Enameled Wire requires a uniform, smooth paint film and complete covering (fewer pinholes). Wire diameter and paint film thickness shall conform to national standards. The performance of enameled wire is determined by the paint film and generally includes the following items:
1. Mechanical properties. The paint film shall be scratch-resistant, elastic, with appropriate softness and elongation to ensure that it can withstand friction, bending, stretching and compression without damage during winding, embedding, stretching, shaping, etc.
2. Electrical performance. The main reason is that the breakdown voltage of the paint film is high. For enameled wires used in high frequency and high voltage motor windings, the loss tangent of the paint film is required to be small. For enameled wire with diameter less than 0.5, pinhole number is a very important index to evaluate its electrical performance. Many motor manufacturers are equipped with paint film continuity tester in the incoming inspection of electromagnetic wires to check the number of pinholes.
3. Thermal performance. Including softening and breakdown, thermal ageing and thermal shock properties of the paint film. Softening breakdown performance indicates the ability of the paint film to resist heat deformation under a certain pressure. Thermal ageing performance reflects the ability of the paint film to retain certain elasticity after a short period of thermal action. Thermal shock performance reflects the ability of the paint film to withstand thermal shock (quenching and heating) without cracking during baking, dipping or overload operation.
4. Chemical properties. Indicates the ability of the paint film to withstand corrosion by chemicals such as acid, alkali, salt fog, organic solvent or refrigerant.