Swiching Power Supply question

Jul 27, 2016 14 Replies

Just recieved a Mean Well quad output power supply. After powering it up and testing output I get drastic flucuations on all outputs, a ticking sound and the green indicator light flashing. I have input power properly set to 120V. Does this need to be tested under load? Or is the thing possibly defective?


Try loading each output with about 5-10% of their rated current and see what happens. Report back.

Try to figure out which supply is used for the feedback and load it up a bit. These supplies do need a minimum load to be stable.

I'll have to dig deep in my supplies to find power resisters. Haven't had much use for them recently I'll let you all know.

You should NOT have to load a properly designed test bench power supply these days for it to give you a stable output.

I have seen a bunch of garbage bench supplies these days. Poorly short circuit protected, etc. Oh they're cheap but need to spend a bit more for a decent one I guess.

Time for someone to start a new power supply company maybe.

What decent supplies are others using ? Chinese made or otherwise.

boB K7IQ

This is not a test bench power supply. Iit is an enclosed switching supply meant to be mounted in a case with the device it is powering. BTW I just tested it with the +12V under a load with a power resister and all outputs worked (though not withini very acceptable tolerances.

+24 was closer to 26 though I think with that under load it should work fine)

Found an old 120 ohm power resistor and put it on the +12V output. All outputs seem to now function, though not in acceptable tolerance. Under load they should be OK. BTW This is for a Eurorack Modular Synthesizer I am home building. Fingers crossed I don't blow anything up. (Though the sound might be worth recording) Thanks for the suggestion John S.

-Slackmeister

We have used zillions of MeanWell open-frame supplies, and they have been great.

Most multi-output switchers close their feedback loop on one output, so the others have mediocre regulation. At light loads, the outputs can go way up.

John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com

You could add a linear regulator to the outputs that go too high if the current isn't too high.

I just had to add zeners across my un-regulated outputs of a flyback with multiple outputs which works fine. Luckily those outputs don't source a lot of current during times of high input voltage and wide PWM.

boB

"caps"? Capacitors? Add to Input? Output? Value(s)?

Or do you mean to wear an aluminum foil cap? Top cap? Derby? Straw cap?

Or is he pointing out my misuse of capital letters?

Well, Meanwell supplies **are** being counterfeited.

If you bought it from the good folks on fleabay or Ali I would bet money on that being the case.

Contact Meanwell with the serial number and ask them if it's one of theirs.

--sp

Best regards, Spehro Pefhany Amazon link for AoE 3rd Edition: http://tinyurl.com/ntrpwu8

In this case it was my flyback supply with not the best cross regulation. Yet. (I hope)

boB

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