Five general knowledge of conductive materials in air compressor maintenance
1. What is the skin effect of conductor?
When the AC current passes through the conductor, the current distribution on the cross section of the conductor is not uniform, and the current density at the center of the conductor is the smallest. The closer the outer surface of the conductor is, the greater the density is. This phenomenon is called skin effect.
2. How to solve the problem of conductor skin effect?
When making wires, the single strand wires are not very thick, which is a way to solve the skin effect. In large-scale engineering and high-voltage engineering, rectangular, rhombic, slot and tube structures are often used for buses with high current;
High voltage transmission lines are made of aluminum strands, and UHV lines are made of split wires, which can effectively reduce the negative effects of skin effect.
3. How is the thermal effect of current generated?
In the existing general circuit, the connecting wire of the electrified part of the circuit is composed of copper wire or aluminum wire. At present, the windings of various generators, motors, transformers and electrical appliances are mostly made of various copper wires.
Because copper conductor and aluminum conductor have a certain resistance, when the current flows through the connecting wire or coil made of these materials, it will certainly consume part of the electric energy, which will inevitably generate heat, so that the temperature of the connecting wire and coil will rise.
4. How to reduce the thermal effect caused by current?
According to the principle of thermal effect, as long as the conductive material with resistance is used in the circuit, it is impossible to completely eliminate the thermal effect of current.
Therefore, in the air compressor engineering, the thermal effect caused by the current can only be minimized. There are three ways to reduce the thermal effect:
(1) . use conductive material with good conductivity (i.e. high conductivity) as conductor, i.e. reduce the resistance of conductor.
(2) . reduce the current flowing through the wire. By increasing the voltage level, the current in the loop can be reduced when the electric power transmitted is the same.
(3) . reduce the ambient temperature of conductor operation. Strengthen the cooling of the electrified conductor, such as cooling water to the inner part of the conductor.
5. What is the maximum allowable temperature of common conductive materials?
When the conductor is not in contact with organic insulating materials or oil, the maximum allowable heating temperature of copper conductor and its alloy is 300C, that of aluminum conductor and its alloy is 200, and that of steel conductor is 400C.