Homemade termomecanica of the two wires Bashny.Net

Installation (battery-powered of the two wires) uses the effect of the appearance of EMF in the circuits composed of different metals or semiconductors.

Take two of the electric conductor, which are made of different metals, and solder their ends. Now when heating one and cooling the other end of the circuit conductors of the thermocouples (thermocouples) electric current flows. The EMF generated will depend on the temperature difference, as well as from the selection of materials constituting the thermocouple. The efficiency of such converters does not exceed 5-6%.

The maximum temperature to which to heat the thermocouple, is determined by the melting point of the elements. For example, a pair of copper — constant can be heated to 350 degrees, steel — Constantan up to 315... 649 degrees — depending on the diameter of the wire, and a pair of chromel — alumel to 700... 1152 degrees. To increase efficiency, as you know, it is necessary to increase the temperature difference between the cold and hot junction. But in the selection of pairs must take into account the thermal conductivity of the materials.

It is better if the ratio between the average thermal conductivity and average electrical conductivity will be minimal.
When selecting materials it is convenient to use the table below.

It is better to choose those that are most removed in the column from each other. For example, steel (top), Constantan (below) will give good results, but copper and silver — inactive elements. A pair of antimony-bismuth best, but almost inaccessible to the Amateur. Although it gives the largest thermoelectric voltage is about 112 mV/deg. the materials are too specific and rare.



In addition, each material indicated in the table, has a negative potential in relation to all the others above. For example, in a pair of steel — steel constant will have the relative capacity plus, and the Constantan is the negative. The thermocouple chromel — alumel chromel is positive and the alumel the negative.





For the manufacture of batteries you will need two pieces of wire (steel and konstantinovoj) with a diameter of 1.3 mm, a length of 18 m each. Each end of the element strip and twist together, then weld. Items attached to asbestos-cement panels (Fig. 1). When testing for individual thermocouple should give a current of approximately 22 mA from the heat of a match and about 30 mA when heated with an alcohol burner. Under normal combustion of a spirit-lamp battery will give 1.5 V at 0.3 A tone (Fig 2).

Having made a set of these batteries and connecting them in parallel, you can get a constant electric current capacity sufficient for powering transistor radio and similar electrical appliances. It is only necessary to remember that the series circuit increases the internal resistance of the battery.





A set consisting of several batteries, you can use a kerosene lamp, metal chimney or other similar sources of heat.published

Source: www.mobipower.ru/