Magnetic flux control idea

[Low-Q]

Finally a water proof bellow
I also cut the rods in two 5cm lengths.


Vidar

[tinman]

@Carrol
The motor used on the buoyancy wheel might suffer from the difference in efficiency. This can be adjusted on regular DC-motors by turning the commetators a little bit one way or the other, so the timing on the rotating electromagnets is equal in both directions.
The reason why his device got more volume on one side than the other, is because of the angle between the wheels. This angle also increase the surface area in front of each tube which will cause greater force in front of the tube than behind them. This counterforce is caused by the same angle that makes greater volume on the wide side than the narrow side. So these two forces adds up to zero.
Btw, even if steel rods doesn't float on water, he could likely used steel rods instead of hallow tubes.
The difference in buoyancy is the same

My ferrofluid is very slippery. It is some sort of silicone oil with magnetite powder in it.




@Brad
I can absolutely agree with you. Ferrofluid becomes a magnet. Strongest closest to the PM, but it also increase the pressure in the fluid which will make the steel rods more bouyant. Therfor harder for the steel rods to displace the fluid when they enter this area of higher compression. So what the magnetic field is attracting, the increased pressure will counterforce. So I don't think the attraction at the bottom is the main obstacle, but maybe it is.
However, something must account for conservation of energy. Cannot disagree on this.
I need to say that this is just a hobby. Much of my hobbies is creating problems at will, and then try to solve them - a troublemaker that cleans up after himself


Vidar

It is great to watch you carry this out to the end.
Looking forward to the outcome.

Remember,the conservation of energy only applies to a closed system.


Brad

[Magluvin]

Just remembering some things Ive seen with ferro fluid. Have you experienced ferro fluid while in proximity to a magnet? I believe it hardens up. Like in some computer controlled shock absorbers they use field coils to control the ferro fluid to control the shock absorbing feature. So as I see the wheel will need to squeeze the fluid to keep the weight of it more on one side of the wheel. If you havnt tested the fluid first(if you did I must have missed that part), Id give that a go first. With water and gravity you wouldnt have that hardening issue and the water probably squishes around better with less resistance. Nice work.

Mags

[Low-Q]

@Brad
Thanks Brad! This is a closed system, so conservation of energy is absolutely the law. Besides that, having the opportunity to print my own parts, cheap and flexible in the matter of shapes or material, is just great.


@Mags
Yes, you're right about the hardless. However, hardness is not the right term to use, because the fluid does not got denser - fluid is virtually incompressible, but the pressure in it increase when you approach a magnet.
I made a video this morning that demonstrates exactly that.
I used the cap for the ferrofluid box. Filled it with fluid, and tested two things:
One non-magnetic rod, and one magnetic rod that I just stirred back and forth.

My ferrofluid have too much oil in it, so it doesn't make these spikes you see on good ferrofluid close to a magnet.
The non-magnetic rod will not enter the fluid, because the pressure makes the rod too buoyant.
However, when I used the magnetic rod, it snapped right into the pond. Then I compared the magnetic attraction with a magnet without ferrofluid.
It is clearly less attractive inside the ferrofluid, but enough to overcome the buoyant effect.

Maybe a perfectly mixed ferrofluid, which is more magnetic, will balance the buoyant effect with attraction, so the steel rod doesn't "know" it is entering anything.
I think, however that would not make any difference for the experiments final outcome. But I just bought 400g magnetite powder so I can mix inn more magnetite into the fluid.
Estimated delivery is dec. 19th according to Ebay.

Here is the video of the ferrofluid vs magnetic, and non-magnetic steel rods:
https://youtu.be/mNQjKTvsb0k


Vidar

[Low-Q]

After lot of mess, I have filled it up completely with ferrofluid. The gaskets keeps tight, and there is no leak.
When I try to squeeze the bellow, it is a relatively great friction that release suddenly. After that, the rods slides quite easy. But the rods will get temporary stuck at the very widest side and the very narrow side, each time the gaskets in the two wheels change direction along the rods. Also, it is different friction on each side, so the rods will be pushed out one way or the other while the wheels turn. However, I need only 60° rotation to see what is happening, because it is 6 rods.
Next is to print out a structure that holds the two shafts, one for each outer wheels/discs, so they get locked in an angle of approx +/- 15° in the horizontal plane.
I will post pictures later.


Vidar