Hi,
I have been puzzled over those eccentric heat engine using nitinol wire.
The basic concept of this heat engine is that when you heat nitinol, this material wants to go back to its original form.
This will force the engine to rotate. How the nitinol engine works: https://youtu.be/oKmYqUSDch8
What if we replace heat with magnetism, and replace nitinol wire with iron pieces that is hinged on to the eccentric hub and the outer rim?
The idea is to create tension without using heat and nitinol wire.
Each iron piece on one side is pulled by the magnet, increasing tension between the rim and hub. Since the hub is eccentric, and the magnets wants to approach the magnet, the tension might force the engine to rotate. Attached a sketch of this idea.
The iron pieces actually don't approach the magnet, since the magnet is orientated parallell to the path of the iron pieces. Don't know if this is necessary.
The iron pieces is only pulling the hinges, and the only way the tension can be released is to move the iron pieces in the direction wher the gap between the hub and rim gets narrower. Just as in the nitinol engine - but opposite.
What do you think?
Br. Vidar
It is a possibility that the iron pieces (green) are being pulled slightly in reverse, and compensates for the tension that is forced the wheel to go forward.
I try now to find a way, using levers or something, that might prevent any magnetic reverse force to interact with the desired forward rotation.
I am surprised that no one have commented this topic yet ;D . If I have been unclear in my explanation of desired operation, please let me know ;)
Vidar
In this type of arrangement, the forces from the magnets can
cause the the device to briefly rotate, but only until all of the forces
come into balance. Then the device locks into that position, held
there by the opposing magnetic forces.
Yes Floor. That was pretty much what I was thinking too.
Quote from: Floor on April 13, 2022, 11:25:45 AM
In this type of arrangement, the forces from the magnets can
cause the the device to briefly rotate, but only until all of the forces
come into balance. Then the device locks into that position, held
there by the opposing magnetic forces.
I've decided to build it anyways, but I will not use separate steel pieces as the spokes will lean backwards and pull back on the direction that was supposed to go.
I have two 110mm diameter ring magnets, ferrite. I managed to split one of them in two equal halfs, and reversed one half, and glued both together with epoxy, into a two pole ring magnet.
This new ring magnet have now two sides with opposite magnetic fields, which will be the stationary magnet.
The other ring magnet with uniform magnetic field will be fixed to levers/spokes as sketched as black lines in the initial picture. What the two pole magnet will do is to attract one side and repel the other side of the other ring magnet. This will create a pushing force on the levers on one side, and pulling force on the other side. There will be zero cogging, and no resting position in the magnetic domain.
What I hope to achieve is ofcourse rotation. The force pushing on the spokes on one side might force the lever spokes to expand and seek the widest gap between the two wheels.
On the other side it will be a pulling force that force the lever spokes to contract and seek the narrow gap between the wheels.
Then the idea is to easily, with no input forces involved, manually turn the stator magnet 180 degrees, to change direction of rotation.
It must be something that prevents this from working. I just need to find out how.
At the moment I'm designing a 3D model that I will print on my 3D printer.
Vidar
Here is the magnets I will use in this experiment.
One side attracts ans the other side repels. It looks quite stable too
Gday
First of all, I love the design, It seems to me a unique design.
I am well versed in gravity engines. I feel the normal problems exist with your mag./gravity engine.
Although you feel like magnetism is actuating the "arms", it is gravity that has to make each piece of metal transverse the magnetic fluctuations. So your biggest problem becomes getting more from gravity than than you are taking. In my experience that never happens.
Good luck.
Quote from: Tarsier_79 on April 17, 2022, 05:15:01 AM
Gday
First of all, I love the design, It seems to me a unique design.
I am well versed in gravity engines. I feel the normal problems exist with your mag./gravity engine.
Although you feel like magnetism is actuating the "arms", it is gravity that has to make each piece of metal transverse the magnetic fluctuations. So your biggest problem becomes getting more from gravity than than you are taking. In my experience that never happens.
Good luck.
Thanks. This desgn has actually nothing to do with gravity. It is suppose to 'work' in any possible position. Even in zero gravity. Just like a skater moves forward just by position the skates a bit skewed outwards. As the legs spreads, there is forward motion.
In my design, the magnets are not doing any work per say, but the pushing and pulling forces on each sides is spreading or contracting the 'legs' to allow motion towards respectively wider or narrower path between the outer and inner rotor - wich has their hubs a bit offset from one another, just like the tension that occours in a heated nitinol wire in an eccentric nitinol heat engine.
I've already printed a few parts for this design.
Vidar
Ha ha.
I thought you were making something like a crosss between a rubber band type heat engine with nitinol spokes, using magnetism for over-balance. My mistake.
Are you just using PLA in your printer?
Good luck with your build.
Quote from: Tarsier_79 on April 17, 2022, 09:05:30 PM
Ha ha.
I thought you were making something like a crosss between a rubber band type heat engine with nitinol spokes, using magnetism for over-balance. My mistake.
Are you just using PLA in your printer?
Good luck with your build.
Oh gosh, that picture was terribly large ;D
It is polycarbonat I'm using. PLA is cheaper, and strong enough, but I haven't PLA right now :-)