Introduction Electrical coils and components have for some time been encapsulated or potted with thermosets for protection from operating environments and to provide electrical insulation and thermal dissipation.
With their good electrical properties, mould flow characteristics, and low cost, thermosets such as epoxies, phenolics, and thermoset polyesters were until recently virtually the only encapsulation resins used in coil / component encapsulation.
However, encapsulation materials are now shifting in the direction of thermoplastics.
This is occurring for reasons of:
- productivity and component integration;
- better physical properties of thermoplastics in thin sections compared with thermosets;
- extensive IEC 85 and UL 1446 Electrical Insulation Systems recognitions for thermoplastics for encapsulated motors, solenoids, and transformers;
- the virtual elimination of volatile organic compounds (VOCs) generated in thermoset potting or encapsulation