IEC 60401-1-2020 Terms and nomenclature for cores made of magnetically soft ferrites – Part 1: Terms used for physical irregularities and reference of dimensions (IEC 60401-1:2020).
This part of IEC 60401 provides a nomenclature of the most frequent surface, bulk and shape irregularities relevant to cores made of soft ferrites (magnetic oxides). Most irregularities are graphically exemplified as visual aids. A general recommendation is also given in Annex A for a consistent scheme for specifying the exact location of the irregularity, combining a general name for the location with more detailed qualifiers of the specified location. This document can also be useful as a terminology reference when preparing technical documentation, irregularity inspection specifications, etc. This document also presents a method for defining the designation nomenclature for the major physical attributes of soft ferrite core shapes. The purpose of this document is to facilitate uniform usage of dimensional characters by manufacturers, specifiers, and users when describing core dimensions on drawings, in tables, and on catalogue specification sheets.
2 Normative references There are no normative references in this document.
3 Terms and definitions For the purposes of this document, the terms and definitions given in 4.2, 4.3, 4.5 and Annex A apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at
• ISO Online browsing platform: available at
4 Physical irregularities
4.1 General overview Physical irregularities mean here the surface irregularities, bulk irregularities and shape irregularities. The irregularity here stands for inconsistency of the state or quality of the part’s surface, bulk or shape with its intended regularity. These irregularities are considered here in the macroscopic scale, i.e. within the range of linear dimensions of irregularities from one micrometre to tens of millimetres. There is a great variety of surface, bulk and shape irregularities degrading the quality of parts made of ferrites. Different types of these irregularities can often occur together and overlap one another.
Each type of irregularity is, in general, produced by one or more of the following: process variability in a manufacturing step, handling, grinding, packing or transportation. The extent of the quality degradation is dependent on the type, scale, and combination of irregularities being present as well as on their locations on the part. There are locations particularly sensitive to the degrading effect of the specific types of irregularities. The irregularities can in extreme cases have a detrimental or critical effect on magnetic, electric and mechanical performances of the part. Operations performed on the part, such as marking, winding, assembling and mounting, can also be adversely affected by the irregularities. An ongoing tendency to upgrade the overall quality of the parts results in more stringent restrictions being imposed on the quantity of irregularities in these parts. This brings about a need for a set of definitions, or nomenclature, which would be a primary basis for approaches to irregularities and their location issues. Therefore, this nomenclature is intended to be used as a uniform reference when formulating more detailed descriptions of irregularities at specified locations, requirements and procedures related to the inspection and assessment of irregularities. This nomenclature can also be useful with regard to methods and tools used for detection, recognition and classification of irregularities.IEC 60401-1 pdf download.