IEC 62317-4-2005 pdf – Ferrite cores – Dimensions – Part 4: RM-cores and associated parts.
1 Scope This part of IEC 62317 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of RM-cores and low-profile RM-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 specifies the test conditions and clamping forces to be used for inductance measurement. The general considerations that the design of this range of cores is based upon are given in Annex A. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60097:1991, Grid system for printed circuits IEC 60205:2001, Calculation of the effective parameters of magnetic piece parts 3 Primary standards Compliance with the following requirements ensures mechanical interchangeability of complete assemblies and wound coil formers. 3.1 Pin locations and base outlines These shall be as shown in Figure 6 and Figure 8 (for power applications), in which the base is viewed from the pin side, i.e. from the underside of the printed wiring boards. The pins shall fit into holes according to IEC 60097, the nominal hole diameter being: – 1 mm when the shortest distance between pins is 2,54 mm; – 1,3 mm when the shortest distance between pins is 2 54 , 2 mm or more. 3.2 Dimensions of RM-cores The dimensions of RM-cores shall be as given in Table 1 and the low-profile RM-cores shall be as given in Table 2.
3.3 Shape of coil former and pin numbering When the coil former is viewed from the pin side, the pins shall be numbered in a clockwise direction. Pin 1 shall be a corner pin, or the pin immediately to the right of a corner, and closest to the base outline. For asymmetrical arrangements, pin 1 shall be at the side with the largest number of pins. The coil former shall show an asymmetry which shall preferably be visible (or detectable) when the assembled inductor is held with the pins downwards. This asymmetry shall clearly indicate pin 1. For pin numbering of recommended core patterns and for recommended asymmetrical pin arrangements, see 3.1. NOTE It is not required that the pin numbers be marked on the coil former. 3.4 Effective parameter values The effective parameter values for cores having the dimensions given in 3.2 and 3.5 are as shown in Table 3 and Table 4. 3.5 Spring recess RM-cores shall have recesses which allow the core halves to be held together by two spring clamps snapping into these recesses. The recesses consist of a flat spring rest and a locking ridge. The dimensions are given in Table 5; the profile of this spring recess is not defined but the limit dimensions shall be complied with. 3.6 Stud recess Those RM-cores with centerpost holes may have recesses for the fixed part of the adjusting device with dimensions in accordance with Table 6. These dimensions are not mandatory for manufacturers who supply cores with the fixed part of the adjusting device attached.