it can be closed because nobody give the measurements i asked for and 45 is still talking rubbish.
Come on guys, both of you has made excellent transformers, even better than renowned brands, think about people that can be gifted from your designs.
If you still fighting, moderators will close this thread, and people won't can learn anymore.
esltransformer everytime you have to come out judging the others when you have no arguments. This is typical of people who don't know and it is certainly your case EVERY TIME. It's a fact.
If you just left aside certain arbitrary comparisons just because your only aim was to show off I wouldn't ever bother to respond. The problem is that you are not in the position to make comparisons. You already make mistakes at design level which firstly means you also are not in the position to judge someone else transformer.
At this point no measurements are actually needed if you want to know where you are. You can HONESTLY and PROPERLY measure your transformer as see if your specs are all true (they aren't!) and how they compare to those of the FC-30 that are of public domain!
If you want to see mines you have to wait. This thing has become quite boring now.
Quod erat demonstrandum
Sorry to say that, but so far you have not demonstrated anything, your transformer data are so confused, e.g. your core on post#3 was EI 150/70, then reduced to EI 120/50 on post#111, then reduced even more to EI 120/40 on post#114.
Unlike us, you have not posted neither the number of primary turns, so you can criticize our designs but yours are untouchable...
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Your model is totally wrong, sorry to say that your vision of real world is very naive, in real world transformers, capacitance is a nightmare to calculate, so a more complex model is needed.
For a transformer with grounded short circuited secondaries, interwinding capacitance is distributed as
Ce ≈ C ∑ (nı/N)² ı=1,...,m
Suppose now that secondaries are left floating, then
Ce ≈ C ∑ [(2nı-N)/2N]² ı=1,...,m
Now we must consider capacitance of each primary winding
Cwı = (4/3nı) [1 - (1/nı)] Clı ı=1,...,NP
Where Clı is the capacitance between two adjacent layers, then total winding capacitance
(Cw)⁻¹ = ∑ {(4/3nı) [1 - (1/nı)] Clı}⁻¹ ı=1,...,NP
If we take Cl as the average interlayer capacitance
(Cw)⁻¹ ≈ (Cl)⁻¹ ∑ {(4/3nı) [1 - (1/nı)]}⁻¹ ı=1,...,NP
Also
C = (ε A) / (4πd)
Cl = (εl A) / (4πdl)
For properly made transformers as I do, need at least 0.4mm to 0.56mm insulation between windings of NOMEX 410 (ε=1.6) and 0.05mm polyester with epoxy (ε=4.4) between layers, then say d=0.5mm and dl=0.01mm (0.05mm polyesrter and wire coat) we obtain
Cl ≈ 13.75 C
Given that high leakage inductance of transformers from your link, I strongly suspect that manufacturer lowers capacitance with a more simple winding pattern as 2P-S-4P-S-4P-S-2P, without any vertical sectioning, then
Ce ≈ 1.44 C (grounded secondaries)
Ce ≈ 0.36 C (floating secondaries)
Cw ≈ 0.98 C
Then, for grounded secondaries
CTg = Ce + Cw ≈ 2.42 C
For floating secondaries
CTf = Ce + Cw ≈ 1.34 C
Et voilà
CTg / CTf ≈ 1.8
This result match reasonably well with most of tranformers from your link: S-5 845 (1.78), S-7 211 (1.79), S-9 300B (1.72), S-15 GM70 (1.99), S-17 PSE 211 (2.06), S-19 PSE 300B (1.78), S-25 LP 845 (1.97), except for model S-833 (2.85), but this works with 2KV!
We need a different winding pattern, say 5P-S-10P-S-5P, more insulation, say 1mm Mylar between windings and 0.1mm Mylar between layers, also triple insulated magnet wire, so
Cl ≈ 5.5 C
Then
Ce ≈ 1.25 C (grounded secondaries)
Ce ≈ 0.25 C (floating secondaries)
Cw ≈ 0.31 C
Then, for grounded secondaries
CTg = Ce + Cw ≈ 1.56 C
For floating secondaries
CTf = Ce + Cw ≈ 0.56 C
Et voilà
CTg / CTf ≈ 2.78
Very close ah ?
BTW. The open poster OPT has far better specs and frequency plot than those from your link.
As you can see, this is not alchemy, it is necessary to pose equations and sweat!
Every winding pattern, every insulation pattern and every insulation material will change the results, things are not that easy as you think.
P.S. You can measure Ciw with reasonable accuracy, with a capacimeter between P and S, so
C ≈ Ciw/m
Oh no!!! Again with that...how did you said?
I did explained you twice...
As I showed before, your model is wrong, shunt capacitance doesn't depends on oil prices, between certain limits you can choose it by design, and that chosen capacitance doesn't change because at every time t, you have a simple electrostatic problem, and (+U)+(-U)=0, regardless of grounded or floating secondaries.
What university had the courage to grant you a PhD?
Maybe that's time to change your model, maybe your transformers would has a better frequency response...
67KHz is very poor, even for most Monolith Magnetics standards...
Duh!
Yeah, you are right. One doesn't drink and the other thinks to be a master without having done anything for real....
time to rest guys....- Status
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