As Dr. Donald E. Simanek, Emeritus Professor of Physics, Lock Haven University of Pennsylvania, explains, https://www.lhup.edu/~dsimanek/museum/peopl/people.htm
"all motions of the wheel and its parts are repeated exactly during each complete revolution. So if a weight moves to a larger radius once per cycle, it must also be pulled back to the original radius later during the cycle. The work done in changing the radius by a certain amount from large to small is equal and opposite to the work done in changing the radius by the same amount from small to large. We gain no net energy per cycle."
This is true and demonstrates why all the 'experts' refuse to accept Bessler's claims to have designed and built a working perpetual motion machine. But the description he gives above does not cover all possibilities. I know of at least two alternative concepts that will avoid his conclusion. In fairness to him I know he showed a number of historic designs which clearly did not work and perhaps he was only referring to them. The designs all depend on the use of gravity as an enabling medium, as do mine and many others - notice I did not say energy source!
I know (and have known and believed for at least 40 years!) that gravity does not provide the energy for a theoretical gravity wheel, but the falling weights do. It's a curious fact, this assertion that gravity is not an energy source, because we tap it every day in the form of falling weight clocks, falling water to generate electricity and possibly a hundred other ways we depend on upon its existence.
It isn't a source of energy, but if it isn't then what is it?. If, as I and many other here believe, Bessler used the falling weights to drive his wheel, they provided the energy to make it rotate, but without the force of gravity to make the weights fall, then the wheel wouldn't turn.
Current energy sources include solar, wind, water, geothermal, nuclear energy and of course coal, oil and natural gas. Some of these terms describe the source before conversion to usable energy. Our potential use of falling weights also uses gravity energy before conversion. Yet gravity is not a source of energy but the others listed above all are.
My personal opinion is that those who criticise the notion that the energy comes from gravity are being pedantic. Even though I knew that gravity isn't an energy source way back in the 1970s I still believe that because it causes objects of mass to fall, that action can be turned to advantage. It's like criticising the term 'petrol' or 'gas' or 'diesel' engine because it isn't the liquid fuel that supplies the energy, but rather the heat or explosive force that the fuel provides when it ignites. The fuel, like gravity is an enabler. One thing I'm sure of is that 'gravity wheel' or 'gravity engine' is how they will be referred to in the media, once they are verified as legitimate.
We know what we mean by these energy terms so when I say the gravity wheel taps the energy of gravity you know what I mean.
Any way be assured that Mr Simanek is right as far as he goes but he has not considered any possible work-arounds, and they hold the key. I look forward to the day he discovers the true Bessler's perpetual motion machine