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Mutual induction bifilar coil at resonance of the first and second kind
Unusual from the point of view of classical electrodynamics, the results can be obtained if we compare the power transfer between the bifilar coils for a classic resonance and resonance of the second kind (RVR). Under certain conditions, such transfer can be carried out not only using a magnetic connection and vzaimosoedinenie, but with the help of wave processes. The experiments described here allow an unambiguous conclusion that there is a fundamental difference between classical resonance and RVR in the case of energy transfer between the coils. In the second case, one can find the optimal gap between them, wherein the transmitting coil does not "feel" the load, which is connected to the reception.
For the first experiment as transmitting and receiving coil, we will use two bifilar: L1 and L2, respectively. For the second experiment will take two receiving coils (L2.1 and L2.2) and place both ends of transmission. The distance between them (the gap) determines the parameter d, and the appearance of one of the coils shown in the following photo.
Scheme the first experiment is presented in figure 1. Left — the location of the coils right a connection diagram. In the experience involves two bifilar coils: L1 relay, the L2 reception. Between the coils are made the air gap, the length of which may vary. Also, changing the resistance of the active load Rn, the voltage at which we define the transmission capacity and mutual induction.
Fig.1. Location bifilar coils and wiring diagram for the first experiment
GG1 generator generates rectangular pulses at the transmitting coil L1, which is configured to resonate (classic or RVR) together with capacitor C1, whose capacity in this experiment was made 33нФ. The fill factor of these pulses is 50%, and the frequency is as follows: for a classical resonance — by the formula of Thompson [1], the PAP — according to the formula (1.7).

The oscillator circuit GG1 is possible to take here, or you can apply any other material with similar characteristics. It should be noted that as a key transistor need to choose a MOSFET with a small on-resistance and maximum voltage closed — not less than 500V. Optimal 47N60. It is also possible that parallel to its drain-source will need to install a capacitor 400-1000пФ to minimize the self-excitation scheme.

EMF reception coil L2 is supplied to the diode bridge VD1 is smoothed by the capacitor Cn and is supplied to the resistance Rn, which we will measure the voltage Un. Below is a table of values for this experiment, which looks at the following fields:
  • — Kind of resonance: I — resonance of the rst kind (classical), II — RVR;
  • f, kHz — pulse frequency generator GG1 in kilohertz;
  • PGG1 a power consumption of the generator GG1 in watts;
  • Rn — the resistance Rn in Kromah;
  • Un — the voltage in volts on Rn.

The distance between the coils — 0mm

Rod f, kHz PGG1, W Rn, room Un In
I 123 5 10 120
I 123 15.7 1 106
II 30 5 10 124
II 30 10.1 1 80
The distance between the coils — 10mm
I 123 5 10 88
I 123 10.6 1 75
II 30 5 10 87
II 30 6.1 1 73
The distance between the coils — 20mm
I 123 5 10 66
I 123 7.7 1 53
II 30 5 10 62
II 30 4.8 1 36
In the first table, we have not seen anything unusual except for the fact that the transmitting coil less responsive to the load in the case of the RVV, but at the same time and power on it also less. You should pay attention to the second table that contains data when a gap of 10mm. It is already obvious difference in the reaction of the primary load change on the secondary: the classical resonance the load is changed 10 times, and power consumption GG1 changes almost in 2 times; in RVR — the load is changing 10 times, and power consumption GG1 is changed by only 22%. The power dissipated in Rn are almost the same! The third table, in RVR, a decrease in load resistance leads to a reduction in power consumption GG1 that can not be explained by the classic, truth and power on Rn also falls.
In the second experiment the author has arranged two receiving coils at both sides of the transmission. This is shown in figure 2. There is also presented and the scheme of their connection.
Fig.2. Location bifilar coils and wiring diagram for the second experiment
In such connection of the coils the author has failed to achieve any interesting results, but the trend of reducing the impact load of the receiving coil to the transmitting, with RVR, it also preserved.
The influence of the load of the receiving coil to the transmitting in the case of classical resonance is fully consistent with the mathematical model of electrical engineering. Reduce this load always leads to an increase in power consumption of the reference generator.
In the case of RVR the same clear correlations are not observed. You can find the optimal value of the gap between the transmitting and receiving coils, in which the load change will not affect the power of the oscillator. The author makes the assumption that in this case, the energy between the coils is transmitted not only by means of mutual magnetic flux linkage, but the process also involved the wave transmission. Therefore, when a certain gap is reflected waves from the receive coil with partial recovery.
To build optimum energy transfer between the coils, apparently required not only the selection of the optimal gap, but the design of the coil.
The materials used
  1. Wikipedia. The Formula Of Thomson
  2. Wikipedia. The duty cycle