Pieter what did you say?
If the 20:1 is the ratio, the turns MUST be the same with the SAME BOBBINS!!!! and different wire
The Litz will occupy more space of course
Walter
If the 20:1 is the ratio, the turns MUST be the same with the SAME BOBBINS!!!! and different wire
The Litz will occupy more space of course
Walter
this:
and may i add, is the winding geometry the same? same number op primary/secondary sections?
and may i add, is the winding geometry the same? same number op primary/secondary sections?
The geometry is the same.
The sections are the same; with a great difficult of the man who wounded it with a goal to make them more similar possible.
The volume of occupation is different of course; in this case we are at the limit as occupation.
The next one is a bigger C core for a s.e. with 300B / 2A3 just to reach more L
Walter
The sections are the same; with a great difficult of the man who wounded it with a goal to make them more similar possible.
The volume of occupation is different of course; in this case we are at the limit as occupation.
The next one is a bigger C core for a s.e. with 300B / 2A3 just to reach more L
Walter
Walter, I mean the "bobbin" the plastic support for the windings.
Take a look:
It do not seems you used the same bobbin...
Take a look:
An externally hosted image should be here but it was not working when we last tested it.
It do not seems you used the same bobbin...
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In my limited knowledge, litz wire take advantage only when the penetration depth of the magnetic field inside the copper area is of the same magnitude of the copper radius of the wire, what only happens at higher frequencies. I know it is valid mainly from 100KHz and above.
While I am waiting patiently for a result to determine whether Litz wire is really effective at 100KHz, opposite to classic findings that it is not, I would respectfully ask that the technical and the commercial sides be split please? This devides Walters attention and clouds the discussion at present.
As an EE I am more interested in seemingly contradictory findings regarding the effects of Litz wire. One accepts that language may be somewhat of a problem (no offence Walter, my knowledge of Italian is limited to operatic titles!) and I would echo Tony's advice that Walter keeps to technical aspects for now.
As said earlier, I myself have experienced several % spread in characteristics because of unavoidable mechanical differences in winding otherwise identical transformers. To me this is still a factor although one can accept that it may be impossible for Walter to quickly have several examples of the same thing at present. [I will go back to given results (memory fades with age 🙁 ) and have another look at whether anything was shown which might not fall within experimental tolerances.]
As an EE I am more interested in seemingly contradictory findings regarding the effects of Litz wire. One accepts that language may be somewhat of a problem (no offence Walter, my knowledge of Italian is limited to operatic titles!) and I would echo Tony's advice that Walter keeps to technical aspects for now.
As said earlier, I myself have experienced several % spread in characteristics because of unavoidable mechanical differences in winding otherwise identical transformers. To me this is still a factor although one can accept that it may be impossible for Walter to quickly have several examples of the same thing at present. [I will go back to given results (memory fades with age 🙁 ) and have another look at whether anything was shown which might not fall within experimental tolerances.]
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Thx Johan for this post.
It seems impossible, sometimes, to speak only with a tech language ( and test results).
I can have protos only in the time that the manifact. can spend hours to me, then I have to pay it. This means that I have to wait 10-20 days.
I know that my strange english can be a limit
Walter
It seems impossible, sometimes, to speak only with a tech language ( and test results).
I can have protos only in the time that the manifact. can spend hours to me, then I have to pay it. This means that I have to wait 10-20 days.
I know that my strange english can be a limit
Walter
IMO the effectiveness at HF is independent of "litz or not to litz" problem.
Most of the litz wire has -relatively- thick outer insulation, in good case it is made of cotton or silk.
The spacing -due to the insulation- of primary turns -if the winder is do good job- results lower capacity, better HF transfer.
I'm not convinced, that this improvement originate from the litz, rather than better spacing.
Few years ago our little DIY community in Hungary experimented with cottton/silk insulated (40-60 years old!) wires as tube amplifier output transformer's primary. The improvement was significant: better HF response, airy and accurate sounding.
But....we used solid core wires with cotton/silk insulation.
These ancient wires -especially the three layer silk insulated- are rare (and getting more expensive).
As our proverb said: Rare as white raven. 🙂
Warning that it also increases leakage inductance, making things worse at HF side of the spectrum, and reduces coupling between windings.
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Not necessarily, from Maxwell’s equations
∇. D = 4πρ
Integrating
∫(∇. D) dV = ∫ε (∇ . E) dV = ∮ ε E . dS = ε E S = ∫4πρ dV = 4πQ
Then
E = 4πQ / ε S (*)
Also
E = - ∇φ
For one dimensional case
E = - dφ/dx
Integrating
E ∆x = E d = ∆φ = V (**)
From definition of capacitance
C = Q / V (***)
Combining (*), (**), and (***)
C = ε S / 4π d
Using this approximation, with the normal magnet wire you get less d, but on the other hand, with the Litzendraht wire you get more S because turns accommodates closer each other, as the dielectric permitivitty of silk and nylon is similar to the wire enamel, the lack of air between turns also increases ε, as a result, the capacitance would remain almost the same.
A proper winding also has insulation between layers, then the difference in capacitance would be negligible.
Even on the worst case scenario, with both wires a proper interleaving will make self capacitance negligible and distributed capacitance can be made almost identical as a design choice.
Conclusion: Do not waste your money in expensive Litzendraht wire, there are other expensive things like NOMEX that will be more effective in reducing capacitance.
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Yes. And as the result it (decreasing losses) increases Q creating in audio more problems (contrary to radio, where it solves problems) ;-)
Non-litz wire also is available in silk insulation, if you want to compare apples to apples.
Yes, I took this advantage and I myself convinced that litz wire really works in RF in my High Audio Quality AM Tuner. From the RF amplifier made with standard copper wire, to litz recovered from fluorescent electronic ballast, there was an improvement of near 20dB (100 times) same turns, same core, same tunning capacitance, same tubes. But at audio frequency appears to be unnecessary.
Added to the fact that Litzendraht wire increases winding resistance and hence also does distortion, we can conclude that it is a bad idea.
A very expensive one... 😛😀
It depends. If you have a large quantity of reels of litz wire stores from decades ago when the radios had IFT tuned transformer in 5cm * 5cm cans, and then you want to sale "Audio grade audio transformers", perhaps it's a good idea to use them to "engañar giles" (To fool fools).
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