Application note
AN0020Contactor and Fuse Coordination in High-Voltage EV Applications
How to coordinate contactors with HV fuses using time-current curves so neither ruptures during a short circuit.
Summary
High-voltage hermetically sealed DC contactors and fuses are the primary safety pillars in EV powertrains, isolating high-energy battery packs during both normal operation and fault conditions. As EV architectures move from 400 V toward 800 V and 1,500 V systems, the coordination between these two components becomes a critical engineering challenge. This application note provides a technical framework for coordinating Rincon Power contactors with high-voltage fuses, outlining the physical limits of the switching components and defining the crossover point of their time-current curves (TCC). It also gives guidelines to prevent catastrophic failure modes such as contactor rupture or sustained arcing during short-circuit events.
