smps transformer

[nigelwright7557]

If you try to push too many amps through the primary it will saturate and the current will shoot up.
A way around this is to gap the transformer. I found a 1mm gap works well.

 

[panos1]

guys how do i calculate the thiknes of the wire at the primary?

 

[palstanturhin]

The easy way...

1st rule:
Use all available window area you have. Apply also the isolation between the primary and the secondary and deduct that from your available core window. You now have the winding window area.

2nd rule:
Reserve from the available winding window area about 45% for the primary and the rest for the secondaries...

3rd rule:
Use max. 0.5mm dia wire / thick foil. (will cover frequencies up to 55-60kHz)


How many parallel wires did you get when you did the math according to the above???
To the primary?
To the secondaries?


Someone else can introduce the "hard way", with permeabilities and skin depths and stuff...

 

[johansen]

If you try to push too many amps through the primary it will saturate and the current will shoot up.
A way around this is to gap the transformer. I found a 1mm gap works well.

this is only true for flyback and forward topologies, because energy is stored in the transformer core, which has a gap for the purpose of storing the energy in the air gap.

for various other resonant topologies, and other non resonant which store energy in the output inductor, or input inductor, there is no energy stored in the transformer and it will not saturate under increased loading.