Thermally Conductive Epoxy for Encapsulating Industrial Magnetics
Windings don't just carry current — under high load they generate real magnetic force, and that force turns into vibration and acoustic noise that fatigues insulation over time, which is exactly the problem potting compound is meant to solve in heavy-duty industrial drives. The Combined Threat: Heat, Vibration, and Voids In heavy-duty industrial drives, transformers, chokes, and inductors — collectively magnetics — carry the burden of power stability under significant stress. High currents generate substantial heat, and the components themselves produce magnetic forces that cause vibration and acoustic noise through magnetostriction. This continuous mechanical and thermal stress accelerates insulation breakdown over time and, left unaddressed, leads to component failure. For drive and power supply manufacturers, encapsulation with a high-performance potting material is the standard solution. Potting industrial magnetics demands an epoxy that excels in three areas at once. Void-free penetration is essential, since air pockets within the windings act as thermal insulators and points of electrical discharge that accelerate failure. Thermal dissipation has to efficiently conduct the ohmic heat generated by current flow away from the windings and core toward the housing. And structural damping requires the cured mass to be rigid and strong enough to lock the windings and core in place, mitigating the vibration and acoustic noise caused by magnetostriction and switching frequency effects. How Epo-Weld™ Meets Industrial Magnetics Requirements Incure's Epo-Weld™ thermally conductive epoxy is engineered for exactly this combination of flow characteristics, thermal performance, and mechanical rigidity. A working viscosity in the low thousands of centipoise penetrates deeply into tightly wound coil structures, eliminating the voids that would otherwise become both thermal hot spots and corona-discharge sites under sustained electrical load. Cured thermal conductivity in the 1.0–1.4 W/mK range moves heat from the windings and core toward the housing meaningfully faster than unfilled potting compound, directly supporting higher sustained current ratings for a given thermal budget. Mechanically, tensile strength in the low thousands of PSI combined with high flexural strength gives the cured epoxy the rigidity to lock windings and core in place against magnetostriction-driven vibration, reducing both mechanical fatigue risk and the acoustic noise that unpotted or poorly potted magnetics are known for. Dielectric strength above 80 V/mil provides insulation margin appropriate for industrial drive voltages, and a service temperature range extending from well below freezing to over 200°C accommodates sustained high-load operation without the compound softening or losing mechanical integrity. Application Notes for Void-Free Coil Potting Getting a genuinely void-free fill in a densely wound coil benefits from preheating the assembly slightly above ambient, which lowers resin viscosity further and improves penetration into microscopic gaps between turns. A slow pour from one side of the mold, rather than flooding the center, allows trapped air to escape ahead of the rising resin line. For particularly fine-gauge or multi-layer windings, a brief vacuum degas step meaningfully reduces void risk beyond what a gravity pour alone achieves. Email Us for guidance on pour technique for a specific winding geometry. CTE Mismatch in Potted Magnetics A potted transformer…