Parallel Power Supplies - Will it Work?

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Philadelphia Frank

Can you use two power supplies for one PC?

I was given a really nice server case yesterday. I have quite a few
IDE harddrives and CDROMs as well as two ATA 133 cards. So I'm
thinking about using this server case, along with a bunch of drives,
as my regular PC.

I have a PC Power and Cooling brand 450W PS already. I also have a few
pretty decent AT and ATX power supplies. Can I use one of the other
power supplies to power some of the hard drives or CDROMs?

Does the 5 and 12 volt feeds to the drives have any connection to the
data transfer. Do they need a "common" or are they simply power (like
I'm hoping). Will the mainboard care that the drives are not being fed
with the same source as the board?

The AT power suppy will power up as soon as I put 110V to it so I
don't need that "power up" signal from the mainboard.

Thank you for your time and help;
Frank
 
Yes you can if you make sure the commons and case grounds
are tied together.
From what you've said though I don't think you'll
need more than the PC Power and Cooling supply
though.
 
Philadelphia said:
Can you use two power supplies for one PC?
Yes.

I was given a really nice server case yesterday. I have quite a few
IDE harddrives and CDROMs as well as two ATA 133 cards. So I'm
thinking about using this server case, along with a bunch of drives,
as my regular PC.

I have a PC Power and Cooling brand 450W PS already. I also have a few
pretty decent AT and ATX power supplies. Can I use one of the other
power supplies to power some of the hard drives or CDROMs?

Does the 5 and 12 volt feeds to the drives have any connection to the
data transfer. Do they need a "common" or are they simply power (like
I'm hoping). Will the mainboard care that the drives are not being fed
with the same source as the board?

The AT power suppy will power up as soon as I put 110V to it so I
don't need that "power up" signal from the mainboard.
Click to expand...

Chances are that the "commons" of both PSUs are internally tied to
their PSU's chassis, so if both PSUs are screwed to the same metal
case, they will have common returns.
 
Can you use two power supplies for one PC?
Yes


I was given a really nice server case yesterday. I have quite a few
IDE harddrives and CDROMs as well as two ATA 133 cards. So I'm
thinking about using this server case, along with a bunch of drives,
as my regular PC.
Click to expand...

Sounds good
I have a PC Power and Cooling brand 450W PS already. I also have a few
pretty decent AT and ATX power supplies. Can I use one of the other
power supplies to power some of the hard drives or CDROMs?
Click to expand...

Yes, since you're wanting to use two (independant) power supplies instead
of a redundant PSU "system", powering the hard drives (and whatever else
the 2nd PSU has ample power to spare) is the best divsion of power without
having to cut and solder the ATX motherboard connector.

However, I'm going to assume that at least the AT power supplies, while
they might be "pretty decent", they're also likely to be fairly old at
this point. It might be best to use a newer power supply rather than one
past half of it's expected lifespan.

Does the 5 and 12 volt feeds to the drives have any connection to the
data transfer. Do they need a "common" or are they simply power (like
I'm hoping). Will the mainboard care that the drives are not being fed
with the same source as the board?
Click to expand...

No, the motherboard and drives don't "care".
The two power supplies should have a common ground. Their metal casings
are grounded, so if you screw them into a metal system case (the usual way
of mounting a power supply!) , they're making good contact with the system
case and that is the common ground.

The AT power suppy will power up as soon as I put 110V to it so I
don't need that "power up" signal from the mainboard.
Click to expand...

That's a negative thing though, it means you'll have to either ALWAYS have
it running, manually turn it on and off every time, or use a relay... far
easier to just make the second power supply an ATX too, then take a tap
splice to connect the two unit's PS_On wires together. That means the
motherboard will be 'sinking the current from both units PS_On lines, but
that doesn't seem to be a problem, I've done it before and even have a
syste sitting in front of me that's running fine set up this way.
 
Thank you for answering my questions. I never considered the age and
life span issues. When I posted my question, I did not understand how
the motherboard turned on the power supply, I did not know about the
PS_On wires going to common.

Using the ATX power supplies is definitely the better idea.

Thank you again for all the help;

Frank
 
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