Mechanical properties: including elongation, rebound angle, softness and adhesion, scratch paint, tensile strength and other items.
(1) The elongation reflects the plastic denaturation of the material and is used to assess the ductility of the enameled wire.
(2) The springback angle and softness reflect the elastic deformation of the material, which is used to evaluate the softness of the enameled wire.
(3) The toughness of the paint film includes winding and stretching, that is, the allowable stretching deformation of the paint film without breaking when the conductor is stretched and deformed.
(4) The adhesion of the paint film includes sudden tearing and peeling, and mainly evaluates the adhesion of the paint film to the conductor.
(5) The scratch resistance test of the enameled wire paint film reflects the strength of the paint film against mechanical scratches.
Heat resistance performance: including thermal shock and softening breakdown test.
(1) The thermal shock of the enameled wire is the ability of the paint film of the enameled wire to withstand heat under the action of mechanical stress. Factors affecting thermal shock: paint, copper wire, enamelling process.
(2) The softening breakdown performance of the enameled wire is to measure the ability of the paint film of the enameled wire to withstand thermal deformation under the action of mechanical force, that is, the ability of the pressured paint film to plasticize and soften at high temperature. The heat softening and breakdown performance of enameled wire paint film depends on the molecular structure of the paint film and the force between molecular chains.
Electrical properties include: breakdown voltage, paint film continuity and DC resistance test.
(1) The breakdown voltage refers to the ability of the enameled wire paint film to withstand the voltage load. Main factors affecting breakdown voltage: paint film thickness; paint film roundness; curing degree; external impurities in the paint film.
(2) The paint film continuity test is also called the pinhole test, and its main influencing factors are: raw materials; operating process; equipment.
(3) DC resistance refers to the resistance value measured in unit length. Its main influencing factors: (1) degree of annealing; (2) enameled equipment.
Chemical resistance includes solvent resistance and direct solderability.
(1) Solvent resistance. Generally, the enameled wire has to go through the impregnation process after being wound into a coil. The solvent in the impregnation varnish has different degrees of swelling on the paint film, and it is even worse at higher temperatures. The chemical resistance of the enameled wire paint film is mainly determined by the characteristics of the paint film itself. Under certain conditions of the paint material, the enamelling process also has a certain impact on the solvent resistance of the enameled wire.
(2) The direct solderability of the enameled wire reflects the ability of the enameled wire to solder during the winding process without removing the paint film. The main factors affecting direct solderability are: the influence of technology; the influence of paint.