Electronics > Projects, Designs, and Technical Stuff
switching-PSUs: why can't you usually exceed the 50% of declared power?
tunk:
Here's a few others:
https://www.jonnyguru.com/blog/2012/12/03/death-of-a-gutless-wonder-iii-the-labors-of-hercules/
http://www.jonnyguru.com/blog/2013/03/11/death-of-a-gutless-wonder-iv-aces-low/
https://www.jonnyguru.com/blog/2014/05/12/death-of-a-gutless-wonder-v-uncool-to-the-max/
chriva:
Where did you load it and how?
If you don't have proper equipment to measure actual load, you can't really say "it blew at this and that wattage".
Just because a GPU states it'll only draw 150 Watts doesn't mean that is actual peak power. They can easily push almost twice that with a slight overclock.
Processors are pretty much as bad. Design power is far under their boost power draw
rsjsouza:
--- Quote from: 0db on May 23, 2020, 10:05:16 pm ---
--- Quote from: engrguy42 on May 23, 2020, 09:34:22 pm ---Where did you see this?
--- End quote ---
I bought a couple of AEROCOOL VX PLUS 550W just to make a few tests.
They litteraly exploded at 300Watt of load. And there was no PFC inside.
--- End quote ---
Others already mentioned what could be cheaper. Think about your own experience with the "explosion" and imagine the manufacturer used a cheaper 15A MOSFET trying to carry 25A or 30A on the 3.3 or 5V lines, or used a 30A MOSFET but reduced the size of the heatsink. Both scenarios are quite possible for a catastrophic scenario but rarely go alone: the use of lower quality PCBs with smaller current capacity, bad soldering job due to low salaries, use of components removed from other products, etc.
I have seen all these in a plethora of power supplies sold in the marketplace - the worst offenders were in the periphery markets such as Brasil and Argentina (the ones I know better), where the supplies were sold as "500W (300W real)"
0db:
--- Quote from: chriva on May 23, 2020, 10:14:38 pm ---Where did you load it and how?
--- End quote ---
I attached several bulbs in parallel to simulate the load. I started with a few bulbs to simulate 100Watt, then I added more bulbs to simulate 200Watt, 300Watt, and finally 500Watt. During the test I observed the ripple with an oscilloscope.
engrguy42:
Hold on here...some alarm bells are going off...
Some basic questions:
- Are these new or used units?
- What tests did you do?
The reason I ask is that decent ATX power supplies are required to provide some basic protection. They generally have supervisor circuits which monitor output current and voltage and shut down the switching MOSFETS quickly when out of range. They also have fuses. I've done a significant amount of testing on a decent ATX supply, and the supervisor circuit worked great. I overloaded it multiple times with a huge rheostat and it shut down instantly.
Now, I would be fairly certain that a Corsair unit would have these protections. So something seems fishy here. "The motherboard died??".
If you pay for used or extremely cheap power supplies you shouldn't be asking the question. You get what you pay for.
If you're paying for a decent, ATX power supply, I suggest you take a look at the protection circuits it's supposed to have (look at the ATX spec) and see what supervisor circuit is inside and what it's supposed to do.
I'm not saying nothing bad can ever happen, I'm saying a string of failures sounds more like user error (or cheap/used junk) than bad units.
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