How to Select Potting Compounds for Automotive Start-Stop Power Supplies? Recommended Grades for Inductors, Current Sensors and EMC Cores
Different components inside automotive start-stop power supplies have different potting requirements. SIPA 1850 (15#) can be selected for low-stress thermally conductive potting of inductors; PUR 1680 is available for evaluation on current sensors; EP 1788 is suitable for EMC magnetic core potting. Covering silicone, polyurethane and epoxy systems respectively, the three materials balance thermal conductivity, flexibility and structural support. Why Cannot a Single Potting Compound Be Used Uniformly for Start-Stop Power Supplies? Automotive start-stop power supplies contain: These components vary greatly in sensitivity to material hardness, mechanical stress and thermal conduction.For instance, current sensors demand precise control of mechanical stress; magnetic cores generally require stronger structural fixation; inductors need to achieve heat dissipation at the same time. Inductor Potting: SIPA 1850 (15#) SIPA 1850 (15#) is recommended for inductor potting. It is a 1:1 two-component thermally conductive silicone potting compound. As specified in the datasheet, it delivers Shore A 20 hardness, low stress and thermal conductivity of around 1.5 W/m·K. This solution fits inductors requiring a combination of:Thermal conduction + insulation + buffering + potting protection. Current Sensor Potting: PUR 1680 PUR 1680 is a 100:16 two-component thermally conductive polyurethane potting compound. According to datasheet, it features medium hardness and high elasticity, with thermal conductivity ranging from 0.8～1.2 W/m·K for current sensor encapsulation. Compared with high-hardness epoxy, elastic polyurethane helps buffer structural stress effectively. EMC Magnetic Core Potting: EP 1788 EP 1788 is a 100:15 two-component epoxy potting compound designated for EMC magnetic core potting. It boasts stable thermal cycling performance and thermal conductivity of approximately 0.7 W/m·K. It is ideal for magnetic components requiring robust mechanical fixation and integral encapsulation. Grade Comparison for Start-Stop Power Supplies Component Recommended Grade Selection Focus Inductor SIPA 1850 (15#) Low stress & thermal conduction Current Sensor PUR 1680 Elasticity, thermal conduction & stress…
