EI transformers vs Toroidal transformers

[Viktor277]

I was wondering which type of transformer is better, since i cant find legit answer on the internet. They just say that toroidal transformer is more efficient.

And is there more types of transformers out there? Which one is the best?

[mariushm]

There's even better types ... for example the R-core: http://jamestransformer.com/en/transformer/R_core_transformer.html

They're more expensive due to manufacturing costs ... but have benefits like super high insulation between primary and secondary (as they're separate spools)

 

Toroidal should be a bit better than EL as the magnetic fields are concentrated inside the t. footprint and leak less and can be easier to shield rest of circuit. Also lighter since no steel duh...

A downside is much higher "inrush" current, when you connect primary winding... may have to make a soft-start circuit ( add a PTC/NTC/resistors that optionally are removed from circuit using a relay or something else)

 

Here's a good forum thread with pros and cons: https://forum.audiogon.com/discussions/toroidal-vs-non-toroidal-transformers

 

[Viktor277]

On 4/28/2019 at 12:19 PM, mariushm said:

There's even better types ... for example the R-core: http://jamestransformer.com/en/transformer/R_core_transformer.html

They're more expensive due to manufacturing costs ... but have benefits like super high insulation between primary and secondary (as they're separate spools)

 

Toroidal should be a bit better than EL as the magnetic fields are concentrated inside the t. footprint and leak less and can be easier to shield rest of circuit. Also lighter since no steel duh...

A downside is much higher "inrush" current, when you connect primary winding... may have to make a soft-start circuit ( add a PTC/NTC/resistors that optionally are removed from circuit using a relay or something else)

 

Here's a good forum thread with pros and cons: https://forum.audiogon.com/discussions/toroidal-vs-non-toroidal-transformers

 

Thanks, but which type of transformer is this? Cant quite figure out.

[mariushm]

It's classic EI type transformer ... you have E shaped steel plates on one side and I bars on other side interleaved to form the EI shape. You can see the four screws which tighten all the steel plates.

 

For extra shielding, to minimize magnetic field and capacitance there's a copper foil wrapped around the exterior of windings and in theory it should be connected to ground, sometimes through a resistor.

That's why it may look a bit strange to you.