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Author Topic: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant  (Read 823459 times)

hansvonlieven

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #990 on: April 21, 2009, 02:44:10 AM »
It's not a matter of energy spent. I gave an example somewhere in the earlier pages (don't remember what page it was) with a ball losing the same energy but when constraints are imposed the ball is displaced substantially sideways which doesn't occur without constraints. Modeling the same constraints is crucial.

Displacing a weight horizontally takes very little energy, it is still a loss situation though and does not gain you anything.

Hans von Lieven

Omnibus

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #991 on: April 21, 2009, 03:01:19 AM »
Displacing a weight horizontally takes very little energy, it is still a loss situation though and does not gain you anything.

Hans von Lieven

Gains you displacement. It's all about displacement under the action of a force. Nothing more than that.

persume

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #992 on: April 21, 2009, 05:50:18 AM »
AquariuZ, great video links at the bottom of your posts.

Omnibus

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #993 on: April 21, 2009, 07:41:13 AM »
@All,

Here's a model using @broli's method with forced trajectory (see attached). This doesn't work. A counter clockwise tendency at the start is again observed, however. Also, could it be that this forced trajectory is constraining too tightly the spheres, compared to the previous example where spheres had some leeway within the grooves?

fletcher

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #994 on: April 21, 2009, 07:50:39 AM »
If you get a 'zero runner' i.e. something that turns [due torque] then measure its velocity in rpm - see if it accelerates then slows etc - if it holds its rpm or increases then add a torque motor to the sim with a few Newtons of load - if it still accelerates then you have a good chance that you have a winner - OR - you may have to look even more closely at the logic of the build ....

hansvonlieven

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #995 on: April 21, 2009, 09:22:14 AM »
Gains you displacement. It's all about displacement under the action of a force. Nothing more than that.

In a gravity device only upward vertical displacement injects energy. The question is how much does it cost you to do it. Horizontal displacement gets you nothing.

Hans von Lieven

EDIT:

Below there is a way to achieve the same trajectory for the weights in a way that WM2D can cope with. It still does not work though.

AquariuZ

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #996 on: April 21, 2009, 12:22:21 PM »
AquariuZ, great video links at the bottom of your posts.

It´s up to us.

AquariuZ

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #997 on: April 21, 2009, 12:51:31 PM »
Below there is a way to achieve the same trajectory for the weights in a way that WM2D can cope with. It still does not work though.

That´s creative, thanks.

Omnibus

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #998 on: April 21, 2009, 01:04:59 PM »
Quote
In a gravity device only upward vertical displacement injects energy.
...
Horizontal displacement gets you nothing.

Exactly. What we’re looking for here is to find a construction which, at the expense of no energy will constantly bring a given generalized weight in a position to be displaced downwards under the force of gravity.

As for the construction you’re offering, it obviously isn’t the one we’re looking for and has long been out of consideration. Neither is it reproducing what’s being discussed. Do it properly, get rid of the driving weight, turn on air resistance (AR), as an already known requirement for a realistic model, set the rigid joints (RJ) to Measurable, as an already mandatory requirement for a proper rendering of a model, and you’ll get what’s trivially expected from weights constrained to a circular pattern (see first attachment). That isn’t the case discussed here.

As was shown, even a construction with somewhat more relaxed rigid constrains than yours, that using @broli’s forced trajectory, doesn’t work (see second attachment).

What seems to work is a model which allows somewhat looser behavior (up to a point) of the weights at certain sections of the trajectory, as in the third attachment.

Omnibus

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #999 on: April 21, 2009, 01:08:15 PM »
Another quirk of WM2D. The device cannot possibly work as drawn. If you imagine a vertical line through the axle you will see that there is more torque on the right hand side than on the left, yet the device rotates to the left. And that is without taking friction into account.

Hans von Lieven

Let me mention once again. The vertical you've drawn is to the left of the vertical passing through the constantly changing its position center of mass of the system. It is that second vertical that you should use in setting up your inequality.That's a remark in addition to the difference-in-constraints remark and to what Stefan said.

Omnibus

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #1000 on: April 21, 2009, 01:26:39 PM »
@AquariuZ,

Whatever happened to that governmental official? Seems like he went back to sleep on his desk. Didn't they say that by law the answer will be given in two days?

Omnibus

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #1001 on: April 21, 2009, 03:25:07 PM »
@AquariuZ and @Cherryman,

Would be interesting to replace the wheel in what seems to be the working model (per @eisenficker2000 design) with a hockey-stick grooved wheel, to get a slight idea where @Dusty might be heading.

Cherryman

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #1002 on: April 21, 2009, 03:25:33 PM »
@AquariuZ,

Whatever happened to that governmental official? Seems like he went back to sleep on his desk. Didn't they say that by law the answer will be given in two days?

I Think the MIB stept in  :o

Omnibus

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #1003 on: April 21, 2009, 03:29:53 PM »
I Think the MIB stept in  :o

Well, MiB's are Mylow's specialty. As a MiB free country such as Holland, the only possibility are bureaucrats sleeping on their desks (bureaus), it seems.

mondrasek

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Re: Sjack Abeling Gravity Wheel and the Worlds first Weight Power Plant
« Reply #1004 on: April 21, 2009, 04:03:42 PM »
@All,

Check this out. If I haven't overlooked something then that's it. And, let me add, if that's it then @eisenficker2000 rulez!
This looks like a classic case of having the Animation Step and Integration Error too high.  In this case they are set at their defaults, but the model has features that are of a smaller scale.  So the allowable calculation error set by these parameters is large in proportion to the balls in the model.

I first erased the extraneous geometry out of frame to the left of the wheel shown when the file opens.  Then I changed the Integration Error from .01 down to .0001.  Doing so immediately pops up an error that one of the balls is overlapping the edge of a slot.  Fix the location of that ball and a second allarm for another ball overlap occurs.  Fix that one and a third pops up.  Fix this final overlap issue and the models is now okay to run.  Then changed the Animation Step from .05 to .001 and let it run.  I moves CCW a small amount, finds it's equilibrium point, and stops.

With the error allowed to be so high, there is always a few balls in collision with the slot walls.  I believe WM2D tries to work through these collisions by increasing the repulsive force between he two objects in an effort to have them separate on the next iteration.  This model cannot get out of the collision state and always has an extra repulsive force between balls and some slots.  This pushes the wheel around backwards.  Lowering the error allows for a better approximation of reality and no rotation.

Thanks,

M.