IEC 60938-1 pdf – Fixed inductors for electromagnetic interference suppression – Part 1: Generic specification
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 that 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 that is mandatory for the application of the vibration and shock tests. The design of the inductor can 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 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 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 Insulated inductors may be built either with a housing, or with isolated wires whose isolation provides basic 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. Instead of fulfilling requirements for clearance and creepage inside inductors, the windings may be insulated by potting or insulation sleeves or the windings may be built from wires with basic insulation like TIW, FIW, PVC-isolated wires or the like. Insulation materials used between terminals and windings, for housing or potting shall be certified to a minimum rating of V-2, VTM-2 or HF-2 in accordance with IEC 60695-11-10 and IEC 60695 ‑11‑20 (or UL 94) at the appropriate minimum thickness, which is determined by the smallest thickness of insulation in direct contact with a conductor.
4.5 Marking Necessary marking in accordance with the relevant specifications shall be prescribed in the detail specification. Deviations from these requirements shall be listed separately and the reason for them shall be stated specifically in the detail specification. The sectional specification shall indicate the identification criteria and other information to be shown on the inductors and its packaging. The order of priority for marking small components shall be specified. When coding is used for inductance values, tolerance or date of manufacture, the method shall be selected from those given in IEC 60062.
5 Tests and measurement procedures
5.1 General The relevant specification shall contain the tests to be made, which measurements are to be made before and after each test or sub group of tests and the sequence in which they shall be carried out. The stages of each test shall be carried out in the order written. The measuring conditions shall be the same for initial and final measurements.
5.2 Standard atmospheric conditions Unless otherwise specified, all tests and measurements shall be made under standard atmospheric conditions for testing as given in Table 1:
Before measurements are made, components shall be stored at the measuring temperature for a period sufficient to allow the entire component to reach this temperature. The period stated for recovery at the end of a test is normally sufficient for this purpose. When measurements are made at a temperature other than the specified temperature, the results shall be corrected to the specified temperature.
The ambient temperature during the measurements shall be stated in the test report. When tests are conducted in a sequence, the final measurements of one test may be taken as the initial measurements for the succeeding test. During measurements, the component shall not be exposed to draughts, direct sunlight or other influences likely to cause errors. Recovery shall also take place under the standard atmospheric conditions, unless otherwise specified in the relevant specification. For reference conditions, referee conditions or recovery under closely controlled conditions, refer to IEC 60068-1.