Epcos AG issues 5 standard sizes of PM ferrite cores intended for a use as magnetic circuits of high-capacity power transformers operating in frequency range of up to 30 kHz.
PM series derived its name from English word set (for POT core MODULE) and is characterized by high compactness and modularity of construction.
Geometrical Dimensions
Geometrical dimensions of PM ferrite cores issued by Epcos AG.
| Standard Size | a [mm] | b [mm] | c [mm] | d1 [mm] | d2 [mm] |
| PM 50/39 | 50,0-1,7 | 39,0+1,3 | min. 23,4 | 20,0-0,6 | 5,4+0,2 |
| PM 62/49 | 62,0-2,0 | 48,8+1,5 | min. 29,0 | 25,5-0,8 | 5,4+0,2 |
| PM 74/59 | 74,0-2,5 | 57,5+1,8 | min. 34,0 | 29,5-1,0 | 5,4+0,2 |
| PM 87/70 | 87,0-3,0 | 67,1+2,1 | min. 39,4 | 37,7-1,0 | 8,5+0,3 |
| PM 114/93 | 114,0-4,5 | 88,0+3,7 | min. 52,0 | 43,0-1,4 | 5,4+0,4 |
| Standard Size | f [mm] | g [mm] | h [mm] | H1 [mm] | H2 [mm] |
| PM 50/39 | max.23,0 | 1,2+0,2 | 5,0-0,4 | 26,4+0,8 | 39,0-0,4 |
| PM 62/49 | max.28,5 | 1,2+0,2 | 4,0+1,0 | 33,4+0,8 | 49,0-0,4 |
| PM 74/59 | max.32,4 | 2,5+0,4 | 4,0+0,4 | 40,7+0,8 | 59,0-0,6 |
| PM 87/70 | max.36,0 | 3,5+0,4 | 5,0-0,4 | 48,0+0,8 | 70,0-0,8 |
| PM 114/93 | max.45,0 | 4,0 | 5,3+0,4 | 63,0+1,6 | 93,0-1,0 |
Frames for PM50/39, PM62/49, PM 74/59, PM87/70 ferrite cores are issued in version with or without pins for mounting on printed circuit board.. Frames for PM114/93 series of larger ferrites are issued in version without pins. Drawings of frames and mounting brackets for PM cores of Epcos AG may be accessed by opening pdf file from table shown above.
Designation in Design Documentation
Measurement unit — set
N87 PM114/93 B65733-A-R87
B65733 — PM114/93 standard size code
87 — core is made from N87 ferrite material
Nomenclature of PM Cores without Gap
| Standard Size | Material | Order code | AL [nH/turn²] | ∑l/A [mm-1] |
le [mm] | Ae [mm²] | Ve [mm³] |
| PM 50/39 | N27 N87 |
B65646-A-R27 B65646-A-R87 |
7400±25% 7400±25% |
0,227 | 84,00 | 370,0 | 31000 |
| PM 62/49 | N27 N49 N87 |
B65684-A-R27 B65684-A-R49 B65684-A-R87 |
9200±25% 9200±25% |
0,191 | 109,0 | 570,0 | 62000 |
| PM 74/59 | N27 N87 |
B65686-A-R27 B65686-A-R87 |
10000±25% 10000±25% |
0,162 | 128,0 | 790,0 | 101000 |
| PM 87/70 |
N27 |
B65713-A-R27 B65713-A-R87 B65713-A-R92 |
12000±25% 12000±25% |
0,16 | 146,0 | 910,0 | 330000 |
| PM 114/93 | N27 N87 |
B65733-A-R27 B65733-A-R87 |
16000±25% 16000±25% |
0,116 | 200,0 | 1720,0 | 344000 |
Nomenclature of PM Cores with Gap
| Standard Size | Material, AL [nH/turn²] | Order code | Gap [mm] |
| PM 50/39 | N27 PM 50/39 Al=100 N27 PM 50/39 Al=250 N27 PM 50/39 Al=630 N27 PM 50/39 Al=1600 |
B65646-A100-A27 B65646-A250-A27 B65646-A630-A27 B65646-A1600-J27 |
2,00 0,63 |
| PM 62/49 | N27 PM 62/49 Al=234 N27 PM 62/49 Al=315 N27 PM 62/49 Al=630 N27 PM 62/49 Al=1600 N27 PM 62/49 Al=4000 |
B65684-A234-A27 B65684-A315-A27 B65684-A630-A27 B65684-A1600-J27 B65684-A4000-L27 |
2,60 1,10 |
| PM 74/59 | N27 PM 74/59 Al=315 N27 PM 74/59 Al=630 N27 PM 74/59 Al=4000 |
B65686-A315-A27 B65686-A630-A27 B65686-A4000-L27 |
3,80 1,50 |
| PM 87/70 | N27 PM 87/70 Al=270 N27 PM 87/70 Al=400 N27 PM 87/70 Al=1000 N27 PM 87/70 Al=2500 N27 PM 87/70 Al=5000 |
B65713-A270-A27 B65713-A400-A27 B65713-A1000-A27 B65713-A2500-J27 B65713-A5000-L27 |
3,50 0,14 |
| PM 114/93 | N27 PM 114/93 Al=330 N27 PM 114/93 Al=630 N27 PM 114/93 Al=6300 N27 PM 114/93 Al=8000 |
B65733-A330-A27 B65733-A630-A27 B65733-A6300-L27 B65733-A8000-L27 |
3,80 0,22 |
Example of assembling a set on PM-configured cores
Additional Information
To decrease losses on transportation and storage, it is recommended (as possible) to order ferrite cores, bobbin and clamps of PM-configuration in multiples of amounts contained in factory package. Information on number of cores in standard factory package is given in this page.
