PSU / Combine 12v and -12v rails for 24v?

  • Thread starter singlespeed
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In summary: AC adapter with a DC output, you could just use that to power the supplies, and then use an IEC cord to plug them into the wall.
  • #1
singlespeed
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I would like to increase my voltage on these PSU's to 24v. If I combine the -12v and +12v for 24v do I still get the high current of the 12v side?

+12v 70A

-12v .8A

24v... but what is the current potential?

610200994548PM_0003-vi.jpg
 
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  • #2
do I still get the high current of the 12v side?
No you don't.

You must still respect the -12V side's current rating which is typically only half an Amp or similar, so that will set your overall current rating for 24V operation. Note that you also require a floating (non ground referenced) load for it to work, this part is very important!
 
  • #3
uart said:
No you don't.

You must still respect the -12V side's current rating which is typically only half an Amp or similar, so that will set your overall current rating for 24V operation. Note that you also require a floating (non ground referenced) load for it to work, this part is very important!

Thanks for the reply, I figured it would inherit the lower amp side. Is there any way I can boost the current voltage to above 12? I'd like to see it slightly higher in the 14-16v range.
 
  • #4
ASSUMING the outputs are floating and completely independent, you may be able to put the power supplies in series (as you would with two 12V batteries). You should be able to use a mutlimeter (with the supplies turned on) to see what the voltage is between one supply's 12V supply, and the ground (or 12V output) of the other. If it's anything but open circuit, then a connection exists between the two of them.

Unfortunately, I suspect all of these will have the ground output tied to case and the ground prong on the plug, and hence be connected through the ground line, and you won't be able to do what I suggest above. A decent (current-limiting, short circuit protecting, etc.) adjustable two-channel power supply (up to 30V) will only run you around $150-$300 new, and possibly less somewhere like eBay. However, most of these will only supply 3 or 5A max, per channel (though you can connect them in series to get up to 60V, or put them in parallel to get 6 or 10A).

EDIT: Finished dangling thought
 

1. What is the purpose of combining 12v and -12v rails in a PSU for 24v?

The purpose of combining 12v and -12v rails in a PSU is to create a higher voltage output, specifically 24v. This is useful for powering devices that require a higher voltage input, such as motors or high-powered audio equipment.

2. How does combining 12v and -12v rails work in a PSU?

In a PSU, the 12v and -12v rails are connected in series, which means that the positive terminal of the 12v rail is connected to the negative terminal of the -12v rail. This results in a combined voltage of 24v when measured across the positive terminal of the 12v rail and the negative terminal of the -12v rail.

3. Can I combine any 12v and -12v rails in a PSU for 24v?

No, not all PSUs are designed to be able to combine 12v and -12v rails for 24v output. It is important to check the specifications of the PSU to ensure that it has this capability before attempting to do so.

4. Is there a limit to the amount of current that can be drawn from a combined 12v and -12v rail in a PSU?

Yes, there is typically a limit to the amount of current that can be drawn from a combined 12v and -12v rail in a PSU. This limit is usually specified in the PSU's specifications and should not be exceeded to avoid damaging the PSU or the connected devices.

5. Are there any safety precautions to consider when combining 12v and -12v rails in a PSU for 24v?

Yes, it is important to follow safety precautions when working with electricity. Make sure to disconnect the PSU from power before attempting to combine 12v and -12v rails. Also, ensure that all connections are secure and properly insulated to prevent any potential hazards.

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