how to model 125-0-125 in PSUD

cbutterworth · 3rd November 2006, 03:22 PM

This may be really dumb of me, but either way, I'll learn....

I am trying to model a full-wave bridge rectified PSU using the Hammond 269AX transformer. The specs are 125-0-125 at 100mA. I was recommended to use this ina PSU that would give around 340V at B+.

Now, when I try to model this in PSUDII, I am unsure how to enter to transformer's details. If I enter 125VAC at 100mA, I do not get 340V DC at B+. However, if I double the 125 to give 250VAC at 100mA, I do get around 340V at B+. The design says not to use the center tap.

So, should I add both sides of the transformer to give 250VAC in PSUDII?

Thanks,
Charlie

Bakmeel · 3rd November 2006, 03:41 PM

That's right!

If you don't use the center tap, you actually get a single transformer tap with the two tap voltages added together. The rectified voltage you get is 250V * SQRT(2) = 353.55, minus some regulation and rectifier losses gets you around 340VDC.

You're on the right track.

Bakmeel

cbutterworth · 3rd November 2006, 03:47 PM

Great.....that's what I thought, Phew!

Thanks,
Charlie

3rd November 2006, 03:22 PM	#1
cbutterworth diyAudio Member Join Date: Oct 2006	how to model 125-0-125 in PSUD This may be really dumb of me, but either way, I'll learn.... I am trying to model a full-wave bridge rectified PSU using the Hammond 269AX transformer. The specs are 125-0-125 at 100mA. I was recommended to use this ina PSU that would give around 340V at B+. Now, when I try to model this in PSUDII, I am unsure how to enter to transformer's details. If I enter 125VAC at 100mA, I do not get 340V DC at B+. However, if I double the 125 to give 250VAC at 100mA, I do get around 340V at B+. The design says not to use the center tap. So, should I add both sides of the transformer to give 250VAC in PSUDII? Thanks, Charlie

3rd November 2006, 03:41 PM	#2
Bakmeel diyAudio Member Join Date: Jan 2002 Location: The Netherlands	That's right! If you don't use the center tap, you actually get a single transformer tap with the two tap voltages added together. The rectified voltage you get is 250V * SQRT(2) = 353.55, minus some regulation and rectifier losses gets you around 340VDC. You're on the right track. Bakmeel __________________ More Power Igor! More Power!

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3rd November 2006, 03:47 PM	#3
cbutterworth diyAudio Member Join Date: Oct 2006	Great.....that's what I thought, Phew! Thanks, Charlie

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