[SOLVED] Skin dept versus maximum wire diameter in Smps transformers

[Salvu]

I am a bit confused what is the maximum ECW diameter versus skin dept

For example if according to the frequency of operation the maximum skin dept is 0.5mm

1) What will be the maximum diameter of ECW can be used is it 0.5mm or 1mm?

2) If I have to twist a bundle of 4 wires will the overall bundle diameter be considered as maximum diameter?

3) What will give the best coupling in ferrite transformer winding, twisted wires or wires side by side?

Any help will be greatly appriciated

Regards Salvu

 

[smijesh]

1) What will be the maximum diameter of ECW can be used is it 0.5mm or 1mm?
ANS: 1mm by theory, but less than 1 with multiple wire will reduce both AC and DC resistance of the enameled copper wire

2) If I have to twist a bundle of 4 wires will the overall bundle diameter be considered as maximum diameter?
ANS: Select lowest wire diameter as per skin depth calculator find out cross sectional area of the wire then divided by required area (As per current ratting) then you will get how many strands require

3) What will give the best coupling in ferrite transformer winding, twisted wires or wires side by side?
ANS: Twisted wire

 

[FvM]

Ideal conductor diameter dx2

It depends. In coil geometries where the current flow is pushed to one side of the conductor due to proximity effect, dx2 can still involve a noticeable AC resistance increase.

Strands of enameled wire are a means to reduce skin effect. Proximity effect does still occur, wire diameter should be <dx1.

 

[Salvu]

Thank you very much for your help.
one last question to make things more clear please.
When using Excellent IT software. According to the skin dept shown on the software mean that I can double the diameter is that correct?

Regards, Salvu

 

[Salvu]

Thank you FVM. Keeping diameters less than the maximum helps for less losses in AC resistance