High-temperature heating wires use the principle of thermal effect of electric current to generate heat.
The thermal effect of current: When the current passes through the resistance, the current does work and consumes electrical energy, generating heat, this phenomenon is called the thermal effect of the current. Practice has proved that the heat generated by the passage of the current through the conductor is proportional to the square of the current, the resistance value of the conductor itself, and the time when the current passes. This is the conclusion reached by the British scientist Joule and the Russian scientist Lenz, known as Joule's law and Lenz's law.
The high-temperature heating wire must have a suitable resistivity to achieve the purpose of energizing and heating. If the resistivity is too large and too small, a very short or very long, thin or thick heating wire is required, so that it is difficult to manufacture and use the electric heater of large and small power; The melting point should be relatively high, and it will melt if it cannot be heated.
At high temperatures, the chemical stability should be relatively high, and it cannot be oxidized quickly and the life is short. At present, the commonly used are: nickel-chromium wire, iron-chromium wire, pure nickel wire, constantan wire, Cama wire, copper-nickel wire, stainless steel, neo-constantan, manganese copper, Mennell, etc. The power of 220V/5A resistance wire is 1100W.
Choice of heating wire material
Heating wire is iron-chromium-chromium high-resistance electrothermal alloy, which has the characteristics of high resistivity, small temperature coefficient of resistance and high service temperature. At high temperature, the heating wire has good corrosion resistance, especially suitable for use in atmospheres containing sulfur and sulfides, and the price is low, which is an ideal heating material in industrial electric furnaces, household appliances and far-infrared devices.
Electric heating means that after the current passes through the conductor, the current will generate a certain amount of heat and be transferred by the conductor. The heating wire itself is a metal conductor that emits heat and provides heat energy when energized.
