highly stable AC->DC power supplies

Mar 27, 2026 Last reply: 3 months ago 5 Replies
C

One of the old simulator systems I maintain is a non-qualified sim that we got out of a junkyard and we put back together to use for procedural training and such like. So, for context, the general goal is to spend the least amount of money needed to keep it working as is.



I've been having some trouble with a few of the components lately, and after a bunch of troubleshooting, I believe the problem is that the 5V



60A and 12V 40A DC power supplies that feed them are not stable enough on the output. I.e., too much voltage variation under heavy load. The components in question are specified to only accept up to 100 mVp-p ripple, but I'm seeing up to 200 mVp-p variation on the 5V supply, and up to 400 mVp-p on the 12V supply.

The power supplies in place are some very cheap models obviously of Chinese extraction. And I think they are old as well, maybe around 20 years. So I'm wondering if I can fix my problem by purchasing new, higher quality power supplies. But after looking around on the Internet for a little while, I'm not sure what are the best brands, companies, or models to look toward. Any thoughts?


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J

We use a lot of MeanWell supplies in our products and they are very good. We use a 1KW 48V supply that costs about $170.

But you should get one and test it for ripple. You might add a filter.

Use remote sense.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

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T

Could it be as simple as replacig the bulk storage/smothing caps?

-especially if it's that old.

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E

Yeah that's what I thought. Old power equipment likely means old electrolytic capacitors which are drying up. A visual inspection might be revealing.

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L

I refurbished 'high quality' supplies used in flight simulators for NAVCAN in the 90's. The computer grade electrolytics used on the outputs of lower-voltage single-output units were invariably cooked.

As these used 2-stage filters, when the stressed section failed, the second stage masked the issue.

I think they were located on-site in a sealed wooden box, or something similar, with little air circulation.

RL

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S

What is the frequency of the ripple? It could be a seemingly unrelated input grounding problem corrupting the regulator reference portion of the supply. It will be better to repair or improve the performance of what you have, unless you have a lot of money to spend.

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