IEC 60938-2:2021 pdf download – Fixed inductors for electromagnetic interference suppression – Part 2: Sectional specification on power line chokes.
4 General requirements 4.1 General Units, graphical symbols, letter symbols and terminology shall be taken from the following publications whenever possible: – IEC 60027 (all parts), – IEC 60050 (all parts), – IEC 6061 7, – ISO 80000-6. When further items are required, they shall be derived in accordance with the principles of the documents listed above. 4.2 Preferred values of ratings and characteristics 4.2.1 Climatic categories Electromagnetic interference suppression inductors covered by this specification are classified into climatic categories according to the general rules given in IEC 60068-1 . The lower and upper category temperatures and the duration of the damp heat, steady state test shall be selected from the following: Lower category temperature: −65 °C, −55 °C, −40 °C, −25 °C and −1 0 °C. Upper category temperature: +85 °C, +1 00 °C, +1 25 °C and +1 55 °C. Duration of the damp heat, steady state test: 21 days and 56 days. The severities for the cold and dry heat tests are the lower and upper category temperatures respectively. 4.2.2 Nominal inductance and tolerance Preferred values of nominal inductance are values chosen from the E6 series of preferred values given in IEC 60063. The preferred tolerances on inductance are as follows: ±30 %; −30 % / +50 % 4.2.3 Rated voltage U R Preferred values for rated voltages are: • for AC inductors: 50 V, 1 25 V, 250 V, 300 V, 400 V, 440 V, 480 V, 600 V, 760 V, 800 V and 1 000 V. • for DC inductors: 60 V, 1 60 V, 250 V, 500 V, 1 000 V and 1 500 V. Electromagnetic interference suppression inductors are normally chosen to have their rated voltage equal to or greater than the nominal voltage of the supply system to which they are to be connected. It should, however, be borne in mind that the voltage of the system may rise up to 1 0 % above the nominal voltage.
4.3 Information to be given in a detail specification 4.3.1 General Detail specifications shall be derived from the relevant blank detail specification. Detail specifications shall not specify requirements inferior to those of the generic or sectional specification. When more severe requirements are included, they shall be listed separately. 4.3.2 Outline drawing and dimensions There shall be an illustration of the inductor as an aid to easy recognition and for comparison of the inductor with others. Dimensions and their associated tolerances, which affect interchangeability and mounting, shall be indicated upon the drawing. All dimensions shall be stated in millimetres. The numerical values shall be given for the length of the body, the width and height of the body or for cylindrical types, the body diameter, and the length and diameter of the terminations. When necessary, for example when a number of items (inductance values/ voltage ranges) are covered by a detail specification, the dimensions and their associated tolerances shall be placed in a table below the drawing. When the configuration is other than described above, the detail specification shall state such dimensional information to describe the inductor adequately. When the inductor is not designed for use on printed boards, this shall be clearly stated in the detail specification.
4.3.3 Mounting The detail specification shall specify the method of mounting to be recommended for normal use and the method, which is mandatory for the application of the vibration and shock tests. The design of the inductor may be such that special mounting fixtures are required in its use. In this case, the detail specification shall describe the mounting fixtures and they shall be used in the application of the bump, shock and vibration tests. The specified heat sink shall be used in the application of the endurance test. 4.3.4 Ratings and characteristics The ratings and characteristics shall be in accordance with the relevant clauses of this sectional specification. Additional characteristics may be listed, when they are considered necessary to specify adequately the inductor for design and application purposes. 4.4 Insulated inductors for power line applications Insulated inductors may be built either with housing or with isolated wires where the isolation provides basic or reinforced insulation, e.g. TIW, FIW-wires, PVC-isolated wires, wires in insulation sleeves or the like. The isolated wires or the insulating materials used shall be in accordance with relevant IEC standards. Fully insulated winding wires (FIW) shall comply by certificate with IEC 60851 -5, IEC 6031 7-0-7 and IEC 6031 7-56.