The capacity accuracy of metallized polypropylene film capacitors is mainly affected by the thickness deviation of the film.It is not realistic to sort the film by thickness measurement.The winding number is corrected by detecting the element capacity after winding.However

the flat element after winding is loose and capacity measurement requires the element to be flattened and pressed

which is complicated in achieving and the efficiency is low.In this paper

a kind of method to adjust winding number by way of detecting element dimension can reduce the capacity deviation by thickness deviation.The method is simple and convenient in operation and has high efficiency.