Wear-resistant thermal resistance working principle and principle structure

1. Working principle The principle of wear-resistant thermal resistance is based on the characteristic that the resistance value of the conductor or semiconductor changes with the change of temperature. Wear-resistant thermal resistance also has many advantages. It can also transmit electrical signals far away, with high sensitivity, strong stability, good interchangeability and accuracy, but it needs power excitation and cannot measure temperature changes instantaneously. Different conductors have different electron densities. Because their electron densities are different, a certain amount of electron diffusion occurs. When they reach a certain equilibrium, the potential formed by the contact potential depends on the material properties of the two different conductors and their contact. point temperature. 2. Principle structure The wear-resistant thermal resistance adopts a three-wire system to eliminate the measurement error caused by the resistance of the connecting wire. This is because the circuits used to measure RTDs are generally unbalanced bridges. The thermal resistance is used as a bridge arm resistance of the bridge, and its connecting wire (from the thermal resistance to the central control room) also becomes a part of the bridge arm resistance. This part of the resistance is unknown and changes with the ambient temperature, resulting in measurement errors. Using a three-wire system, one wire is connected to the power end of the bridge, and the other two are connected to the bridge arm where the thermal resistance is located and the bridge arm adjacent to it, which eliminates the measurement error caused by the wire line resistance. 3. Principle-related features 1. Small size, no air gap inside, thermal inertia, small measurement lag; 2. Good mechanical performance, vibration resistance, impact resistance; 3. Can be bent, easy to install 4. Long service life. 5. End-face thermal resistance The temperature-sensing element of the end-face thermal resistance is made of specially treated resistance wire, which is closely attached to the end face of the thermometer. Compared with the general axial thermal resistance, it can reflect the actual temperature of the measured end face more accurately and quickly, and is suitable for measuring the end face temperature of bearing bushes and other parts. 6. Explosion-proof thermal resistance The flame-proof thermal resistance through the special structure of the junction box, the explosive mixed gas inside its shell due to sparks or arcs and other effects of the open circuit repair of the resistance body must change the length of the resistance wire and affect the resistance value, as It is better to replace the new resistor body. If it is repaired by welding, it can only be used after it has passed the calibration after welding.