EER CORES
ETD CORES


Description of the "E" patterns
The "E" patterns are sought that are easy to assemble, could be interleave to minimize gap effects, and would minimize waste. Since "E" cores have two open coil sides, they provide substantial room to bring high current lead wires out from the coil. It is easier to achieve high voltage electrical isolation with an "E" core. In the typical "E" lamination, the center leg (one of three legs) is twice the width of either outer leg. In theory, magnetic flux flowing out of the center leg divides equally and flows into the outer two "E" core legs. Since the outer legs handle half the flux they only need to have half the cross-section that the center leg has. It is easier to achieve high voltage electrical isolation with an "E" core than with a pot core.
Presentation of EER-core and ETD-core
EER-core and ETD-core are examples of type "E" cores with round center legs. The combined cross section of the two outer legs of EER cores and ETD cores should equal or exceed that of the center leg. The core stack is a stack of laminations and the typical stack has core legs of rectangular cross-section. Typically the inductor or transformer coil is placed over the center core leg. To minimize winding resistance (hence also minimize winding losses) it is desirable to have a round center leg. A round center leg also eliminates the sharp bend encountered when winding wire around a rectangular leg; consequently a round center leg permits use of larger wire. Achieving round center legs with laminations is possible but very impractical. With the development of powdered cores and ferrite cores it became practical to have a round center leg. EER-core and ETD-core type, such as EER42, EER40, EER20, EER35, EER28, EER30, EER34, EER43, EER45, EER50, etc, ferrite cores are developed for higher power higher frequency switching transformers.
Application of EER-core and ETD-core
EER cores and ETD cores are usually larger, but have a wide winding area, which makes them particularly good for higher power designs or multiple output designs. Remember a larger core size will be needed for a margin wound type transformer than for a triple insulated type to allow room for the margins. EER cores with round center leg offer ideal features for the design of SMPS transformers chokes. We offer various EER cores and ETD cores, including EER42, EER40, EER20, EER35, EER28, EER30, EER34, EER43, EER45, EER50, EER49, EER25.5, EER55, EER54, EER53, ETD29, ETD34, ETD39, ETD49, ETD44, ETD10, ETD41, ETD32, ETD59, ETD31, and ETD22. Please find our details of ETD-core and EER-core by types and dimensions data shown as below.
Type | Dimensions(mm) | |||||
---|---|---|---|---|---|---|
A | B | C | D | E | F | |
EER25 | 25.3±0.6 | 9.3±0.3 | 7.5 ± 0.3 | 7.5 ± 0.3 | 19.8 | 6.2 ± 0.3 |
EER28A | 28.5±0.6 | 14.0 ± 0.3 | 11.4 ± 0.3 | 9.9±0.3 | 21.2 | 9.6±0.3 |
EER28B | 28.5±0.6 | 16.9 ± 0.3 | 11.4 ± 0.3 | 9.9 ± 0.3 | 21.2 | 12.5 ± 0.3 |
ETD29 | 29.8±0.8 | 15.8 ± 0.2 | 9.5 ± 0.3 | 9.5 ± 0.3 | 22.0 | 11.0 ± 0.3 |
EER30 | 30.0 ± 0.8 | 17.5 ± 0.3 | 11.2 ± 0.3 | 9.9 ± 0.3 | 22.5 | 12.6 ± 0.3 |
ETD34 | 34.2 ± 0.8 | 17.3 ± 0.2 | 10.8 ± 0.3 | 10.8 ± 0.3 | 25.6 | 12.1 ± 0.3 |
EER35A | 35.0 ± 0.7 | 21.0 ± 0.3 | 11.3 ± 0.4 | 11.3 ± 0.3 | 25.3 | 15.0 ± 0.3 |
EER35/34B | 35.0 ± 0.7 | 16.8 ± 0.3 | 11.3 ± 0.4 | 11.3 ± 0.3 | 25.3 | 10.8 ± 0.3 |
EER35C | 36.0 ± 0.7 | 21.6 ± 0.4 | 11.3 ± 0.4 | 11.3 ± 0.4 | 26.5 | 15.6 ± 0.4 |
EER37 | 36.0 ± 0.6 | 20.7 ± 0.3 | 11.3 ± 0.3 | 11.3 ± 0.3 | 27.6 | 14.7 ± 0.3 |
ETD39 | 39.1 ± 0.9 | 19.8 ± 0.2 | 12.6 ± 0.4 | 12.5 ± 0.3 | 29.3 | 14.6 ± 0.4 |
EER40A | 40.0 ± 0.8 | 22.4 ± 0.3 | 13.3 ± 0.3 | 13.3 ± 0.3 | 29.0 | 15.4 ± 0.3 |
EER40B | 44.0 ± 0.8 | 22.4 ± 0.3 | 13.3 ± 0.3 | 13.3 ± 0.3 | 29.3 | 15.4 ± 0.3 |
EER40C | 40.0± 0.7 | 22.9 ± 0.3 | 13.3 ± 0.3 | 13.3 ± 0.3 | 29.5 | 15.9 ± 0.3 |
EER40D | 40.2± 0.5 | 21.4± 0.3 | 15.5± 0.3 | 15.5± 0.3 | 29.4 | 15.4± 0.3 |
EER40E | 40.0 +0.6 -0.5 |
23.0± 0.3 | 13.3± 0.3 | 13.3± 0.3 | 29.0 | 16.0± 0.3 |
EER40F | 41.0max | 22.8±0.3 | 13.3±0.4 | 13.3±0.3 | 29.5 | 15.8±0.3 |
EER40G | 40.8 +0.1 -0.5 |
21.3±0.2 | 15.0±0.2 | 14.0±0.25 | 30.7 | 15.3±0.2 |
EER40H | 41.0±0.7 | 24.0 + 0.3 - 0 |
13.0 +0 -0.3 |
13.0 +0 -0.3 |
30.0 | 17.0 +0.3 -0 |
EER42A | 42.0 ±0.8 | 22.0 ±0.3 | 15.2 +0.3 -0.2 |
15.2 +0.3 -0.2 |
30.5 | 15.4 ±0.3 |
EER42B | 42.0 ±0.8 | 21.2 ±0.3 | 15.2 +0.3 -0.2 |
15.2 +0.3 -0.2 |
30.5 | 15.4 ±0.3 |
ER43A | 43.0 ±0.8 | 22.7 +0.25 -0.2 |
15.5 ±0.4 | 15.5 ±0.3 | 30.7 | 15.7 ±0.3 |
EER43B | 43.0 ±0.8 | 22.4 ±0.3 | 15.5 ±0.4 | 15.0 ±0.3 | 31.0 | 15.4 ±0.3 |
ETD44 | 44.0 ±1.0 | 22.3 ±0.2 | 14.8 ±0.4 | 14.8 ±0.4 | 33.3 ±0.8 | 16.5 ±0.4 |
EER45 | 45.0 ±0.8 | 24.0 ±0.3 | 14.8 ±0.4 | 14.8 ±0.3 | 32.0 | 17.6 ±0.3 |
EER49A | 49.0 ±0.8 | 26.2 ±0.4 | 17.0 ±0.5 | 17.0 ±0.5 | 36.5 | 18.7 +0.3 -0.2 |
EER49B | 49.0 ±1.0 | 27.0 ±0.3 | 17.2 ±0.4 | 17.2 ±0.3 | 36.5 | 18.7 ±0.3 |
ETD49 | 49.0 ±1.0 | 24.7 ±0.3 | 16.3 ±0.4 | 16.3 ±0.4 | 36.1 | 18.1 ±0.4 |
EER50 | 50.5 ±0.8 | 27.0 ±0.3 | 18.7 ±0.4 | 18.7 ±0.4 | 38.0 | 18.7 ±0.3 |
EER53 | 53.2 ±0.8 | 23.2 ±0.3 | 21.5 ±0.3 | 20.0 +0.2 -0.3 |
38.7 | 16.3 ±0.3 |
EER54 | 54.2 ±0.8 | 25.1 ±0.4 | 18.9 ±0.4 | 18.9 ±0.3 | 40.5 | 17.5±0.3 |
EER55A | 56.0 ±0.8 | 30.7 ±0.3 | 20.4 ±0.3 | 20.4 ±0.3 | 44.0 | 22.9±0.3 |
EER55B | 55.9 ±1.0 | 29.0 ±0.3 | 24.3 ±0.5 | 20.2 ±0.3 | 43.5 | 20.4±0.3 |
Type | Core parameter | weight (g/pr.) | Al(nH/N2 ) | |||||
---|---|---|---|---|---|---|---|---|
C1 (mm-1) | Ae (mm2 ) | Ie (mm) | Ve (mm3 ) | F2B (±25%) | F2BD (± 25%) | F2B1 ( ±25%) | ||
EER25 | 1.09 | 44.3 | 48.3 | 2140 | 12 | 2100 | 2050 | 1920 |
EER28A | 0.79 | 82.1 | 64 | 5254 | 28 | 3120 | 3080 | 2870 |
EE28B | 0.86 | 85.6 | 73.2 | 6266 | 33 | 2100 | 2660 | 2520 |
ETD29 | 0.95 | 73.6 | 70.6 | 5196 | 28 | 2500 | ≥2100 | 2200 |
EER30 | 0.99 | 85.5 | 75.4 | 6673 | 32 | 2800 | 2600 | 2500 |
ETD34 | 0.81 | 97.1 | 78.6 | 7632 | 40 | 2600 | 2450 | 2400 |
EER35A | 0.84 | 107 | 90.8 | 9716 | 53 | 2960 | 2580 | 2600 |
EER35/34B | 0.68 | 107 | 72.8 | 7790 | 51 | 3100 | 2770 | 2770 |
EER35C | 0.84 | 107 | 90 | 9630 | 55 | 3100 | 2700 | 2700 |
EER37 | 0.8 | 112.1 | 90.5 | 10149 | 52.5 | 2960 | 2580 | 2600 |
ETD39 | 0.737 | 125 | 92.1 | 1151 | 60 | 3240 | 2800 | 2700 |
EER40A | 0.66 | 149 | 98 | 14602 | 78 | / | 3500 | 3500 |
EER40B | 0.68 | 149 | 102 | 15198 | 78 | / | 3500 | 3500 |
EER40C | 0.67 | 149 | 100 | 14900 | 78 | / | 3400 | 3400 |
EER40D | 0.50 | 187.7 | 93.9 | 17415 | 78 | 3830 | 3800 | 3300 |
EER40E | 0.65 | 151 | 98.2 | 14828 | 77 | / | 3300 | 3300 |
EER40F | 0.65 | 151 | 98.1 | 15215 | 78 | / | 3300 | 3300 |
EER40G | 0.609 | 158 | 96.3 | 15230 | 80 | / | 3600 | 3600 |
EER40H | 0.7 | 145 | 102.8 | 14906 | 80 | / | 3200 | 3200 |
EER42A | 0.547 | 183 | 96.3 | 17623 | 94 | / | 4500 | 4500 |
EER42B | 0.528 | 183.7 | 96.9 | 17800 | 92 | / | 4400 | 4400 |
EER42/C | 0.5 | 155.3 | 97.5 | 15137 | 96 | / | 3500 | 3400 |
EER43A | 0.5 | 194 | 98.0 | 19821 | 105 | / | 4500 | 4500 |
EER43B | 0.5 | 194 | 96.8 | 19584 | 102 | / | 4500 | 4500 |
ETD44 | 0.59 | 173.0 | 103.0 | 17720 | 94 | / | 4110 | 4000 |
EER45 | 0.6 | 189.5 | 105.0 | 19894 | 108 | / | 5000 | 4670 |
EER49A | 0.5 | 235.8 | 116.0 | 27357 | 112 | / | 6800 | 6250 |
EER49B | 0.5 | 241 | 118 | 28460 | 148 | 3500 | 6500 | 6030 |
ETD49 | 0.534 | 217.6 | 112.2 | 24417 | 124 | 3700 | 3700 | 4400 |
EER50 | 0.437 | 277.5 | 117.6 | 32637 | 170 | / | 5730 | 5300 |
EER53 | 0.338 | 319.5 | 105.9 | 33828 | 170 | / | 6200 | 6200 |
EER54 | 1.0 | 594.1 | 48.7 | 28958.2 | 181 | / | 4800 | 4800 |
EER55A | 0.62 | 303.1 | 188.2 | 41896.1 | 220 | / | 7100 | |
EER55B | 0.36 | 353.8 | 128.7 | 45533 | 228 | / |