Dual PSU

  • Thread starter Thread starter Remo
  • Start date Start date
R

Remo

Hi all,

I wonder if there is any possibility of connecting two ATX PSUs
together in a simple way without any electronic circuits.

Thanks..
 
The short answer is NO. The longer one is, it is possible to back up
one with a second relatively easily, but not to share the load. There
will be some losses however in so doing, which would probably throw
the
voltages out of spec.
 
Hi all,

I wonder if there is any possibility of connecting two ATX PSUs
together in a simple way without any electronic circuits.

Thanks..
Click to expand...

Well, where exactly do you draw the line, calling something an electronic
circuit instead of an electrical circuit? Any halfway decent engineer
will find a way to do it using the most parts, the highest complexity
possible, but we'd need to know exactly what your specific needs are to
advise of the best alternative.

The easiest, generic answer would be:

By using a clip-on splice connector, connect both supply's PS_ON (green
wire, pin 14) together.
http://69.36.189.159/usr_1034/atx_on.gif

That's all you need to get the 2nd power supply to turn on when you power
on the system, but each supply still acts independantly, no current
sharing, and depending on the particular supplies you may need a load on
the 5V rail of the supply not connected to the motherboard... just about
anything will do, a 10 Ohm 5W power resistor, a hard or optical drive,
etc.

Many people asking about use of a 2nd power supply are starting out with
one of insufficient capacity... might be just as well to buy a higher
wattage power supply.
 
Remo said:
Hi all,

I wonder if there is any possibility of connecting two ATX PSUs
together in a simple way without any electronic circuits.

Thanks..
Click to expand...

Although you cannot "parallel" the outputs ...I certainly have heard of
pople
using a 2nd supply to run the harddrive (for example)

the supply running the drives can be turned on first
 
I wonder if there is any possibility of connecting two ATX PSUs
together in a simple way without any electronic circuits.
Click to expand...

Only if they power different devices, such as by having one power
supply run everything on the motherboard and the other supply run all
the disk drives.
Be sure to connect the grounds of both power supplies together, either
by bolting them to the same metal chassis or by running 2 fairly heavy
(#18 or thicker) separate ground wires between their cases.

You never want 2 voltage outputs to be connected together, even if
they're supposed to be at the same voltage because in reality they'll
be slightly different and cause the voltage regulator of each supply
to become confused when it tries to adjust the voltage but the output
doesn't react as expected because the other supply is trying to
control the voltage line separately.
 
Thank you, I did it :)
I removed all non-motherboard power connectors and connected them to
the second PSU. The second PSU handles optical drives, harddrives and
all case fans; the main PSU runs the ATX power.
Firstly I turn on the second PSU and then the motherboard switch, no
problem for now, it works...
 
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