diyAudio (
-   Solid State (
-   -   Etd 49 & 3c90 Help!! (

GEORGE HO 19th May 2004 03:33 PM

Etd 49 & 3c90 Help!!
Anyone help,I have E core 3c90 ETD49,so how many watt power supply i can made and which frequency more effective,input
240ac & output +/-130vdc.

Jaka Racman 19th May 2004 06:12 PM


Do not try to build offline smps if that is your first project and you do not have access to isolation transformer and oscilloscope. It can have lethal consequences. Use this link page 21 to calculate power capacity of your core. Do not forget to factor in proper isolation between primary and secondary (minimum three layers of insulation and 8mm creepage distance).

Best regards,

Jaka Racman

Eva 20th May 2004 11:39 AM

This thread may contain useful tips :

I recommend low voltage SMPS experimentation to grow some experience and knowledge before trying to handle high voltages. Oscilloscope >=20Mhz with >1KV internally attenuated probes, mains isolation transformers and step-down transformers are almost mandatory. Also, it's not a great idea to test prototypes with 300V DC the first time you run it, I use 50V-100V in series with a light-bulb or even 24V regulated and current-limited for that purpose, and when everything appears to work right I increase the supply voltage. Never test anything with 320V [230V rectified] before succesful testing with lower voltages or without a reasonable size fuse in series

FlyingDutchMan 20th May 2004 12:03 PM

The ETD49 with a 3c90 core is quite a big core. the 3c90 material should be run between 20kHz and 200kHz. I'm unsure as to the maximum flux density (or what ever it is called), but you should be able to get >300W thru it at 20kHz. I've currently got some effiency issues with one I'm bulding at the moment (same former and material), so I can't really tell you what you can do. I'm getting about 150W out for 250W in :xeye:. 60% effiency - Not good.

GEORGE HO 20th May 2004 03:01 PM

Hi FlyingDutchMan

can you post your project schematic, how you made your power
supply,which controller is used on the circuit.


FlyingDutchMan 21st May 2004 12:39 PM

Heres the schematic. And yes befroe you get shocked that is a 555 controlling it - there is no feed back at all.

The # of windings is 4 for each primary and 11 for each secondary. It runs at about 75% duty cycle - when both the 3rd and 5th harmonics are at a equally low point.

GEORGE HO 19th June 2004 11:44 AM


Any one know what is difference between offline or online smps,it I
use self oscillation ir2153 resonant converter,it is offline or online smps.

George Ho :confused:

Eva 19th June 2004 02:27 PM

Altough english is not my mother language, I think the term 'offline SMPS' designates any SMPS circuit whose primary side is directly connected to mains line [probably from 'power taken off the line']

I don't know of any references to 'online SMPS'

ChocoHolic 19th June 2004 06:28 PM

...UHPS!! I thought the other way round...?
I was thinking that offline SMPS are not directly connected to the mains, because the "off" is written with "ff" not "f".
I interpreted it the same way as I am used from the WEB, and thought offline would mean not connected.
:xeye: :xeye:
i.e. car smps or sm-regulators behind a regular isolated transformer...


No matter how it is called....
The thing which you are planning seems to be the more difficult and more dangerous sort of smps. If I understood your first post correct,
you are planning t as you are going to deal with the full non isolated mains voltage...
And also your output voltage is quite high!
Do you need this for tubes, or are you going to supply a high power class D halfbridge amp?? Just curious.

Also the IR2153 is not directly implicating a certain topology of your smps. But it does not lead my thoughts to a standard single ended forward converter or a push pull topology....
Also curious in this regard ..;)

Bye and by careful

Pafi 19th June 2004 10:41 PM


I've just finished a 230AC/2*100VDC SMPS with ETD44. For a short time (some minutes) it delivers 2000W. Time is not limited by transformator, but the heat sink on semiconductors. But: the proper winding of a SMPS transformator is not easy! If the coupling is not perfect, it will produce very much heat! Current is limited by series inductance, and a fuse. Operating frequency is 50 kHz. At higher freq the core can handle more power (again: with proper winding), but switching losses increasing on transistors.

This is strange. IR didn't specify output current on IR2153!

Here is my SMPS:

All times are GMT. The time now is 11:34 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 18.75%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio