Ordinary sensors for inductive heating can be made long or short, but their electrical parameters need to be exactly the same, so that the right match can be maintained.

The copper tube of the sensor can be either wide or narrow, and what’s the relationship between them?

For example, the inductor of heating stainless steel bar with a diameter of 100 is designed with 500KW and 1000Hz copper tubes of different lengths and widths to ensure that the electrical parameters are exactly the same.

**Coil 1**

**Coil 2**

It can be seen that the electrical parameters of the two inductors with different sizes are basically the same through appropriate transformation. The difference is that the original 500KW power is added to the length of 480mm, while the changed 500KW power of the coil is added to the length of 960mm. The power density is reduced, but the heating temperature is the same.

1. The number of turns of the original coil x current =16*7223= 115,568,

After the change, the number of turns of the original coil x current =22*7223=158606,

According to the principle of induction heating, the bar of the induced current and coil current, that is to say, the increasing coil winding, bar induced current is increased, the power is increased, but according to the calculation, the power did not increase, why, because the spacing increases, the corresponding resistance becomes small, power remain unchanged.

2. The length of the original copper tube, 16×3.14d copper tube length, 22×3.14d copper tube length, through the same current, should be the length of the power loss is large, but the meter shows that the two kinds of sensors, the power loss is the same, why, take the two kinds of sensors copper tube current distribution for analysis,

It can be seen that the distribution of copper tube current changes from the center to the two sides after the spacing becomes larger, which is also due to the decrease of actual resistance, causing the length to increase, but the total loss does not increase.

**Coil 3**

**Coil 4**

It can be seen that the width of copper pipe decreases by one time, and there is no change in electrical parameters. The only change is the change in the cooling water speed of copper pipe. The reason is also the same as the above analysis. The current copper tube is not distributed only on the inner surface of the coil.

**Coil 5**

**Coil 6**

Conclusion: The effect of induction heating can be controlled as long as the change rule of electric parameters, the change of length and size of the inductor, and the change of copper tube size of the inductor are well mastered.