Hi gang,
I was wondering if you could help me with figuring out if my power supply is dual rail as it's meant to be because I've done two tests which both suggest to me that it's actually single rail.
The power supply I've got is a Cooler Power GX700 from ebay, there are loads of them for sale on there. The sticker on the unit says that it has dual 12v rails with 24A each rail.
I'm planning on using the unit as a power supply for my battery charger (for my remote control planes). I already converted one power supply over in the usual manner described in numerous threads on the subject, but the unit didn't have the overload protection it was supposed to and it died when I drew too much current from it. This unit (the GX700) is a replacement which is supposed to have plenty of power for my needs and proper over current protection.
Anyway, I went to test the PSU to see if if actually does have the dual 12v rails, as I have the suspicion that this ebay seller may be selling power supplies that don't meet their own advertised specifications. My understanding is that with a dual rail power supply, each rail has it's voltage regulated separately. This means that one rail can be placed under load, causing its voltage to drop a bit, while the other rail will remain unaffected and still put out it's full voltage.
To test if this was the case, I cut one of the yellow and one of the black wires, and connected both to a 55w headlight bulb in order to place one of the rails under load. This caused the voltage on that line to drop from 11.95 volts to 11.25 volts (I didn't have the 5v under load which I expect caused the voltage to drop under load more than it normally would have).
I then went to test the voltage of all the different yellow wires, expecting some to be at 11.25volts (due to being on the same rail as the light bulb) and others to still be at 11.95volts (as they would be on a separate rail which was not under load so should still read the full 11.95). What I found was that every single yellow wire read 11.25 volts. This strongly suggests to me that the unit is a single rail power supply, not a dual rail.
I then did some reading online, and found this article: http://www.techpowerup.com/forums/archive/index.php/t-147571.html which says that you can test if the PSU has multiple rails with a multimeter by testing the connectivity between all the yellow wires. If all the yellow wires are electrically connected to each other, then this apparently suggests that they are all sharing the one rail. If it is a dual rail power supply, then apparently one set of yellow wires should be connected and a second set should also be connected, with no connection between the two sets. I did the test with my multimeter as described, and found that all the yellow wires were in fact electrically connected to one another.
So, I've found that when one 12v wire is put under load the voltage on all the yellow wires drops, and I've found that all the yellow wires share a common connection. Does this suggest that my PSU is actually single rail and not dual rail, or is there another explanation for my observations?
If this is the case, do you think it would be a single rail of 24A or a single rail of 48A? If the latter, I think this would pose a serious safety hazard as it would allow a single wire to carry 48A which is probably enough to cause it to catch fire.
Thanks for your help!
I was wondering if you could help me with figuring out if my power supply is dual rail as it's meant to be because I've done two tests which both suggest to me that it's actually single rail.
The power supply I've got is a Cooler Power GX700 from ebay, there are loads of them for sale on there. The sticker on the unit says that it has dual 12v rails with 24A each rail.
I'm planning on using the unit as a power supply for my battery charger (for my remote control planes). I already converted one power supply over in the usual manner described in numerous threads on the subject, but the unit didn't have the overload protection it was supposed to and it died when I drew too much current from it. This unit (the GX700) is a replacement which is supposed to have plenty of power for my needs and proper over current protection.
Anyway, I went to test the PSU to see if if actually does have the dual 12v rails, as I have the suspicion that this ebay seller may be selling power supplies that don't meet their own advertised specifications. My understanding is that with a dual rail power supply, each rail has it's voltage regulated separately. This means that one rail can be placed under load, causing its voltage to drop a bit, while the other rail will remain unaffected and still put out it's full voltage.
To test if this was the case, I cut one of the yellow and one of the black wires, and connected both to a 55w headlight bulb in order to place one of the rails under load. This caused the voltage on that line to drop from 11.95 volts to 11.25 volts (I didn't have the 5v under load which I expect caused the voltage to drop under load more than it normally would have).
I then went to test the voltage of all the different yellow wires, expecting some to be at 11.25volts (due to being on the same rail as the light bulb) and others to still be at 11.95volts (as they would be on a separate rail which was not under load so should still read the full 11.95). What I found was that every single yellow wire read 11.25 volts. This strongly suggests to me that the unit is a single rail power supply, not a dual rail.
I then did some reading online, and found this article: http://www.techpowerup.com/forums/archive/index.php/t-147571.html which says that you can test if the PSU has multiple rails with a multimeter by testing the connectivity between all the yellow wires. If all the yellow wires are electrically connected to each other, then this apparently suggests that they are all sharing the one rail. If it is a dual rail power supply, then apparently one set of yellow wires should be connected and a second set should also be connected, with no connection between the two sets. I did the test with my multimeter as described, and found that all the yellow wires were in fact electrically connected to one another.
So, I've found that when one 12v wire is put under load the voltage on all the yellow wires drops, and I've found that all the yellow wires share a common connection. Does this suggest that my PSU is actually single rail and not dual rail, or is there another explanation for my observations?
If this is the case, do you think it would be a single rail of 24A or a single rail of 48A? If the latter, I think this would pose a serious safety hazard as it would allow a single wire to carry 48A which is probably enough to cause it to catch fire.
Thanks for your help!