Transformer core laminations Eddy current 3

[Mr zezo]

Where does the Eddy current induced in transformer core laminations? Means in which area, suppose rectangle lamination with length L ,width W and thickness X,? and why? And what's the angle between main magnetic field and the core laminations is it parallel to it or Perpendicular ، then how it cut the laminations to induce Eddy current? and does the insulated surface is subjected to induced Eddy current also?

 

[waross]

The eddy currents are induced across the thickness of the laminations. That is why laminations are used and are insulated from each other.
Look at it another way, the direction of the eddy currents is interrupted by the insulation between the laminations.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[unclebob]

https://www.magcraft.com/blog/what-are-eddy-currents

I wanted to see for myself.

 

[7anoter4]

See:

https://nptel.ac.in/content/storage2/courses/108105053/pdf/L-22(TB)(ET) ((EE)NPTEL).pdf

 

[prc]

Thank you 7anoter4 for that link.

 

[Mr zezo]

Thanks for that link 7anoter4 , but he assum that the flux is perpendicular to the the area h and thickness ,then in transformer does the magnetic field is perpendicular to the laminations thickness,how? it seems like it is parallel to the laminations

 

[prc]

What is shown is the cross-section of the lamination. h is the width of lamination. In transformer flux is moving parallel to lamination ,but through the cross section of the lamination.

 

[7anoter4]

The useful magnetic field passes perpendicularly through the magnetic sheet but the leakage field flows parallel

 

[prc]

7anoter4.Let me explain. The leakage flux that you showed will be almost nil with one single winding because of the negligible magnetizing current in the winding. But when the secondary is loaded, opposing currents flow in windings and a fairly strong leakage flux develops between windings(still maximum flux density in the gap between windings will be only 0.05- 0.2 T compared to 1.7 T in the core. This leakage flux moving up between windings, some distance away from core surface (in core type construction) enters the core yokes or limbs, depending on the direction of flow of power (from LV to HV or HV to LV) This can add up with main flux in core in the yoke or limb. Designers of large transformers take care of this aspect to avoid magnetic saturation in core.

 

[7anoter4]

Thank you, very much ,prc.

 

[Mr zezo]

Thanks for all your responses , but if the magnetic flux is moving through (inside)the core then how it cut or linkages with secondary windings to induce the emf? Sorry for my confusion.i hope if there is any simulation or animation which clear all confusions.