How to read permeability graphs of EI lamination

[xazrules]

Hi someone can help understand the graph that a company that sells EI lamination sent to me for their lams?
I’d like to extrapolate a gauss value from these graphs for my calculator.
Here’s the link:

https://www.italtras.us/img/Curve_Perdita_W2_3_Spessore_0_5mm.JPG

https://www.italtras.us/img/Curve_Perdita_GO_M6_Spessore_0_35mm.JPG

The last one is for a grain oriented M6.
Thank you

 

[guitarmike2107]

Hey X, those graphs show the losses W/kg

Check out this sheet, on the first two graphs showing Magnet field strength and Magnetising current you can clearly see the knee in the curve, You want to design your transformers on the linear sections below the knee (the straight section below the bend in the curve)

https://www.mediafire.com/file/1vwznjojrzx94zz/400-50+Spec+Bundle.pdf/file
So I use 1.1T max for this material ,but I have seen other designers use it to 1.4T - and ended up with noisy hot power transformers

 

[xazrules]

thank you very much guitar mike! very appreciated, so 1.1T are 11000 gauss right?

 

[xazrules]

i need to fix an input transformer, it has EI48 lams M6 grain oriented, the lams weight about 200grams.
i've bought a calculator for winidng transformer and you need to specify the gauss of the lams to know how many turns to do for a specific pri sec ratio

 

[guitarmike2107]

Hi X, for M6 I use 1.4T or 14000 Gauss, For M400 or lower grade lams that are typically 0.5mm thick, I have had good results using 1.07T or 10700 Gauss.

 

[xazrules]

Exactly the answer that i was looking for! thank again guitar.
last question, is it always preferable to invest in better lams and using less turns?

 

[KIDVOX]

for simple stuff i use simple apps on my mobile; Z transformers. and TransCalc. both are free and give a good pointer. im sure many here could go into the sciance and maths involved but i aint an electronics expert.

 

[guitarmike2107]

No, I don't think it is always preferable at all, depends on the application and what the end user wants out of the transformer.

 

[Chandra]

Exactly the answer that i was looking for! thank again guitar.
last question, is it always preferable to invest in better lams and using less turns?

The formulae for turns per volt N = 10^8/(4.44*F*A*B*V)
F=Frequency (50 or 60), A=area in Sq cm, B=Flux density (11,000-15,000 lines per Sq cm per core selected), N=Number of turns, V=Voltage =1 for t/p/v.
For audio, go for the minimum frequency required and use thinner lamination.
To get most out of the transformer, fill it full with copper, select proper wire sizes.
Allocate equal area for Primary and Secondary windings.

Regards.

 

[xazrules]

Thank you!!

 

[ricardo]

is it always preferable to invest in better lams and using less turns?

Better laminations & less turns will give you the same performance with a smaller unit.

Dunno about today, but in da old days, a good transformer maker could provide a cheaper unit by doing this.

 

[xazrules]

I can buy M6 grain oriented lams for 10 euros per kg.
I’ve disassembled an edcor 10k:600 and weighted the lams EI48, they’re about 200g.
Have you ever managed to weight the copper needed for a specific trafo?
Because i don’t know how much enamel to order.
And another thing from the same supplier i’d like to order the bobbin, but for EI48 they only have ones with
a center flange, the only one without the center flange is for EI60.
For audio is it good to wire turns of pri and sec in parallel? Or the only method is to interleave them one over the other? Thank you
I post linka of the bobbins.

https://www.italtras.us/ei-48-colonna-16/346-rocchetto-16x20-z6dg.html
https://www.italtras.us/ei-60-colon...dg-senza-flangia-pins-inseriti-con-asole.html

 

[volker]

Have you ever managed to weight the copper needed for a specific trafo?

You can easily calculate it to get a rough estimate. For a EI48 the average turn length will be about 9cm.

And another thing from the same supplier i’d like to order the bobbin, but for EI48 they only have ones with
a center flange, the only one without the center flange is for EI60.

Unless you're going to build them in big numbers, just cut the middle part out, no problem.

For audio is it good to wire turns of pri and sec in parallel? Or the only method is to interleave them one over the other? Thank you
I post linka of the bobbins.

That depends on the circumstances. High or low impedance, ratio, .... difficult to come up with general rules.

 

[gyraf]

For audio is it good to wire turns of pri and sec in parallel? Or the only method is to interleave them one over the other?

This is the whole art imo.

Look up CJ's dissections around here - there's lots to learn from..

/Jakob E.

 

[xazrules]

Looks like I have something to keep my head busy for the coming winter.

“an idle mind is fertile ground for the devil”