Carlos, Conceptual, I have read about the Perendev motor and I have seen the video in YouTube. Its inventor alleges he can create energy from nothing and thus is a perpetual movement machine. This kind of machine has been proposed once and again in the last 150 years. For a good list of perpetual machines I strongly recommend this page:
Donald Simanek's pages - The Museum of Unworkable Devices
It's interesting how the same ideas has been put forward once and again, specially for flotating bellows, magnets around a wheel and unbalanced wheels.
Some examples of perpetual motion machines:
Magnets around magnets (Perendev style): the magnets at the center attract or repel the magnets around them, which creates an "unbalanced" wheel that has to move
Answer and discussion that explains why it doesn't work (try to work it for yourself!)
Bellows under water that a weight opens
Answer and discussion
The ICW generator: a flotation device that has enough buoyancy to lift a couple of balls
Discussion
You should check for yourselves the incredibly varied ideas: the reverse osmosis machine, the sling accelerator, the Simanek's Silly Slinky Device whose image is here and that works using a Slinky (TM) toy:
Now, there are some engines that work using magnets or corona discharge, the first one invented by Franklin, the last by Tesla and others. They use magnets to move a wheel, but require a power source. Tesla hoped to harness the power of ionization in atmosphere, but concluded it was not economically feasible.
Nonetheless, that hasn't discouraged inventors, who try to circumvent Boltzmann laws of entropy. Here you have another stumper:
This "Gyrogenerator", a gyroscope, rotates around it axis because the earth rotates around it.
The answer to any machine that claims over 100% efficiency is the equation in Boltzmann's grave: S = k * log W
My advice: when analyzing a perpetual motion machine, do not look at the forces, look for the "energy path".
For example, the right side of the Slinky machine weights twice what the left side does (force analysis). However, the energy required to push up every link of the Slinky in the left side is twice the energy required to pull down the links of the right side, because you have to push them up twice the height, so the machine is balanced and does not move.
Another example: the rotating earth machine has to be "decoupled" from Earth by making it turn like a gyroscope. Guess what: the amount of energy you need to decouple it, is the same energy you get back when it rotates back "against" the Earth, minus the friction losses.
