Quote:
Originally Posted by Paul D. Spiegel
For my next project I have acquired a transformer with two identical 450v
secondary windings. I could put the windings in parallel and use a bridge
rectifier. Or, I could put the windings in series and ground the coupling
for a 450-0-450 configuration to use with a pair of diodes.
Which would you do? What are the pro's and con's of the two
configuration?
For this project I am using SS rectifiers. Were I using a tube rectifier
I would go with the center tap, of course.
- Paul
|
Hey Paul, I think I may have corresponded with you a few years ago with regard to my take on Crowhurst's Twin Coupled Amp. Was that you?
Anyway, here is my take on the FWB as opposed to the FWCT systems. An important consideration for PS designers is something called 'Utility Factor' of the various windings on the PT. Others have already noted the FWB to be better if that connexion is possible. I've attched a numerical example here for the secondary winding UF for the FWB with cap input filter. Since there are no other windings the primary & secondary UF's are equal.
Other examples will follow but in following posts since file size is limited here in AudioBanter. But in summary the best UF for single phase work is the FWB with choke input to fillter. The lost power during the conversion from AC to DC is in the form of the even order harmonics (2nd, 4th, 6th...Etc) generated by the rectifying process.
You could check for the possiblity of circulating currents in the parallel connexion of your PT secondaries as follows. Connect one end of the secondaries in series opposition. Then with an AC VM check for any voltage differance.
My guess is the voltages are near equal but with somewhat different resistance, all OK to parallel permanently. Sounds like you have a PT built from the core up to be series or paralleled, commonly available. For example, Hammond lists many such devices.
Cheers to all, John