F6 posted this reply on another bench
https://www.overunityresearch.com/index.php?topic=4587.msg110319#msg110319I haven't heard that room temperature demagnetizes with the possibility of recovering energy at the same time, unless the ferromagnetic material was initially hotter than room temperature because it had just been magnetized.
If one studies the Neel equation in post #73 it tells you that ferromagnetic material consisting of single domain particles at room temperature will demagnetize exponentially with time, having a time constant that can be many years (permanent magnets) or fractions of a second (currently an unknown feature not used to any purpose). It should be clear to anyone skilled in electromagnetics that a decay of remanent magnetization in fractions of a second can induce voltage into a coil and drive current through a load, hence recovering some energy. Those same skilled people would likely accept that this one-shot energy pulse could occur at a hot temperature near the Curie point of the material. To then create a series of output pulses that yielded a useful average is clearly impracticable, the repetition frequency would be too low and the energy cost in heating and cooling would ensure overall efficiency close to zero. Whether the one-shot pulse input energy needed to magnetize is less than the one-shot output energy is a moot point not worth considering. Not surprisingly, also not considered is how near the Curie point would this impracticable system have to be. As F6 implies, the ferromagnetic material would have to be initially hotter than room temperature. And that begs the question, what is hot?
The Neel equation uses a thermal energy given by KT, where K is Boltzmann’s constant and T is temperature,
and here it is absolute temperature in degrees Kelvin. That answers our question, an ambient temperature of 20°C is 293°K hot.
Our ferromagnetic material is 293 degrees hot, and that is 29% of the way towards the Curie point of electrical steel. Now the possibility that a ferromagnetic material can have a demagnetization time constant of milliseconds at room temperature is not pie-in-the-sky nonsense, such a material can exist. With such a material we can have a continual series of one-shot electrical magnetizing pulses each followed by thermally driven demagnetizing that delivers an electrical energy output pulse, and the average output is useful, this is practicable. Note that although this is thermally driven, there are not two thermal baths, only the one. Perhaps this points to the thermal agitation that creates the field decay being linked to quantum uncertainty, and this system is linked to the active aether that Tesla called the wheelwork of nature.
The ratio of the two energy pulses is now no longer moot. We know how to assess the input pulse energy, but how do we assess the output energy? If we wish to use our electromagnetic knowledge involving inductance and current, what inductance value should we use? If our remanent field is close to saturation, we know that the inductance is very low, the material has lost its high permeability and will have a value close to 1. Also, we know that by Lenz’s law the output current will attempt to stop the demagnetizing thus holding the field close to this low inductance regime. Since this field decay is not driven electrically, it is quite possible that the output energy exceeds the magnetizing input energy where the high permeability, high inductance ensures that the remanent field is reached with very small input current and very little energy.
Why has this possibility not been considered before? The history of magnetic material development has followed various paths none of which has searched for fast remanent field decay. For permanent magnets and for magnetic recording the efforts have been in the opposite direction, retention of the field. For transformer cores the aims have been to extend frequency response and to minimise core loss, the latter leading to smaller remanent fields. For normal transformer operation the thermally driven decay time constant has been of no interest hence there is little evidence for this characteristic. Perhaps the difficulty in measuring this parameter in closed magnetic paths is another reason for the paucity of data. The ideal material for this new application is a high remanent field with a fast decay time-constant, and to date there has been no research into creating such material.
The superparamagnetic material obeying the Neel formula is an array of single domain particles. Some ferrites cores are made of such particles, the ferrite material is ground down to a fine dust where the grain size is a single domain. This material is put into a mould to create say a ring core, a toroidal current then aligns each grain dipole and the material is fired to produce a ring core with aligned domains that can flip to an alternative polarity if so desired. This creates highly anisotropic material that has desirable properties along the easy axis. But I guess no one has been interested in its remanent decay time constant.
Smudge