This part of IEC 63093 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of PQ-cores and low-profile PQl-cores made of ferrite, and the locations of their terminal pins on a 2, 54 mm printed wiring grid in relation to the base outlines of the cores. It also gives guidance on allowable limits of surface irregularities applicable to PQ-cores in accordance with the relevant generic specification.
The selection of core sizes for this document is based on the philosophy of including those sizes which are industrial standards， either by inclusion in a national standard, or by broad-based use in industry.
This document is a specification useful in the negotiations between ferrite core manufacturers and customers about surface irregularities.
The general considerations that the design of this range of cores is based upon are given in Annex A.
