[SOLVED] Transformer Lamination

[Manojcheers]

Dear Sir.


How to model our own lamination dimention (i.e) Dimentions of the each leg (Height , width ..etc) of a three phase iron core EI Laminations


Kindly refer me any book or articles behind the geometry calaculation



Regards
Manoj

 

[c_mitra]

Usually these parameters are not under user control; we select the size based on our need of power and frequency. For 50Hz power transformers, the required stampings are not (I believe) custom made.

 

[Manojcheers]

Dear sir,

i used to pick the core based on Core geometry for transformers and Area product approach for the Inductors .

Im trying to model a two inductors On a single core with different inductors value .So will be better if i know the geometrical calculation behind the sizing the dimentions of EI core.

Best regards
Manoj

 

[schmitt trigger]

On EI laminations, the design is based on the scrap-less approach. In other words, during the punching out of the lamination, the "E"s window area become the "I"s.

Another consideration is that the center leg is twice as wide as the outer legs to maintain the flux density.

 

[Manojcheers]

Dear sir,

I used to find the core area say 40cm^2 which is splitted into lamination * Stack .As per the data sheet i will choose lamination *Stack = 2.1*0.96 cm and the stack sizes varies based on the power and the core area varies depends on the powe handling ability of the core .

I wanted know the design procedure of laminations that is sizing the dimentions .Kindly let me know the dimention sizing procedure of the lamination

Regards
Manoj

 

[andre_luis]

The sizing procedure of the laminated transformer does not only take into account the handled power but also other factors such as the waveform and the frequency of the applied signal, which in a way implies defining the topology where it will be applied, and in this way it is possible to find very explanatory tutorials about this on the web.

 

[Manojcheers]

Dear sir,

My question is not about sizing the core area of the transformers and reactors. Its about Dimention for eg : How the data sheet of Ei core with differnt dimention like width, height ,length of the toungue Window areaand its entry geometry on what factor these paramaters are prepared .I would like to know the background of this . Kindly Send me any topic regarding this Awaiting for the positive reply.


Best regards
Manoj

 

[smijesh]

1. Why different size of lamination (Your question)
Ans: Depends on the power handling capacity (Small size lamination can handle small power and big size lamination can handle more power. because you cant increase cross sectional area in small lamination core by staking more and more lamination
It will increase winding loss . Thump rule is that the winding loss and core loss should be same)
2. Different dimension like width, height ,length of the tongue Window ????
Ans: For eg: single phase lamination core having more width on the center leg than other two side legs because we are winding on the center leg only the flux traveling center leg to each other legs so more flux traveling from center leg. Avoiding saturation due to more flux on the center leg, we are normally increasing the width of the center leg

 

[Manojcheers]

Dear sir,

You are not getting my question ,Kindly try to understand

1.) How should i design my own core dimentions.

2.) I have only Power Rating (VA/ Kva ), Insatead of selecting the core dimentions ( width , height ,length ,A,B,C,D...etc) from data sheet i want to design the EI Laminations of my own

3.) I have to draw the core dimentions by myself without the core size selection chart.

Awaiting for your reply

Best regards
Manoj

 

[smijesh]

Dear Mr. Manoj,
Please find the reply

1.) How should i design my own core dimensions.
Ans: Up on your experience !!!!!!!!!!!!. There is no essay formula for designing core dimension, you can select E shape geometry lamination and select dimension for total length, total width, center leg width side leg width window width and window length.Keep in mind the center leg width should be double to each side leg width.
Magnetic path length,cross sectional area,window area are major design parameter for transformer design.

2.) I have only Power Rating (VA/ Kva ), Insatead of selecting the core dimentions ( width , height ,length ,A,B,C,D...etc) from data sheet i want to design the EI Laminations of my own

Ans: Design lamination core as per above method(#1) and calculate turns and other parameters, if your core loss and copper loss are almost same then you can say that your core design is ok otherwise change the each dimension of the core and recalculate losses repeat the exercise.....

3.) I have to draw the core dimensions by myself without the core size selection chart.

Ans: You can draw your own core dimension as per #1 & #2 Keep in mid that the magnetic flux should travel through the core as per image on post #8.

 

[Manojcheers]

Dear sir,

Thanks for your reply .So, reverse engineering is the only option !!!!


Best regards
Manoj

 

[andre_luis]

So, reverse engineering is the only option !!!!

I would not call this by reverse engineering, but rather as essays for obtaining a closed mathematical model or calculation procedure based on each material for each manufacturer. Sinccerelly this sounds like a waste of effort, due you certainly will not take something much more simple that it is currently available.

 

[Manojcheers]

Dear sir,

I would like to design a 2 inductors of different inductance and current value so i though of knowing the backgroun .


my project involves 2 - EI lamination of same size and core area but differnt inductance and current .Which is placed one above the other in the form of E-I -E-I

Best regards
Manoj

 

[andre_luis]

Which is placed one above the other in the form of E-I -E-I

Now the question became a bit more confusing, mainly because you do not provide enough details.

Are these cores magnetically coupled ?
What matters if they are made with different materials ?

Did you follow any online tutorial covering the step-by-step procedures on designing transformers/inductors ?

 

[Manojcheers]

Dear sir,

Im trying to design a LCL Filter inductor model consisting of two seperate cores are magnetically coupled

this is more complicated because the inductance of the inductors are different and the current is different .

I have to maintain the core of both the inductors to be same and the core height is adjusted .

This is why i tried to find out the background of the core dimention construction.

Best regards
Manoj

 

[andre_luis]

Im trying to design a LCL Filter inductor model consisting of two seperate cores are magnetically coupled

It took 15 posts until you mentioned this topology for the first time. Moreover, if you want to magnetically couple them, why not doing that with the same core ? On other hand, being the winding at different cores, how do physically do you plan to couple them ? EI cores have their flux magnetically enclosed within itself. Is there any other information you did not provide yet ?

 

[Manojcheers]

Dear sir,

Will introduce a airgap inorder to maintain the inductance value .

best regards
Manoj

 

[FvM]

Calculation of arbitrary magnetic circuits with air gaps and complex core geometry is described in this article "Deriving the Equivalent Electrical Circuit from the Magnetic Device Physical Properties", 1994 Lloyd Dixon
https://www.ti.com/seclit/ml/slup198/slup198.pdf or
https://www.edaboard.com/threads/293560/#post1258727

 

[Manojcheers]

Dear sir,

• B =Uo * Ur * H (T)
• R = lc/(uc *Ac)
• R airgap =lg/(uo*Ag)
• Total NI (mmf) =(Hc*Lc) +(Hg*Lg)
• Bc =(Fc/Ac)
• Bg =(Fg/Ag)

This are the parameters and formulas for the Ac inductor (Magnetic Model)

Why should i use this magnetic model to verify my model ???

Best regards
Manoj

 

[schmitt trigger]

One way you should do it to make it easier to calculate is to simplify the equations.

For instance, since the air gap reluctance is much higher than that of the core, a common simplification is to assume that the total reluctance is essentially that of the air gap.
R total ~lg/(uo*Ag)

The error will be small. And as others have already mentioned, fringe fields introduce a larger error anyways, which can by adjusted by the number of turns.