These capacitors have applications in propulsion and auxiliary inverters, together with lineside supply equipment.
Most designs use polypropylene as the base dielectric.
With the advantages of low dielectric loss and high breakdown stress, both aluminium foil and metallised electrode designs are utilised, depending on the application. Foil electrodes are often used for snubber applications, whilst metallised electrode construction is frequently used in filtering applications. Metallised dielectrics give the advantages of a self-healing capability, such that a momentary breakdown from an overvoltage is cleared and the capacitor continues to function normally. A disadvantage of large capacitors is the high energy that could be fed into a self-healing event, which could cause consequential damage. NCL uses segmented, fused metallised technology designed to obviate these problems before they occur, and produces capacitors with fuse patterns designed specifically for the application.