Epcos AG produces 7 standard sizes of of ETD cores.
In most cases, products of Russian electronics contain ETD cores made of basic N87 power ferrite brand that is intended for a use in frequency range of up to 500 kHz.
The advantages of using ETD configuration may be referred as a convenience of winding by thick wire and copper tape, large number of pins on winding frames providing a modularity of multi-winding transformer’s construction and also a low labor intensity on producing wrap-in products based on these configurations. Standard lines of horizontal and vertical winding frames help to optimize an arrangement of transformer on ETD core on printed circuit board. Considerable factor in favor of using these cores in new developments is also a wide use of all standard sizes of this configuration in products of Russian power electronics what signifies shorter delivery times and lesser supply prices.
Wide lines of ETD ferrite cores with gap issued in standard procurement provide an additional possibility to optimize used magnetic circuits for adjusting to required design value of gap.
Standard Sizes of Cores
| Standard Size | A [mm] | B [mm] | D1 [mm] | D2 [mm] | h1 [mm] | h2 [mm] |
| ETD 29 | 30,6-1,6 | 9,8-0,6 | min. 22,0 | 9,8-0,6 | 16,0-0,4 | 10,7+0,6 |
| ETD 34 | 34,0±0,6 | 11,1-0,6 | min. 25,4 | 11,1-0,6 | 17,5-0,4 | 11,8+0,6 |
| ETD 39 | 38,9±0,7 | 12,8-0,6 | min. 29,3 | 12,8-0,6 | 20,0-0,4 | 14,2+0,8 |
| ETD 44 | 43,8±0,8 | 15,2-0,8 | min. 32,5 | 15,2-0,8 | 22,5-0,4 | 16,1+0,8 |
| ETD 49 | 48,5±0,9 | 16,7-0,8 | min. 36,1 | 16,7-0,8 | 24,9-0,4 | 17,7+0,8 |
| ETD 54 | 54,5±1,3 | 19,3-0,8 | min. 40,1 | 19,3-0,8 | 27,8-0,4 | 19,8+0,8 |
| ETD 59 | 59,8±1,4 | 22,1-0,9 | min. 43,6 | 22,1-0,9 | 31,2-0,4 | 22,0+0,9 |
Information on frames and brackets recommended for a use with ETD cores may be accessed by opening pdf files specified in tables shown above.
Designation in Documentation
Example of EPCOS code explanation and designation in design documentation:
Measurement unit — piece (half-piece).
N87 ETD29/16/10 B66358GX187 — full name of ferrite core.
ETD29/16/10 — configuration and standard size of core.
B66358 — ETD29/16/10 standard size code.
87 — core is made of N87 ferrite matetial.
Additional Information
To decrease losses on transportation and storage, it is recommended (as possible) to order ETD cores and bobbins in multiples of amounts contained in factory package. Information on number of cores in standard factory foam plastic package is given in here.
