B65887E0160A087

## **Ferrites** 

## RM cores 

## RM14 

**Series/Type: B65887E0***A087** Date: 2009-10-23 Version: 1 

© EPCOS AG 2009. Reproduction, publication and dissemination of this data sheet, enclosures hereto and the information contained therein without EPCOS' prior express consent is prohibited. 

~~LT~~ **RM cores B65887E0***A087 RM14 B65887** 

## **Magnetic characteristics (per set)** 

l/A = 0.35 mm[-1] le = 70 mm Ae = 200 mm[2 ] Amin = 170 mm[2 ] Ve = 14000 mm 

## **Approx. weight** 74 g/set 

## **Delivery mode** sets 

## **Packing** 

Standard styrofoam tray 300 x 200 x 60 (mm) 

||~~1)~~||||
|---|---|---|---|---|
|Material|ALvalue~~1)~~<br>nH|s<br>mm|µe|Ordering code|
|N87|160 ±3%|app. 1.90|45|B65887E0160A087|
|N87|250 ±3%|app. 1.00|70|B65887E0250A087|
|N87|630 ±3%|app. 0.40|175|B65887E0630A087|



1) Measurement parameter: 10 kHz, 0.25 mT, 100 turns, room temperature. AL value is measured acc. to IEC62044-2. An appropriate wringing of cores with polished surface is used to improve reproducibility of the measurement. (It is recommended to rub the mating surfaces themselves six times in a circular or elliptic arc that matches the core profile before measuring AL value). 

SMP IN TCF FER PD 

2009-10-23 

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**RM cores B65887E0***A087 RM14 B65887** 

## **Cautions and warnings** 

## **Mechanical stress and mounting** 

Ferrite cores have to meet mechanical requirements during assembly and for a growing number of applications. Since ferrites are ceramic materials one has to be aware of their special behavior under mechanical load. 

Just like any ceramic material, ferrite cores are brittle and sensitive to any shock, fast changing or tensile load. Especially fast cooling rates under ultrasonic cleaning, high static and cyclic loads can cause cracks or failure of the ferrite cores. 

For detailed information see Data Book 2007, chapter “General – Definitions, 8.1”. 

## **Effects of core combination on AL value** 

Stresses in the core affect not only the mechanical but also the magnetic properties. It is apparent that the initial permeability is dependent on the stress state of the core. The higher the stresses are in the core, the lower the value for the initial permeability. Thus, the embedding medium should offer the greatest possible elasticity. 

For detailed information see Data Book 2007, chapter “General – Definitions, 8.2”. 

## **Heating up** 

Ferrites can run hot during operation at higher flux densities and higher frequencies. 

## **NiZn-materials** 

The magnetic properties of NiZn-materials can change irreversibly when exposed to strong magnetic fields. 

## **Processing notes** 

- The start of the winding process should be soft. Otherwise, the flanges may be destroyed. 

- Excessive winding forces may damage the flanges or squeeze the tube so that the cores can no longer be mounted. 

- Excessive soldering time at high temperature (>300 °C) may affect coplanarity or pin arrangement. 

- Not following the processing notes for soldering of the J-leg terminals may cause solderability problems at the transformer because of contamination with tin oxide (SnO) from the tin bath or burned insulation from the wire. For detailed information see Data Book 2007, chapter “Processing notes, 2.2”. 

- The dimensions of the pin hole arrangement are fixed and should be understood as an ideal recommendation for drilling the printed circuit board. In order to avoid problems when mounting the transformer, customers should make allowances for manufacturing tolerances in the drilling and pick-and-place processes by increasing the diameter of the pin holes. 

SMP IN TCF FER PD 

2009-10-23 

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|**RM cores**|**B65887E0***A087**|
|---|---|
|**RM14**|**B65887**|



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SMP IN TCF FER PD 

2009-10-23 

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