'practically' it
> probably can't be made to work. But the theory is still valid.
I think it is theoretically incomplete because it seems to violate
conservation of angular momentum of the earth.
Scott
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| Dan Bloomquist 2005-10-17, 9:21 pm |
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Bill Ward wrote:
>
> Or suppose you go to the North pole and install your gyro
> with the axis restrained to horizontal, mounted on a geared
> lazy susan to allow the earth to rotate beneath it....
Hi Bill,
It doesn't work. If you constrain the precision of a gyro it does not
create a force. It moves freely.
> Bill Ward
Best, Dan.
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