24/48 power supply? will this work?

[Tekay]

Why complicate it more than you need? If you have two separate 30V AC windings, built two identical 24V circuits with a rectifier, cap and a regulator.
Put the negative from circuit one to ground, connect positive from circuit one to negative on circuit two. You will now have +24V DC from the positive output of circuit one and 48 V from the positive of circuit two. Just like two batteries in serie!

 

[imloggedin]

You sir, are correct. I didnt know you could do that without smoothing the negative. Thank you very much.

 

[PRR]

> this could have been answered in your 1 post. Instead people must skirt around the subject offering their different solution instead of trying to teach someone.

Ya know, there's a theory about teaching a man to catch fish.... but sometimes it makes more sense to take a pre-caught fish.

Especially when he proposes two ships and eight nets to catch lunch.

owel told you what to do. Simple, works. Done.

> So i made this circuit in LTSpice. ... So whats the problem? Is it wrong?

Your first "threw together" plan shows both AC sources as a single transformer winding.

Your LT sim uses two separate (and not-CT) AC sources.

They are not even the same.

In your LT diagram (why do you draw 2*10000u, when SPICE has 20000u caps? I'll ignore the even-number caps), C1 C3 C5 C7 are in series. AND the C1-C3 junction is shorted to the C5 C7 junction. So most of the caps are redundant.

So is one of the bridges.

What do you WANT? +24V to power some antique preamp, and +48V phantom?

I really think that Phantom, being hung on the front of the chain, ought to be -completely- separate from Amplifier Power, usually stuffed into the last stage of the amp. I'm not the only one to think so.

Also that most home-brew (and many commercial) Phantom supplies are flawed.

And that jacking-up a few mA of 48V when you need 100 mA of 24V begs for two supplies.

But simplicity trumps all theory. This can work.

 

[3nity]

or use this:
http://fucanay.fischerworks.com/diy/Fetboy+24+48fromGreenPSU.gif

 

[imloggedin]

[quote author="PRR"]
Ya know, there's a theory about teaching a man to catch fish.... but sometimes it makes more sense to take a pre-caught fish.
Especially when he proposes two ships and eight nets to catch lunch.
[/quote]

But that doesnt teach him anything now does it? Im sure everyone on this forum learned everything by themselves.

But simplicity trumps all theory. This can work.

YAY! simplicity
Is it better to have a slightly higher voltage transformer and regulate it in case the input voltage on the transformer varies? Also, why is it better to have different value caps on each side?

 

[PRR]

> Will this power supply work?

The question is useless.

You have got better answers than it deserves. (Which is part of the problem.)

WORKS FOR WHAT ?????

Write your SPECIFICATION.

48V, 140 Amps (welder)
24V, 0.01 Amps (relay)
< $20
< 2 cubic inches
understandable by service personnel.

If you don't know, and say, what it must do, "will it work?" is not a valid question.


> why is it better to have different value caps on each side?

That was a stupid assumption on my part. Write the specs and then we can talk.

 

[imloggedin]

lol for a 3 channel (ya its odd number) fetboy preamp.

277.5ma-ish

 

[imloggedin]

[quote author="PRR"]> Will this power supply work?

The question is useless.
[/quote]

Not useless. You do not need to know the current requirements to tell me if the circuit i made will provide me the voltages i put forth (not under load) and wont blow up when i plug it in. The whole first page here is people wanting me to use their supplies instead of answering my question, to try and learn something.

And your the one thats even pissier than me. I just asked if my circuit would work. HAH

 

[imloggedin]

http://www.groupdiy.com/index.php?topic=2564 this guy didnt get flamed. he pretty much asked the same damn thing. he didnt give any current requirements, etc etc