| Electronics > Projects, Designs, and Technical Stuff |
| "over current" use of a Pulse transformer - ( or an alternative ) |
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| ogden:
--- Quote from: mrpackethead on December 29, 2018, 08:25:43 am ---What we dont' know are what the 'real' limits of 'were it will work to. Please stay on topic, or find another thread to pollute. Its not even about is this a good idea. Its about understanding what will happen if you push past the datasheets limit. --- End quote --- Well.. I already tried to bring your attention to thermal derating curve, but seems you were busy profiling me. You would want to calculate heat dissipated by transformers and chokes at target current (1A). Worth to consider slightly bigger magnetics having lower internal DC resistance, rather than spent BOM money and real estate in heat spreaders. Disclaimer: englisch is not my native language, please respect this fact. |
| mrpackethead:
Some good news, at 1A current ( some 100mA over my target current ) the transformer does not overheat. It does get warm. ( around 91C, some 71C over the ambient heat ). I tryed attaching some heatsinks and it makes very little difference. I put this down to that the wire is not well coupled thermally to the ferrite, and the ferrite itself has quite poor thermal conductivity ( roughly 100x less than aluminium ). Some futher testing with forced air ( which is not an issue, as this is going to have fans anyway ), dropped the ferrite temp to just 54C. The physical design of the transformer lends itself to being able to have forced air coming underneath it, via a cut out in the pcb.. This also means it does not require any additional parts. I am about to start testing for DC Bias and inductance versus temp. With 30mA of bias it did not fall over. |
| mrpackethead:
This is what i'm going to do to keep these cool. ( it works in a hacked up test, now to more formally test on a designed pcb ) Air will be forced up from under the pcb, past the wire which is where the heat is. This is going to be quite simple to implement |
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