Author Topic: Safe to test stability of power supply board by shorting output?  (Read 1246 times)

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Offline skillz21Topic starter

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Safe to test stability of power supply board by shorting output?
« on: November 05, 2018, 08:30:41 am »
I have this: https://ebay.us/7Wb9oM
I want to test the stability of this power supply. Since it has built-in current limiting, is it fine for me to simply set a voltage, say 5v, set a current limit of 5 amps, and just short the output and leave it? The website says not to short the output for very long, but since it has current limiting, is it safe? Or will i end up burning the board?
 

Offline Rerouter

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Re: Safe to test stability of power supply board by shorting output?
« Reply #1 on: November 05, 2018, 09:20:26 am »
My eye is caught by the "0.8V" minimum on the output, It may not like a hard short.

Equally full open to a sudden short will be the hardest test you can do on a PSU, until the control loop responds it can have far far more than your 5A set point, this can pop transistors if its not well built

The fact it says not to short the output for long would back up that 0.8V minimum, it may be that with a hard short it cannot regulate it.
 

Offline skillz21Topic starter

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Re: Safe to test stability of power supply board by shorting output?
« Reply #2 on: November 05, 2018, 09:38:04 am »
My eye is caught by the "0.8V" minimum on the output, It may not like a hard short.

Equally full open to a sudden short will be the hardest test you can do on a PSU, until the control loop responds it can have far far more than your 5A set point, this can pop transistors if its not well built

The fact it says not to short the output for long would back up that 0.8V minimum, it may be that with a hard short it cannot regulate it.
The one that I bought wasn't that exact web page, it is just the same type. Well, maybe I should have asked first... I did actually try shorting, but at a very low voltage (3v). I took it up to about 3A before I disconnected and decided to ask on here. So I'm guessing you guys recommend I don't do this again? (PSU board it still working properly BTW)
Thanks for the help.
 

Offline pelule

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Re: Safe to test stability of power supply board by shorting output?
« Reply #3 on: November 05, 2018, 12:14:12 pm »
Quote
Output voltage: 0.8-28V (continuously adjustable).
IMHO this is the lowest adjustable stable output voltage, not related to a short (0V).
A short creates at the given current limit conditon the maximum power dissipation for the supply.
Thus surviving depent on the thermal design mainly.
If you like to test the performance on the safe side - short only a short time (pulse generator, ~100ms) and in addition observe the temperature of the gear.
/PeLuLe
You will learn something new every single day
 

Offline David Hess

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Re: Safe to test stability of power supply board by shorting output?
« Reply #4 on: November 06, 2018, 03:50:45 am »
Just because it has current limiting does not mean it has sufficient thermal protection to drive a continuous short.
 


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