Wound film, Multilayer (PML), and Stacked film. Wound film includes polymers, paper and paper/plastic, with either metalized electrodes or discrete foil. A wound film Capacitor is just that, where two or more films/electrodes are spirally wound on a mandrel to a predetermined number of turns, length, or capacitance value.
Metalized Electrode Discrete Foil Electrode Hybrid electrode Metalized ElectrodeCapacitor or commonly know as Metalized Film Capacitor, consists of a thin layer of metal, typically aluminum, zinc, or an alloy of aluminum/zinc, which has been previously deposited onto the dielectric.
In other words, the operation performance of film capacitors is largely determined by the properties of polymer films, such as dielectric constant (ε r), dielectric loss (tan δ), breakdown strength (Eb) and electrical resistivity, glass transition temperature (Tg).
Since, in principle, a stacked-film capac-itor comprises a large number of independent capacitors in parallel, any contact weakness occur-ring can only affect individual capacitor elements, not extending to neighboring ones, and thus limiting damage to a minor loss of capacitance. Refer to chapter "EMI suppression capacitors" of this data book.
This paper is divided into two parts: first, the capacitor film manufacturing technology is briefly outlined, and then, a comprehensive review of a modern capacitor-grade polypropylene film is given. Capacitor-grade BOPP film is made of highly isotactic polypropylene. The molecular structure of PP with higher isotacticity is more regular.
A capacitor's ability to withstand vibration (e.g. as occurs in applications involving rotating machin-ery), is tested to IEC60068-2-6:2007. EPCOS offers film capacitors especially designed for operation under more severe vibration regimes, such as those found in automotive applications. Further information available upon re-quest.