Robinhood46 wrote: ↑Tue Apr 02, 2024 2:38 pm
Fixed pulleys create no advantage whatsoever and are only useful for changing the direction of the actions involved.
There is something about pulleys that has been missed.
I am working through the Bessler Kinetic engraving examples.
Hopefully I will know more as the last example is a pulley.
Regards
[MP] Mobiles that perpetuate - external energy allowed
RH46: "Pulleys only create a ratio advantage if the pulley itself moves.
Adding pulleys that are fixed, increases the length of the rope needed to go round all the additional pulleys, but doesn't increase the distance the rope travels to cause the lifting." Yes, me bad, brain fart.
That said a diameter change in pulley size does make a mechanical advantage.
In a pulley system, the size of the pulleys can significantly affect the mechanical advantage and the speed of the load movement1234.
If the first pulley (the one attached to the load) is smaller in diameter and the second pulley (the one attached to the roof) is larger, the system will behave as follows:
Mechanical Advantage: The mechanical advantage of the system would increase. A larger pulley diameter results in a greater mechanical advantage, while a smaller pulley diameter results in a smaller mechanical advantage3. This allows for flexibility in the system, depending on the specific requirements of the application3.
Speed: A larger pulley diameter results in decreased RPM, whereas a smaller diameter increases RPM, showcasing an inverse relationship between pulley size and rotational speed4.
Force: The force transmitted to the driven pulley is inversely proportional to the speed. So, if the driven pulley is rotating faster (because the driving pulley is larger), the force it receives will be less. Conversely, if the driven pulley is rotating slower (because the driving pulley is smaller), it will receive more force24.
This setup could potentially provide a mechanical advantage, making it easier to lift the load. However, the exact setup of the pulley system would determine its effectiveness and sensitivity to movement1234. I hope this helps! 😊
Something doesn't sound right to me Daxwc.
Where does the text come from? Is it a discussion with ChatGPT, or from somewhere else?
I might be wrong, because you are making me doubt my reasoning, but the only way the advantage expressed in the text could be right, is if the rotation of the pulleys has an effect on the lifting. As in a rack and pinion, or another pulley of a different diameter doing the lifting, in which case the pulleys work in the manner of gears.
The diameter of a pulley will not affect the ratio if it is simply a rope passing through pulleys. The only affect to lifting is the resistance of the bearings due to the different speeds of rotation, the increased resistance with the air, due to increased speed and the forcing of the rope, string, chain, belt, or whatever, to bend more or less depending on the curve of the perimeter.
The different lengths, between the distance the effort end is pulled, and the distance the load end moves, is the only cause of a "ratio" of the effort.
I hope i make sense, and i hope someone can confirm or correct me if I'm wrong.
. If the first pulley (the one attached to the load) is smaller in diameter and the second pulley (the one attached to the roof) is larger, the system will behave as follows:
The load pulley in the pic is the roof pulley. Is the MA is going to increase or decrease if the diameters are switched ( larger on floor and smaller on roof)? Better radio the copilot, we might have some turbulence ahead.
So in the pic the driving pulley/axle is 8” diameter. The driven pulley is maybe 1/2 to 2/3 that; 4-6”.
The ma for that is 1/ [1/2] to 1/[2/3].
2 to 1.5 ish MA.
Ecc1: The load pulley in the pic is the roof pulley. Is the MA is going to increase or decrease if the diameters are switched ( larger on floor and smaller on roof)? Better radio the copilot, we might have some turbulence ahead.
That's correct. Copilot didn't know the setup. I gave it the wrong setup before I just looked at the picture.
Copilot: This setup could potentially provide a mechanical disadvantage, making it harder to lift the load. However, the exact setup of the pulley system would determine its effectiveness and sensitivity to movement
.
But they are different sizes which does affect the mechanical advantage.
Last edited by daxwc on Tue Apr 02, 2024 8:08 pm, edited 2 times in total.
Pulleys are gears without teeth if that’s what you mean.
The speed is affected, but there is either a MA gain or loss.
Good catch Dax if B. had an even bigger difference than the drawing indicates it could be that’s what what’s his name was referring to when he complained about the 5x pulley reduction.
Sam you beat me to it. If the rope at the axle moves up 6 inch's the box outside the window would move 6 inch's.
The only advantage I see is the wheel is attached to the floor so for stability it makes sense to pull up. If you look at the pulley's they end up with the rope on half their circumference this means better grip so less slippage and heat.
A short description here for this is that if a loop grinds into itself it can instead pull a spring on a gear that would pull the wheel mechanism a little harder if all of the items are moving in the same direction. Can doing this create Over Unity because of manipulating the gear sizes at the pulleys? The driving force is pulling a weight down by a pulley outside of the wheel mechanism but the over unity device would be the gears attached to the pulleys grinding into each other with various gear levers and speeds. I concluded that it might be possible in my drawing here that if the gear driving gear loop the grinds back into the wheel mechanism has a small gear attached to its larger pulley oriented gear that as long as the final driven gear in the center of the mechanism indicated by colors in this drawing is moving faster than the wheel that that spring could be turned with over unity MA.
"It's not the size of the dog in the fight, it's the size of the fight in the dog." - Mark Twain
