Jack80dev wrote: Madrik wrote: It is also known, more or less, when the working magnet will give it up and lose its properties.
Disclose this knowledge to me, please, for I do not have it.
Sit down, therefore, wanderer, in front of my hermitage, and learn the secret hidden from the eyes of the little ones, somewhere in the middle of a physics textbook for grade 7 of elementary school, where few look, and of those who do look, only a select few have the courage to penetrate the runes of magical patterns and discover the truth about the world.
The strongest artificial magnet (because the natural one is weaker) contains up to about 342 kJ/m3 of energy (there are slightly weaker ones - depends on the material and workmanship - maybe there are stronger experimental ones or something like that, let's assume some average at this level).
As you add time to this, you get the value of the power that can be extracted from a magnet, in watts. To spare your weary mind the unpleasantness of science, that would be about 0.026 W/s. Or 0.095 kWh.
A truly impressive value. In each m3
If you wanted to build a magnetic motor of 0.95kW, running for an hour, you would need 10 m3 of the world's strongest magnets.
Because a m3 is a million cm3, then in each cm3 of a magnet (I understand that you have already received the honor of learning the knowledge of calculating the volume of cuboidal solids), you have exactly 0.342 J of energy. Or 0.000000026 W/s
Because they naturally lose 1% of energy per year, the average magnet works about 100 years, but after about 50-odd it already loses a significant part of its properties. This is under natural conditions - so at some point the refrigerator magnet will fall off.
Unfortunately. This action can be accelerated, for example, before raising the temperature, which happens when the magnetic field of the magnet begins to do the work.
Already 40°C raises the rate of energy loss to 11%.
Beyond a certain temperature, 100% degradation of the magnet occurs and it completely loses its properties. For a neodymium magnet, it's about 90°C and we say bye bye.
And unfortunately, the lost energy can not be recovered other than by re-magnetization in an artificial magnetic field, thus by providing additional energy.
And what are magnets good at?
Maintaining a magnetic field hardly consumes their energy.
You can therefore use them, for example, to create low-resistance magnetic bearings or shock absorbers.
And truth be told, most so-called "magnetic motors" are actually rotating low-resistance structures that, once given speed, rotate for a very long time with little loss of speed (which gives the impression that it is the magnets that drive them), but any attempt to apply a load to such a structure and take away the mechanical energy, causes the whole structure to stop.
And this is not surprising if we know how little energy is in this system and how little is used of it per unit of time.
This is why we do not have "magnetic" motors, but "electromagnetic" motors, where the magnetic field allows the transfer of electrical energy into mechanical energy, and it is the electrical energy that is responsible for doing the work, not the magnetic field itself.
Do you feel a touch of the wisdom of the universe after I have revealed to you this secret knowledge, engraved with a stylus in the eternal tabletop of the classroom bench, with the magical runes of mathematics?
Yes or no, you have rested, pick up your backpack and go preach new wisdom to the world.
And when you meet someone who does not have this knowledge, as I do, feel obliged to share this knowledge.
