Powersuply mystery

[argo]

I have one trafo with two secondary windings feeding four rectifier bridges for two symmetrical regulated powersupplies like shown in sketch below. Something is wrong with this circuit because it trips the main fuses of any value. I also tried bare wire soldered across the fuse for a second (WARING- don’t try that at home) and seems like there’s a short circuit somewhere because tranny and bridges got really hot during that. Only thing I can figure out is maybe short in the capacitors. But the caps were fine before applying power. So I am clueless. Can somebody figure out what is wrong here?



Thanks in advance

Argo

[moamps]

Originally posted by argo
......Can somebody figure out what is wrong here?....

Hi,
secondaries are shortened with two serial two antiparallel diodes thru ground.
Two bridges for same supply must be supply from same secondary. For example, B1 and B3 from S2, and B2 and B4 from S1.

Regards

[argo]

Oh yeah, I must have been blind I just draw the sketch only after I wired the circuit. I wired it like this because it was more convenient (shorter wires, less mess). Very stupid of me .
I should have drawn the circuit before wiring and give a second or two of thought rather than second or two of shortened secondaries .
Thanks a bunch for pointing out this error

Argo

[moamps]

Hi,

Also, this PS setup isn't optimal, IMHO.
A better setup is with CT secondary and single bridge for each +/- PS.

Regards

[argo]

Why this setup isn not optimal?
I wold agree two trannys instead one would be much better. This is my final goal but did'nt had two of them at hand so I tried with one at first.

[moamps]

Originally posted by argo
Why this setup isn not optimal?

Hi,

draw bridges like 4 diodes. Than you will find that you have parallel diodes pairs from different bridges thru the ground point. If those diodes haven't perfectly same V-I characteristic some current will flow thru ground connections from first to second PS and vice versa. This isn't good.

Regards

[argo]

Originally posted by moamps

Hi,

draw bridges like 4 diodes. Than you will find that you have parallel diodes pairs from different bridges thru the ground point. If those diodes haven't perfectly same V-I characteristic some current will flow thru ground connections from first to second PS and vice versa. This isn't good.

Regards

I see . Good point
Thanks.

Argo