ER33c / EI 33 / ETD 34

[horizonrays]

hello friends ,
well in this post i seek help regarding half bridge smps .
I have salvaged some er33c cores .and i cannot find anything regarding them on the net
all i can find is ei 33 core , but my core does not look like them ,
it look more like etd 34 core .

primary turns are around 36-40 , not exactly sure , how many i forgot , how many turns were there !!

but they were around these numbers .


so any one would like to help me design a smps transformer , for 12v output and 5 volts out put ?

considering the max vin 265v rom ,
and minimum is 180 v rms .

thank you .

.

 

[Dimonis]

Hi!
Maybe it's a EER35 core?
Look in this sheet.

 

[horizonrays]

it's not eer35 .

by design it looks like edt34

 

[Dimonis]

it's not eer35 .

by design it looks like edt34

And what's the great difference between ETD34 & EER35 ?

 

[Dimonis]

You can take about 330W at 50kHz of it.
Primary 40 turns , sec 5+5 (12V) , 3+3 (5V)
P.S. Sorry , this program is only in russian.

 

[horizonrays]

And what's the great difference between ETD34 & EER35 ?

difference or not this is the core i have , have a look .
that being said .

According to fexocube datasheet , EER 35 can give 325w @ 100Khz .
and edt can give 271 w @ 100 Khz .
there is a bit difference in core section area and AL value .

and problem is that , i salvaged the core from smps , i can only speculate the values . As Transformer was marked as ER33C , and i cannot find any core with such name .:"::

by the way you used er core , can you use edt 34 core and recalculate the values ?

thanks for helping .

 

[Dimonis]

Can you measure the dimensions of your core?
ETD34 - 47turns 6+6 3+3
262W at 50kHz

 

[horizonrays]

have a look at the core and it's dimensions ,


thanks again .

are you sure , that at 50Khz this core can give 250+ watts ?
i thought it needs 100Khz for the same .

 

[norazmi]

50 Khz maybe can but with tight winding, up freq to 80 Khz or even 100 Khz will do

 

[Dimonis]

262W at 50kHz

Sorry 225W
And 290 at 100kHz