Electronics > Projects, Designs, and Technical Stuff
ATX Flyback Transformer
engrguy42:
I'm stumped. Pulled a flyback transformer from an ATX power supply, and for the life of me I can't figure out how it's configured. No markings on any of the pins, and only a "Delta" label on top, which is the OEM brand of the power supply. But I assume it's a special made for Delta cuz I can't find ANY spec sheets or references whatsoever. It looks to me like a Wurth with that yellow-ish tape around it.
The ATX supply provides 12, 5.5, and 3VDC. As you can see from the image, the right side is the primary (with an unconnected center tap). (BTW, I soldered those wires for testing. The xfmr is normally mounted on the PCB). I think the secondaries on the left represent only two windings even though there are 6 pins, since if you look close you can see a couple sets of pins are soldered together. So I'm guessing the secondaries are like a 12VDC plus an aux. winding.
I applied a signal (sine wave) on the primary and get basically zilch on the secondaries. But I'm clueless about flybacks, so I'm not sure what I should get. It's just a transformer with the windings on a common core, right? Anyway, I especially want to figure out the polarities and ratios, but with nothing on the secondary I'm stumped how to figure that out.
Anyone??
engrguy42:
Nevermind...
I dunno, cockpit error or something. Got some nice clean sine waves on the secondaries now. The ratio for both windings is is 12.5:1, and I've got the polarities sorted by superimposing primary and secondary voltages on the scopely. |O
engrguy42:
Ahhh...okay. The cockpit error was that it doesn't like low frequencies. I had the waveform generator set for like 60Hz, but you need to get up past around 1kHz to get anything out of the secondary.
I imagine that will make sense if I think about it a lot... :D
wraper:
It's not even a flyback transformer. PSU most likely uses forward or some type of bridge topology.
--- Quote ---Wurth with that yellow-ish tape around it.
--- End quote ---
Vast majority of SMPS transformers use yellow tape. And there is 99.9% chance it's a custom part.
NiHaoMike:
Some small ATX PSUs (less than 150W) use the flyback topology.
Navigation
[0] Message Index
[#] Next page
Go to full version