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25W single wire power transmission
Is it possible to transmit electrical energy over a distance along one wire? Is it necessary to wind huge coils and transformers for this? Is it difficult to configure such a device? In this note, we will not only unambiguously answer these questions, but also give a detailed diagram for repetition at home. Such experiments were carried out by Nikola Tesla, to which he dedicated several of his patents. We will repeat this device on a modern element base, and on our own we will need to solder only a few parts, all the rest of the filling is already produced by the industry in the form of ready-made modules.
Fig.1. Schematic diagram of a longitudinal wave transmitter
We tried to give a theoretical substantiation of single-wire energy transmission in this work . Such a device always consists of a longitudinal wave transmitter (here it is shown in Figure 1), a single-wire line itself, which can be a thin conductor, the receiver, which is shown in Figure 2, and a secluded container, which is a counterweight for it. We will talk about the latter a little later, but for now we will consider the operation of the transmitter.
The transmitter in Figure 1 looks very simple at first glance. The PS1 power supply supplies 24V to the circuit. The generator of square-wave pulses DG1 feeds them to the gate of the output switch VT1, which periodically connects the primary winding of the output high-voltage transformer TH1 to the power supply. On its secondary winding, quasi-sinusoidal high-voltage oscillations are formed, which enter the single-wire line through the X3 connector.
It is interesting that the capacitor C5 is not resonant, but serves to protect the transformer, and the entire circuit, when the load is disconnected in the receiver. The resonance itself depends on the capacitance of the single-wire line and the TH1 transformer goes to it automatically. Even if you change the capacitance C5, the resonant frequency will not change. Also, an interesting fact may be that the DG1 generator must drive the output switch at a frequency slightly below the resonant frequency; this achieves the best conditions for the efficiency of the device. From here, by the way, the use of an external generator follows, and the circuitry of self-excitation of the circuit is not used.
Capacitors C1 and C2 do two things here. They create artificial grounding and protect the circuit elements from possible sudden voltage surges, dumping them into the electrical network, in fact performing the function of a spark gap.
Fig.2. Longitudinal wave receiver
Fig.3. Wiring diagram for transmitter, transmission line, receiver and secluded container
A longitudinal wave from a single-wire line, through connector X4, enters the primary high-voltage winding of the TH2 receiving transformer, the secondary winding of which is connected to an active load - an EL1 incandescent lamp (Fig. 2). The solitary capacitance is connected to the X5 connector of this circuit and creates an electrostatic counterbalance for the entire circuit (Fig. 3).
In this circuit, a low-voltage mosfet transistor IRFP260 is well suited as an output switch VT1. Moreover, you can choose the best one from the same batch, which will give the highest efficiency. The transistor must be installed on a radiator.
High-voltage transformers TH1, TH2 are the most scarce part of this circuit. The best option is the following brand: TVS-110PTs15 , - this is a line scan transformer from a Soviet-made TV. It holds the load well and has an optimal ratio of turns between the primary and secondary windings. But you can pick up any other similar one.
List of other elements of the circuit:
The EL1 incandescent lamp can have a wattage from 25 to 40 watts. Also, LED lamps work here. The more powerful the lamp will be used, the larger the isolated capacity Cs should be (Fig. 3). For example, for a lamp power of 25 watts, a solitary capacity can be in the form of a torus made of a corrugated pipe with an outer diameter of 45 cm (Fig. 6).
In the schematic diagram, we have divided the transmitter device into four blocks (Fig. 1). They also fit into the device body (Fig. 4 on the right). The location of the blocks relative to each other is not important, with the exception of block 4, where the high-voltage transformer is located: it is desirable to carry it as far as possible from the rest of the circuit.
Fig.4. Receiver and transmitter without bottom cover
Fig.5. Receiver and transmitter assembly
Fig.6. Secluded container Cs
Figure 3 shows the connection diagram of the transmitter, transmission line, receiver and secluded container into a single structure.
On the DG1 generator, you must set the frequency to 49 kHz, and the duty cycle - 50%. With a communication line length of 4-5 meters, the resonant frequency of the entire system will be in the region of 55 kHz, but, as we remember, the operating frequency of the master oscillator must be set a little lower. This principle can be used to configure such a system with a different line length or with other types of high voltage transformers: first, the resonant frequency is looked for when the lamp lights up to its maximum, after which it must be reduced by about 10%.
Attention! The transmission line is under high voltage, so care must be taken to ensure safety and not to touch it.
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