I have come across two identical Samsung PSCF401601A(C) SMPS units. They are the power supplies from Power Mac G4 with the Mirrored Disc Drives (google Power Mac MDD power supply for results)
The interesting thing about them is that they have +25V rails in addition to the standard +/- 12, 5, and 3.3. I am currently trying to build a power supply for an audio power amp and 25V is a very workable voltage for audio power amps.
However I would need +25V and -25V rails, and these units only have +25V. So the basic electronically-oriented person would say to run them in series with the center point your ground reference.
But, this is mains-connected stuff, so it's no light task to go around wiring up things that are ground to things that are hot, as earth is... earth. And it will short together and most likely explode.
My inspiration for the project is **broken link removed** ... however he made some modifications to his SMPS to create a +/- supply. (the reason I do not use the -12 rail is that it does not have enough current rated.)
I do not posess the SMPS that was used on that website; if I did I could follow his isolation instructions and determine exactly what they did. However the datasheet/website are at these locations:
American Skynet Electronics
**broken link removed**
From reading it looks like he was just extremely careful to make sure that no part of the output was in any way connected to chassis ground. I believe I am capable of properly performing a similar isolation on another SMPS.
Assuming no part of a standard ATX power supply's output ground is connected to earth ground, then it should be "safe" to connect two of them in series, correct? I just want to confirm that connecting two switched-mode power supplies in series works the same as other power supplies such as batteries (which it should, in theory)
I put safe in quotes because I'm pretty sure disconnecting from earth ground makes it a fairly unsafe circuit that does not meet any safety standards.
This is the type of thing I will have on a breaker-ed circuit which I turn on from several feet away after clearing flammable objects from the vicinity
I want to confirm my theory is correct before I try it as these power supplies can be sold on ebay for about $80 each if I end up unable to use them. (they came from macs, thats why)
I will most likely try the isolation on a cheaper ATX or AT power supply (which I get for $0-$5 most places) to check the theory and practice the proper isolation techniques before I hook up my babies.
If all goes well I will post pictures and document the whole process so other people can get themselves killed.
The interesting thing about them is that they have +25V rails in addition to the standard +/- 12, 5, and 3.3. I am currently trying to build a power supply for an audio power amp and 25V is a very workable voltage for audio power amps.
However I would need +25V and -25V rails, and these units only have +25V. So the basic electronically-oriented person would say to run them in series with the center point your ground reference.
But, this is mains-connected stuff, so it's no light task to go around wiring up things that are ground to things that are hot, as earth is... earth. And it will short together and most likely explode.
My inspiration for the project is **broken link removed** ... however he made some modifications to his SMPS to create a +/- supply. (the reason I do not use the -12 rail is that it does not have enough current rated.)
I do not posess the SMPS that was used on that website; if I did I could follow his isolation instructions and determine exactly what they did. However the datasheet/website are at these locations:
American Skynet Electronics
**broken link removed**
From reading it looks like he was just extremely careful to make sure that no part of the output was in any way connected to chassis ground. I believe I am capable of properly performing a similar isolation on another SMPS.
Assuming no part of a standard ATX power supply's output ground is connected to earth ground, then it should be "safe" to connect two of them in series, correct? I just want to confirm that connecting two switched-mode power supplies in series works the same as other power supplies such as batteries (which it should, in theory)
I put safe in quotes because I'm pretty sure disconnecting from earth ground makes it a fairly unsafe circuit that does not meet any safety standards.
This is the type of thing I will have on a breaker-ed circuit which I turn on from several feet away after clearing flammable objects from the vicinity
I want to confirm my theory is correct before I try it as these power supplies can be sold on ebay for about $80 each if I end up unable to use them. (they came from macs, thats why)
I will most likely try the isolation on a cheaper ATX or AT power supply (which I get for $0-$5 most places) to check the theory and practice the proper isolation techniques before I hook up my babies.
If all goes well I will post pictures and document the whole process so other people can get themselves killed.