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Valves / Vacuum Tubes
EI VS C-Core for PP transformer question
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<blockquote data-quote="Ufudu" data-source="post: 599848" data-attributes="member: 16901"><p>Ampdog, yes, I thought it might be the non linear BH curve, so I tried a few quick things (based on your suggestions) this evening using a signal source and directly measuring the Hammond primary inductance's current and voltage. Not very scientific, (measuring only peak voltages) but just to get an idea what is happening:</p><p></p><p>At small signal (350mV, 100uA, 50Hz) I get correlation with the inductance meter (approx 11.5H)</p><p>At 2.8V pk 400uA I get 25H</p><p>At 6.4V pk 700uA I get 32H</p><p></p><p>So, there is something interesting going on here.</p><p></p><p>I then did a quick test by superimposing a dc current of 80mA and doing the same small signal test, but I found no measurable difference in inductance as the dc current varied from 0. </p><p></p><p>The latter test setup has some flaws (I used 2 Hammonds in parallel, one to feed the dc then multiply the measurement by 2...) so I will think of something different... need to think about this one... <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /></p></blockquote><p></p>
[QUOTE="Ufudu, post: 599848, member: 16901"] Ampdog, yes, I thought it might be the non linear BH curve, so I tried a few quick things (based on your suggestions) this evening using a signal source and directly measuring the Hammond primary inductance's current and voltage. Not very scientific, (measuring only peak voltages) but just to get an idea what is happening: At small signal (350mV, 100uA, 50Hz) I get correlation with the inductance meter (approx 11.5H) At 2.8V pk 400uA I get 25H At 6.4V pk 700uA I get 32H So, there is something interesting going on here. I then did a quick test by superimposing a dc current of 80mA and doing the same small signal test, but I found no measurable difference in inductance as the dc current varied from 0. The latter test setup has some flaws (I used 2 Hammonds in parallel, one to feed the dc then multiply the measurement by 2...) so I will think of something different... need to think about this one... :) [/QUOTE]
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Valves / Vacuum Tubes
EI VS C-Core for PP transformer question
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