IEC 63093-4:2019

IEC 63093-4 ®
Edition 1.0 2019-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Ferrite cores – Guidelines on dimensions and the limits of surface irregularities –
Part 4: RM-cores
Noyaux ferrites – Lignes directrices relatives aux dimensions et aux limites des
irrégularités de surface –
Partie 4: Noyaux RM
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IEC 63093-4 ®
Edition 1.0 2019-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Ferrite cores – Guidelines on dimensions and the limits of surface irregularities –

Part 4: RM-cores
Noyaux ferrites – Lignes directrices relatives aux dimensions et aux limites des

irrégularités de surface –
Partie 4: Noyaux RM
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.100.10 ISBN 978-2-8322-6615-1

– 2 – IEC 63093-4:2019 © IEC 2019
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Primary dimensions . 7
4.1 General . 7
4.2 Dimensions of RM-cores . 7
4.2.1 Principal dimensions . 7
4.2.2 Effective parameter and A values . 7
min
4.3 Main dimensions for coil formers . 7
4.3.1 Shape of coil former and pin numbering . 7
4.3.2 Dimensions of coil formers for RM-cores for the primary standard . 7
4.3.3 RM-cores intended particularly for power applications . 7
4.4 Pin locations and base outlines . 7
4.5 Spring recess . 8
4.6 Stud recess . 8
5 Mounting . 21
6 Limits of surface irregularities . 21
6.1 General . 21
6.2 Examples of surface irregularities . 21
6.3 Chips and ragged edges . 21
6.3.1 General . 21
6.3.2 Chip and ragged edges located on the mating surface . 21
6.3.3 Chips and ragged edges located on other surfaces . 22
6.4 Cracks . 24
6.5 Pull-out . 26
6.6 Crystallites . 27
6.7 Flash . 27
6.8 Pores . 28
Annex A (informative) RM-core design . 29
A.1 General . 29
A.2 Pin locations and base outlines . 29
A.3 Design considerations and dimensions . 29
A.4 Practical considerations . 30
Annex B (normative) Guidance for measuring clamping forces relevant to RM-core
tests . 31
B.1 Test conditions and clamping forces . 31
B.2 Clamping procedure . 31
Annex C (informative) Examples of allowable areas of chips . 33
Bibliography . 34

Figure 1 – Dimensions of RM-cores . 9
Figure 2 – Dimensions of low-profile RM-cores . 10
Figure 3 – Dimensions of spring recess . 12
Figure 4 – Dimensions of stud recess . 13

Figure 5 – Main dimensions of coil formers for RM-cores . 14
Figure 6 – Pin locations and base outlines viewed from the underside of the board . 16
Figure 7 – Dimensions of specific features . 18
Figure 8 – Pin locations and base outlines viewed from the underside of the board . 20
Figure 9 – Examples of surface irregularities . 21
Figure 10 – Chips on mating surfaces . 22
Figure 11 – Location of cracks – Top view . 24
Figure 12 – Location of cracks – Bottom view . 24
Figure 13 – Dimension W . 26
Figure 14 – Location of pull-out . 26
Figure 15 – Pull-out in the clamping recess area . 27
Figure 16 – Location of a crystallite . 27
Figure 17 – Location of a flash . 28
Figure 18 – Location of pore . 28
Figure B.1 – Mounting device. 31

Table 1 – Dimensions of RM-cores . 9
Table 2 – Dimensions of low-profile RM-cores . 10
Table 3 – Effective parameter and A values for RM-cores . 11
min
Table 4 – Effective parameter and A values for low-profile RM-cores. 12
min
Table 5 – Dimensions of spring recess . 13
Table 6 – Dimensions of stud recess . 13
Table 7 – Dimensional limits for coil formers for RM-cores . 14
Table 8 – Dimensional limits for coil formers for low-profile RM-cores . 15
Table 9 – Dimensions of specific features . 19
Table 10 – Area and length reference of irregularities for visual inspection . 23
Table 11 – Limits for cracks . 25
Table 12 – W dimensions .
...