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Inductor and transformer design methodology!

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My mean is set them together carefully .
If you have a distance between them , however a bit , your calculations will change , because inductance per turn will change . consider this is your E : E and this is your I : I
correct setting : EI wrong setting : E I .
 
By the way , if you need gap space , you should , measure inductance per turn when you created your desired gap , thus it is possible that you need more turns as N1 ( because permeability will decrease )
Good luck
Goldsmith
 
I rather expect a problem in inductance measurement. But without knowing the instrument type, I won't guess about details.
 

i hv UN-T LCR meter

starting from 100uH, now i hve 350uH after cleaning all the transformer
 

can you take a picture from your core and your wound inductor , and the number that LCR meter showing per one turn , and the number that it shows instead of 13 turn . please ?
 
thx for ur kind concern. today i implemented that transformer. becz of MUR3020 and inductor, voltage was little dropped. but overall the response was great. tomorrow i il increase the secondary turn to increase the power.
 

Is that mean , that your LCR meter could show you the correct number , at last ? If yes , good .
By the way , i have designed all of my magnetic elements with this method ( even at my transmitters )
Good luck
Goldsmith
 
the calculated value of the secondary turns was 2. but becz of my power requirements, i wind 4 turn (total 8 turns becz of center tap), and regulate it by the PWM op-amp feedback.

and now i am working on +12 and -12V winding.
 


Dear samhtcandroid
Hi
About your first question , you should look for both of them ! did you read them carefully ? i told what you should do at those literatures .
And for question number two : yes , you should select your core at first .
Best Wishes
Goldsmith
 
Dear chemelec
Hi
The formula that you suggested , is a general way , but it has a problem ! and it is the reason that i didn't use it more than some little times , at some years ago , and after that problem i thought , and these ( the ways that i told at first of this thread ) , brought in my mind . so what is the problem of your way : it is simple , you'll find the value of AL in datasheet of each core simply , but as you probably know , there isn't any even things available in this world that are similar together exactly . hence the suppose that you have two PQ4040 core , the AL for both of them are different together . i hope that you got my meaning .
Best Regards
Goldsmith
 
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but as you probably know , there isn't any even things available in this world that are similar together exactly . hence the suppose that you have two PQ4040 core , the AL for both of them are different together . i hope that you got my meaning .
Click to expand...

They shoud be Fairly Close to the same.
But it also depend on the GAP you use.

I "Don't use the Manufacturers", AL Values.
I wind a specific number of turns on one, than use the formula to Calculate the "Correct AL Value" for the "Particular core and Gap", that I have on my ferrite.

I find that it than works correctly with the Same Other ferrites, made in the same way.

I MAKE MANY Such Transformers and Inductors.
 

There are several prerequisites to get correct inductance values from L = n²*Al
- as a trivial point, trustworthy reference measurements. May be a problem with extreme n2/n1 ratios, e.g. n1=1
- the core setup, particularly exact gap width must not change between measurements, see previous discussion
- L ~ n2 is only valid if windings are perfectly magnetically coupled, in other words sharing the same flux.

Obviously the latter condition isn't fulfilled for open magnetic pathes, e.g. a ferrite rod or bobbin core. But also cores with closed magnetical path have some leakage inductance that shows up when comparing windings of different geometry.
 

goldsmith said:
well . i forgot to talk about what core we can select for .
Ok tomorrow , i'll attach a table of power instead of core .
( it's table is common with the other methods , such as methods that you can see at pressman's book or the other books .)
Good luck
Goldsmith
Click to expand...

I thought you were going to post a power table for example what size Core should be used for required Watts

for example

I use a EE25 Core for 15Volts 1.8 Amp, but I am not sure if more power can be attained from this core size

I want to make a 1100 watt converter from 220 VAC to 56 Volt DC
Now what core size should I use ?
 

Hi insider ,
Thank you for your remark and sorre because of that i forgot it completely there is some weeks that i'm pretty busy . i will try to attach it but if i forgot , send a PM to me for recall .
again sorry because i forgot it .
BTW : however it depends on your frequency but i think for 1100w a PQ4040 seems good .
Best Wishes
Goldsmith
 
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Dear Goldsmith

cant find a PQ4040 in the market here,
I have EE42 and EE55 available can they be used instead ?

specs for the supply are, freq 100khz, input 220VAC, output 56V 20A

will try a SEPIC configuration first, if I fail to get good results then will try a push pull mode.

best regards
Fahim Baig
 

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