Working principle of the electric heating tube and wiring method Electric heating tube

Electric heating tube

1. Purpose:

Electric heating tubes are very common in daily production and life, such as electric rice cookers, electric kettles, electric frying pans, electric mattresses, etc. commonly used in households. The common ones we have are drying boxes, rice steaming carts, electric ovens, etc. The heating devices of these appliances are all-electric heating tubes. From the medium, it is divided into two categories: heating the air and heating the liquid. Their working principle is the same, but the heat dissipation method is different.

2. Working principle:

The working principle of the electric heating tube is actually very simple. It uses the thermal effect of the current acting on the resistor.

Thermal power formula: P=I^2R (power P is equal to the square of current I multiplied by resistance R)

The inside of the electric heater is a resistance wire, and then the inside is filled with insulating quartz sand and magnesium oxide powder. The lower end is filled with quartz sand, because the cost is low, and the higher end is filled with magnesium oxide powder. The cost of magnesium oxide powder is It's higher. It can be divided into low-temperature powder, medium-temperature powder, and high-temperature powder. The price of the electric heating tube will increase with the increase of the purity of the magnesium oxide powder. General applications do not need to be so high-end.

3. Working voltage level:

The working voltage level of the general electric heating tube is 380V/220V. There are electric heating tubes with other voltage levels on various occasions, which are rarely used.

4. Wiring method

The electric heating tube can be divided into single-phase and three-phase according to the power supply. It can be divided into single groups and multiple groups according to the form.

Single-phase wiring is very good because there are only two terminals, one zero and one fire, it's fine.

Three-phase is more troublesome. There are star connection and angle connection. There are six connection terminals. It is very troublesome to describe everyone in words and it is not easy to understand. It is the most intuitive way to express yourself with pictures：

One means 380V electric heating tube-connection method

Two means 220V electric heating tube-star connection

Three means 220V electric heating tube, connected to 220V incoming line (can be connected to 380V as shown in Figure 2)