Electrical capacitors having low capacitance tolerances and method for the manufacture thereof

Claim 1

An electrical capacitor, comprising: a stack of at least two dielectric plies of plastic; regenerably thin metal coats on at least one side of said at least two dielectric plies; metal-free insulating strips provided on said at least two dielectric plies in alternation from ply to ply in proximity to different edge sides and at a distance therefrom; metal layers applied to said edge sides to contact said metal coats with opposite polarity from ply to ply; overlap of said metal coats being modified from a rated overlap of said metal coats in accordance with an equation C=εε o nL (u+Δu)/(d+Δd) to compensate for fluctuations from a prescribed rated thickness of said dielectric plies, where C is the capacitance of the capacitor, ε is the dielectric constant of the dielectric material used, ε o is the dielectric constant of a vacuum, n is the number of plies of the film capacitor situated on top of one another, L is the length of the film capacitor defined by a parting cut, u is the lateral rated overlap, Δu is the modification of the lateral rated overlap, d is the rated dielectric thickness and Δd is the fluctuation of the rated dielectric thickness.

Claim 7

A method of manufacturing an electrical capacitor formed by at least two dielectric bands having metal coats on at least one side the method comprising: capacitively measuring a thickness of at least one of said at least two bands provided with metal coats on at least one side before winding onto a capacitor winding; winding a capacitor winding with said bands onto a winding drum or winding spindle; and modifying lateral overlap of said bands in accordance with fluctuation of band thickness from a prescribed rated value.

Claim 8

A method of manufacturing an electrical capacitor formed by at least two dielectric bands having metal coats on at least one side the method comprising: capacitively measuring a thickness of at least one of said at least two bands provided with metal coats on at least one side before winding onto a capacitor winding; winding a capacitor winding with said bands onto a winding drum or winding spindle; and modifying lateral overlap of said bands in accordance with fluctuation of band thickness from a prescribed rated value.

Claim 16

A method of manufacturing an electrical capacitor formed of at least two dielectric bands having metal coats on at least one side the method comprising: winding a plurality of the dielectric plies of bands on top of one another; comparing thickness of said plies to a rated thickness; and compensating deviation from an anticipated rated capacitance due to differences in thickness by modifying lateral overlap of said plies to be wound from a rated overlap on until an ultimate thickness is reached.

Claim 17

A method of manufacturing an electrical capacitor formed of at least two dielectric bands having metal coats on at least one side the method comprising: winding a plurality of the dielectric plies of bands on top of one another; comparing thickness of said plies to a rated thickness; and compensating deviation from an anticipated rated capacitance due to differences in thickness by modifying lateral overlap of said plies to be wound from a rated overlap on until an ultimate thickness is reached.

Claim 25

A method of manufacturing an electrical capacitor, comprising: providing a dielectric band as a mother band having a width amounting to a multiple of a width required for individual capacitors; providing said dielectric band with metal strips proceeding in a longitudinal direction; providing metal-free strips of substantially identical width and having identical spacing from one another, said metal-free strips being located between said metal strips; dividing said dielectric band into individual bands at cutting lines, said cutting lines being spaced a slight distance from an edge of said metal-free strips; laterally displacing said cutting lines depending on a thickness of said band so that a width of an active metal coat is proportional to said band thickness; and winding capacitors with said individual bands.

Claim 26

A method of manufacturing an electrical capacitor, comprising: providing a dielectric band as a mother band having a width amounting to a multiple of a width required for individual capacitors; providing said dielectric band with metal strips proceeding in a longitudinal direction; providing metal-free strips of substantially identical width and having identical spacing from one another, said metal-free strips being located between said metal strips; dividing said dielectric band into individual bands at cutting lines, said cutting lines being spaced a slight distance from an edge of said metal-free strips; laterally displacing said cutting lines depending on a thickness of said band so that a width of an active metal coat is proportional to said band thickness; and winding capacitors with said individual bands.