I measured the impedance of some chokes i made in the past.
The influence of winding technique on the windingcapacity is clear.
btw i forget how much insulation i used for the "layers". I think it was 0,3mm.
The core i used was 0,05mm double c-core.
The influence of winding technique on the windingcapacity is clear.
btw i forget how much insulation i used for the "layers". I think it was 0,3mm.
The core i used was 0,05mm double c-core.
An externally hosted image should be here but it was not working when we last tested it.
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Sure, in an OPT you have many primaries in series, so winding capacitance will lower, but in an inductor there is no way, but vertical sectioning and/or increasing insulator.
Forget special winding techniques, they are beyond my winding lathe...😀
Perfect not exists.
The reason that i posted some measurements of my own transformer in another thread (unfortunately destroyed by some other forum member) was that that is the only thing what is really important (ok, some people believe in listening only but that is far more tricky).
So the technical results are important. People can ask questions about design parameters, not if the wire is red or blue ....
The reason that i posted some measurements of my own transformer in another thread (unfortunately destroyed by some other forum member) was that that is the only thing what is really important (ok, some people believe in listening only but that is far more tricky).
So the technical results are important. People can ask questions about design parameters, not if the wire is red or blue ....
No, I mean perfect layer technique IIRC to minimize capacitance between turns in the winding, is a complete nightmare to do.
Edit: Be free to post what you want about your transformers, is always interesting and a source of inspiration.
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Ahh, yes i agree.
btw if you have some measurements of your transformer you can make "plot" in a speadsheat as Excel.
btw2 i have some old test equipment what i can sell for : "as is" for free to you. Only shipment you have to pay.
I have to see what i have in my basement.....
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Tip#4 Interwinding insulation
We must be very cautious here, because voltages involved can be very high, mostly in OPT when secondaries are grounded.
The best of the best insulator is NOMEX, you can kill three birds with one stone
1- Insulation, about 27 KV/mm for 0.08mm NOMEX 410
2- Low dielectric constant, about 1.6 for 0.08mm NOMEX 410
3- Heat resistant
Five to seven layers of 0.08mm would be enough for most cases.
We must be very cautious here, because voltages involved can be very high, mostly in OPT when secondaries are grounded.
The best of the best insulator is NOMEX, you can kill three birds with one stone
1- Insulation, about 27 KV/mm for 0.08mm NOMEX 410
2- Low dielectric constant, about 1.6 for 0.08mm NOMEX 410
3- Heat resistant
Five to seven layers of 0.08mm would be enough for most cases.
The only measurements I have, is a comparative EI vs C core saturation, but I must search for them.
You are very kind my friend, and I appreciate so much your gesture, but even when I could to pay shipping, here is forbidden the import.
Thanks a lot anyway. 🙂
Forbidden import? Damn, what country do you live?
Anyway, if there is an opportunaty let me know. Maybe all or free.......
Anyway, if there is an opportunaty let me know. Maybe all or free.......
Yes, it is, but my magnetic materials provider is a little "Kiosk" and sell me NOMEX by weight, and I usually buy a few grams, in multiples of 50g, say 100g is about two meter long sheet 0.08mm, enough for a couple of OPT.
Better no to say, forum rules...😀
Thanks again. 🙂
popilin lives in Argentina, shipping from Europe will be hell expensive.
BTW, there are a lot of LCR meter schematics published in different magazines, so you can suggest poppilin something capable but not too complex.
I used toroidal variac, 50W wire-wound resistors and true RMS voltmeter to plot inductance/permeability curve. LCR meters usually use only fixed voltage, 0.6V or 1V.
This is Python function I use in conjunction with LibreOffice (you can convert it to whatever else program, its damn sinple).
__________________________
# Calculates inductance of the choke w/o DC bias.
# Choke is connected in series with resistor (R), powered from generator.
# E_R - AC voltage across resistor R.
def Get_L_test_AC(E_R, R, E_L, R_coil, f):
# Current over the coil.
I = E_R / R
# Impedance of the coil.
Z = E_L / I
# Reactance of the coil.
X = math.sqrt(Z**2 - R_coil**2)
return X/(2*math.pi*f)
__________________________
From L, number of turns and core geometry you can get value of permeability (mu).
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Interesting program, normally I use a 5VAC transformer and can "measure" Lp and Ls (leakage), In extreme cases I have a friend in university and access to HP vector impedance meter, and a lot more instruments, bad news is I must travel 200Km. 😀
Hi all
with so many specialists in transformers here, may i sugest something ? i have 2 irons wich i would like to make 2 transformers for EL 34 SE triode mode. what i have is M85 E and I made of M6 grain oriented, so i have a core of 13,5 sq cm. So can someone tell me how many turns and gauge of wire do i need for the primary ? secundary should be 8 ohms.
All the maths here is to much for me. If more details needed, please ask me. +B is 300 V.
Thanks
with so many specialists in transformers here, may i sugest something ? i have 2 irons wich i would like to make 2 transformers for EL 34 SE triode mode. what i have is M85 E and I made of M6 grain oriented, so i have a core of 13,5 sq cm. So can someone tell me how many turns and gauge of wire do i need for the primary ? secundary should be 8 ohms.
All the maths here is to much for me. If more details needed, please ask me. +B is 300 V.
Thanks
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Is a very complicated issue, and I can't answer without talk about politics, otherwise people couldn't understand in what country I live, neither Argentinians we know it for this time...😀
Hi, I do not consider myself as a specialist in transformers, but if you can put more info, maybe for tomorrow I can post a complete design as an example of how equations work.
I need: Primary impedance, power, primary DC current, lowest frequency and more details about core and coil former (geometry)
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