# Can we use counter-rotating rings to generate power on space

## Main Question or Discussion Point

I was reading a post by spongebob_79 about using counter-rotating rings to generate power and I had a thought. What is the general opinion of using counter-rotating rings mounted to 2 facing sides of a structure and simpily inducing opposite spins on the structures to generate power? Obviously good mechanical designs would need to be in play for it to work correctly and an amount of orbital construction would be needed as well. But, if it could be designed simply, cost effective, and modular then should not it be feasible?

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Bandersnatch
Energy extraction slows down the spin. Inducing spin costs energy. Energy losses in-between mean that you're putting more energy in than you're getting out of it.

phinds
Gold Member
2019 Award
I was reading a post by spongebob_79 about using counter-rotating rings to generate power and I had a thought. What is the general opinion of using counter-rotating rings mounted to 2 facing sides of a structure and simpily inducing opposite spins on the structures to generate power? Obviously good mechanical designs would need to be in play for it to work correctly and an amount of orbital construction would be needed as well. But, if it could be designed simply, cost effective, and modular then should not it be feasible?
Of course it's feasible if you don't mind spending extra money on totally wasted energy (as Bandersnatch pointed out) used to create the energy that you are "saving" that you could have just created directly.

I am led to believe the thief you mean is friction? What if the surfaces do not touch and the energy is produced by magnetic induction?

Bandersnatch
No. Friction is the cause of mechanical losses.
The mere fact that you're extracting energy slows down the spin - i.e. making the electrons move in a wire requires energy.

phinds
Gold Member
2019 Award
I am led to believe the thief you mean is friction? What if the surfaces do not touch and the energy is produced by magnetic induction?
There is no such thing as a 100% efficient motor or generator. So,

fuel -> motor -> spin -> generator -> electricity

has losses at every stage

So does

fuel -> generator -> electricity

but it has fewer stages in which to incur losses.

Ok. I understand. I am going to have to do some more research on the input costs v. output results. It just seems to me that in an orbital environment, the input energy to induce and maintain the spin would be less than the output gained in power production of the generator...strange.

phinds
Gold Member
2019 Award
Ok. I understand. I am going to have to do some more research on the input costs v. output results. It just seems to me that in an orbital environment, the input energy to induce and maintain the spin would be less than the output gained in power production of the generator...strange.
You are now talking about a perpetual motion machine ... free energy. It doesn't work and discussion of this crackpot idea are banned on this forum. I understand that you "get" that it doesn't work, I'm just letting you know.

berkeman
Mentor
Ok. I understand. I am going to have to do some more research on the input costs v. output results. It just seems to me that in an orbital environment, the input energy to induce and maintain the spin would be less than the output gained in power production of the generator...strange.
Welcome to the PF.

Over-unity mechanisms (and perpetual motion machines) are on the Forbidden Topics list in the PF Rules (see Info at the top of the page). We do not discuss them because they are a waste of time to discuss. Please see the links below in the quote from the Rules -- they should help you to understand the issues better.

Forbidden Topics -- Pseudoscience, such as (but not limited to):

Perpetual motion and "free energy" discussions
http://wiki.4hv.org/index.php/Free_Energy_Debunking
http://en.wikipedia.org/wiki/Perpetual_motion
http://www.skepdic.com/freeenergy.html
http://www.skepdic.com/perpetual.html