Controlled magnetic permeability of the ferrites

2020-05-07

Controlled magnetic permeability of the ferrites. Known , which describes the dependence of the relative magnetic permeability μ on the magnetic field or current in the circuit .

But very little information about how this permeability depends on the electric field in the ferrite material. Meanwhile, this is a very important property, relatively low-cost method allows you to change the inductance of the coil using a core with such a ferrite. . Ferrite with controllable permeability can serve as a magnetic key in control circuits of magnetic flows, parametric element in generators and 0based on parametric of the second kind. In the following experiments we will present unknown method of such control, the inductance of which can change several times!. Unlike the design of the ferrites, a schematic diagram of the experiment is quite simple . GG0 generator produces short pulses, which are served on the ferrite core Fe . Him wound coil, the inductance of which will vary depending on the parameters of the pulses and from the voltage source U0. Measurement of inductance will be done on the connectors XS0-XS0. .

. Ferrite cores were used of two types: ferrite ring and "fairytopia sausage" . Connect to the ferrites at points and was made as follows: for the ferrite ring was fastened contacts in the form of copper strips placed equidistant from each other circumferentially, and the "ferretboy sausage" contacts were attached on two opposite ends. On top of these ferrites were wound coil in the classical way . Their parameters will be given below. Generator GG0 applies here . . Experience 0. Ferrite sausage. It consists of 0 rings initial permeability of 0 NM, the size 0*15*7, which are bonded together on the same axis. On this design the coil is wound with a primary inductance of 0 mH . Here, as in the following experience, number of turns and the inductance value does not matter, important is only the change. . Plug-in meter inductance to the coil . Set the supply voltage U0 110 V, and the pulse width generator GG0 — 0 NS. By adjusting the frequency GG0 reduce the value of inductance and record this value. I must say that such minima can be many, but they all work in a very narrow range of frequencies. In this case, the same minimum can vary according to frequency with other Zachariah pulse duration and voltage to power the circuit, from which we can immediately conclude that the presence of ferrite for each of their optimal values. Outside these values, the ferrite behaves as usual, without changing its permeability. .

. Waveforms found in some lows with this core are presented in . The probe of the oscilloscope is connected to terminals X0-X0 of the generator GG0 with a divider 0:10. The first minimum value of the inductance of coil L0 is decreased almost two times, the second — ten times. . It should be noted that in all these changes the inductance of the power source spent power of about 0 watts. . Experience 0. Ferrite ring. In fact, it consists of 0 rings initial permeability of 0 NM, the size 0*85*12 that are glued together. The ring was wound the coil in the usual way inductance which amounted to 0 µh. Here, as in the last experiment, the number of turns and the inductance value does not matter, important is only the change. . In this experiment, the supply voltage will make less — 0, since the resistance between the terminals of the ferrite are small, and our task is to detect the optimal values at which the inductance change is relatively cost-effective way. The pulse duration will exhibit — 0 NS. At lower values, in this experiment, the ferrite did not want to change its permeability. The other values shown in the waveform of the found minima . Note that all changes of inductance in this experiment, the power source spent power of about 0 watts. .

. As used herein, the generator allows you to set the number of pulses in a packet, which was done in the following experiment. The result, as expected, represented the mean value of inductance is changed . The power source is spent here, the power of about 0 watts. . Insights. There is an assumption that a sudden decrease in magnetic permeability in certain frequency areas due to the particular orientation of the domains of the ferrite involved in some sort of ferroresonance. As already noted, the minima of the magnetic permeability and, consequently, the inductance of the coil was observed over the whole frequency scale of the driving pulses. An approximate picture of their distribution, we demonstrated in figure . It should be noted that immediately after the minimum appears a small high, but it is sometimes subtle and easy to miss, as for example, in the case of a core in the form of "sausages". . . Option of change of inductance depends not only on the pulse duration but also on the supply voltage. Too little — no effect, while too much may damage surrounding devices, and is not efficient in terms of energy consumption. I.e., in addition to frequency and duration of pulses necessary to choose the optimal voltage to power the circuit. . In any case, in the here presented experiments, the cost of the change in magnetic permeability are small relative to capacities, which is able to pass through the ferrites. In addition, the magnetic field, which makes the circuit pulse current through the ferrite, does not affect the current flowing in the coil L0, because these fields are perpendicular to each other. Conversely, the magnetic field generated by the coil L0 does not affect the current from the generator GG0. This means that we are dealing with a parametric scheme . And if so, such a device opens a direct way to parametric generators of free energy. In future works, we consider some variants of such technical solutions. . Although in these experiments was represented by only two types of ferrite cores such parametric changes in magnetic permeability are suitable for almost any ferrite with a finite ohmic resistance. . . . .