Machines that can do work forever without consuming energy violate the law of conservation of energy, so they are called "perpetual motion machines of the first kind". In the absence of temperature difference, a machine that constantly absorbs heat from sea water or air in nature and converts it into mechanical energy violates the second law of thermodynamics, so it is called "the second kind of perpetual motion machine"
Perpetual machine refers to an engine that violates the basic laws of thermodynamics and never stops moving. Some people think perpetual motion machine is not appropriate. They said, "Once the flywheel starts to move, it can continue to move permanently without friction and resistance. Although this is not easy to achieve in practice, it is reasonable in reason and can be regarded as a practical limit. " They also believe: "The so-called perpetual motion machine does not mean this situation, not trying to maintain eternal motion, but expecting to continuously obtain useful power without external energy supply, that is, without consuming any fuel and power." In fact, this kind of worry is completely unnecessary, because the transformation of energy is directional.
Yes, no matter what movement in nature will produce heat, which will spread around and become useless energy. Any running machine will stop unless energy is provided. If this perpetual motion machine can really be made, then we can get infinite power out of nothing without using any natural energy. When people haven't mastered the basic laws of nature, this idea has tempted many people with outstanding creative talents, who have devoted a lot of wisdom and labor to pursue the realization of this dream. However, the perpetual motion machine has not been invented, never really made, and no design scheme of perpetual motion machine can stand the test of science. But friction resistance can be overcome by magnetic force, and air resistance can be overcome without weightlessness in vacuum.
Many people in history want to design a machine that does not consume any energy, but can continue to do work outside. This kind of machine is called perpetual motion machine. Historically, people have put forward many production schemes of perpetual motion machines. Although people made many attempts and efforts, the perpetual motion machine failed without exception. People call this kind of machine that does not consume energy the first kind of perpetual motion machine. The discovery of the law of conservation of energy makes people further realize that any machine can only convert energy from one form to another, and can't make energy out of nothing, so it is impossible to make the first perpetual motion machine.
Can you make a heat engine to transform different forms into each other completely without damage? This kind of heat engine has no condenser, only a single heat source, and all the heat it absorbs from this single heat source can be used to do work without causing other changes. Can't! People call this imaginary heat engine the second perpetual motion machine. Although it does not violate the law of conservation of energy, it cannot be realized because the transformation of mechanical energy and internal energy is directional.
So perpetual motion machine does not exist.
As for many fuel generators, they exist. With the great progress of science and technology and people's understanding of the environment, a series of clean energy sources have been developed and utilized by people, such as hydroelectric generating sets and wind generating sets.
I hope it will be helpful to you and I hope it will be adopted.