Metalized AC capacitor processing

What are armature and metallized film capacitors?

Usually, armature capacitors are used for very high-current applications, while metallized film capacitors are used for low-current applications. Among these different film capacitors, supercapacitors should also be mentioned.

Do metallized film capacitors decrease performance with time?

Zn–Al metallized film capacitors in two different production stages were investigated to explain the decrease of capacitors performance with time. Unsealed and sealed capacitors with different aluminium content in metallization layer were investigated.

How is a metallized film capacitor made?

The first step in building a metallized film capacitor is physical vapor deposition under vacuum of a very thin layer (10 to 100 nm) of metal, such as aluminum, zinc or zinc–aluminum, on one side (evaporated to the surface) of a roll of polymer film . Sometimes, small amounts of other alloy metals are added to prevent corrosion.

What are the different types of metallized capacitor designs?

There are five main types of metallized capacitor designs, namely the dry metallized film design (Figure 1), liquid-impregnated–gas-impregnated metallized film design, cellulosic paper design, liquid-impregnated metallized polymer film design (mixed or all-film dielectric) and stacked metallized film design (Figure 3).

What is a stacked film metallized capacitor?

Stacked-film metallized capacitors consist of a stack of elementary capacitors connected in parallel . This particular assembly is suitable for applications requiring good compaction.

How metallized polymer film is used to seal a capacitor?

The metallized polymer film is then rolled and sealed into a casing whereby the sealing is supposed to remain tight over the entire lifetime of the capacitor. The capacitors perform well under usual conditions. However, in the course of time, the capacitors gradually lose their capacitance , , , , , , , .