Why Thermal Conductivity Alone Is Not Enough for Transformer Potting Compounds: Winding Gaps Are Narrow — First Verify Whether the Material Can Flow In

Material selection for transformers and control power supply potting should not rely solely on thermal conductivity comparison. When there are numerous narrow gaps between windings, magnetic cores, pins and PCBs, the priority is whether the material can reliably penetrate these zones and form continuous insulation protection. Even an impressively rated thermal conductivity cannot compensate for internal voids. The interior of a transformer or control power supply is not a simple empty cavity. It typically accommodates windings, magnetic cores, bobbins, lead pins, PCBs and electronic components. The potting compound must flow through many narrow slits, corners and coil gaps. The first question to answer is not “What is its thermal conductivity?” It is: Can the adhesive reach the areas requiring protection? Why Flowability Is Critical for Transformer Potting Potting resin has to navigate intricate internal structures. Insufficient flowability creates this common defect: the surface appears fully filled, while unfilled voids remain trapped inside. Hotspots such as winding roots, the bottom of bobbins, pin surroundings and areas next to magnetic cores cannot be reliably checked only by observing the liquid level. In short: A complete top surface does not guarantee full internal potting. Why Lower Viscosity Is Not Always Better Low viscosity helps penetration into tight gaps, yet transformer potting cannot be judged by viscosity alone. Other key parameters include: Working life, settling stability, dispensing speed, curing profile and final mechanical properties. Blindly chasing ultra-low viscosity without considering mass-production processes may lead to uncontrolled resin run-off, uneven filler distribution and mismatched curing tact time. The proper selection principle: build a viable production process window on the premise of consistent structural filling. Why PUR 1627 Is Worth Evaluating for Complex Transformer Potting ELAPLUS PUR 1627 is a two-component solvent-free thermally conductive polyurethane potting compound, curable at ambient temperature or with heat. Mixed viscosity:…