Author Topic: 30A Adjustable Power Supply Suggestions  (Read 3006 times)

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Offline bostonmanTopic starter

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30A Adjustable Power Supply Suggestions
« on: June 04, 2023, 12:23:51 am »
I’m considering an adjustable power supply, maybe 30v and 20 or greater amps.

So far the ones I’ve found are expensive. Does anyone have any suggestions on an affordable one? I don’t really care about noise, and I already have power supplies, just need one with more current.
 

Offline donlisms

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Re: 30A Adjustable Power Supply Suggestions
« Reply #1 on: June 04, 2023, 12:42:08 am »
Let's see... power is volts * amps, so at 30 volts and 30 amps, that's 900 watts plus overhead...  Now the thought is... how much should we expect to pay for a moderately precise, reliable,  nicely designed device that operates at over a thousand watts?

I'm just suggesting that a place to start is to make sure your expectations are realistic. 
 

Offline bostonmanTopic starter

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Re: 30A Adjustable Power Supply Suggestions
« Reply #2 on: June 04, 2023, 12:47:04 am »
I didn’t use watts because it could imply low voltage and high current or vice versa. In any case, I agree with you, and it’s why I asked if anyone knows of somewhere that has decent prices.
 

Offline PCB.Wiz

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Re: 30A Adjustable Power Supply Suggestions
« Reply #3 on: June 04, 2023, 01:33:22 am »
You have not defined affordable, or if you need displays, but aliexpress often have the best prices.
https://www.aliexpress.com/item/1005005530478325.html
 

Offline mawyatt

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Re: 30A Adjustable Power Supply Suggestions
« Reply #4 on: June 04, 2023, 01:40:08 am »
The Korad KWR103 can do 30V and 30A, but limited to 300W total output power.

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Offline HalFoster

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Re: 30A Adjustable Power Supply Suggestions
« Reply #5 on: June 04, 2023, 09:23:07 am »
There are quite a few of the older power supplies from HP and others that would do - ePay has them fairly often.
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Offline barshatriplee

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Re: 30A Adjustable Power Supply Suggestions
« Reply #6 on: June 04, 2023, 10:21:26 am »
I'm afraid that it's not possible to find 30V,30A. However, Vantek DPS 3305P power supply is good.The maximum voltage is 32V, Maximum current is 5A.
 

Online coromonadalix

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Re: 30A Adjustable Power Supply Suggestions
« Reply #7 on: June 04, 2023, 11:31:23 am »
 

Offline Professzore

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Re: 30A Adjustable Power Supply Suggestions
« Reply #8 on: June 04, 2023, 12:10:22 pm »
Hi,

What do you exactly mean under "adjustable"? Variable voltage? If yes, what is the desired precision? Current limitation? If yes, what is the expected resolution?

30 V outpot at 20 Amps is way over the "safe" limit, you you may also consider using special connectors, and good cables.

Axiomet may offer something "less expensive", though, they'll be over 300 euros for sure. AX-3020L.
 

Online coromonadalix

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Re: 30A Adjustable Power Supply Suggestions
« Reply #9 on: June 04, 2023, 01:02:48 pm »
Safe limit of what ????   

The safe limit is the power outlet wattage, and or   yes  all the cables who goes to it, and from it

for sure at 800-900 watts  or more you get serious into power distribution

but i still dont see danger ???

had 120amps psu's  80 amps etc.   up to a 1kw,    the psu quality come first ...

buying cheap stuff trying to save money is a no nonsense if you want to play in theses wattages

Only once i had a chinesium brand in a smps psu   dual 30v 10 amps,  it did blow up after outputing 16 vdc at 2 amps for a long time,  trashed it,  and bought  serious brands
 

Online tautech

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Re: 30A Adjustable Power Supply Suggestions
« Reply #10 on: June 04, 2023, 01:29:00 pm »
Quite satisfied with my 40V SPS5042X and regularly push it to 25A though it's capable of 60A.
https://siglentna.com/power-supplies/sps5000x/
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Offline bostonmanTopic starter

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Re: 30A Adjustable Power Supply Suggestions
« Reply #11 on: June 04, 2023, 02:10:24 pm »
Quote
You have not defined affordable, or if you need displays, but aliexpress often have the best prices.
https://www.aliexpress.com/item/1005005530478325.html

You're correct, I should have specified a price range. I guess low hundreds would be good and this one seems like it's a great price (but haven't looked at the shipping yet because I can't get the site to display English).

Ideally 20A will suffice. I'm working on stuff at home for my job and it has a heater that draws about 15A cold. At work we have 20A and 30A BK supplies. Unfortunately I only have 10A supplies at home and thought this is a good opportunity to get a more powerful supply. As for precision and stability, I can measure (and adjust) the output voltage accordingly, and it just needs to be stable enough to a volt or so I guess.
 

Offline tooki

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Re: 30A Adjustable Power Supply Suggestions
« Reply #12 on: June 04, 2023, 04:15:02 pm »
I'm afraid that it's not possible to find 30V,30A. However, Vantek DPS 3305P power supply is good.The maximum voltage is 32V, Maximum current is 5A.
Why even respond with such drivel? Of course they’re available. Just because you don’t own one doesn’t mean they don’t exist!
 

Offline IanB

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Re: 30A Adjustable Power Supply Suggestions
« Reply #13 on: June 04, 2023, 04:24:02 pm »
but i still dont see danger ???

You have never created glowing hot metal from an accidental short? Never created smoke or fire? Never burned yourself by touching something hot?
 

Offline Professzore

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Re: 30A Adjustable Power Supply Suggestions
« Reply #14 on: June 04, 2023, 07:25:04 pm »
Hi,

Well. I'm a serious "safety first" guy. I've seen 20 V DC at (nearly) 20 A on short. It was not friendly at all. I've seen the result of an unwanted short and an arch at 300 V, around 1.5 A. Wasn't too nice either.

And these two are just a good example of about half what bostonman wants to handle (30 V, 30 A, technically 900 W). And there is no human involved in the above-mentioned incidents. What if some of this current flow through someone's body? At 30 V, it doesn't make any serious issues under normal circumstances, but it also depends on many factors. So, it's always better to be careful.

That's all. Everything else is a plain technical question.
 

Offline DavidKo

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Re: 30A Adjustable Power Supply Suggestions
« Reply #15 on: June 05, 2023, 06:47:11 am »
New or it can be used?

Old power supplies make sense for local pickup (linear with transformer - will be heavy and bulky).

New switching devices are quite compact. I have bought second hand Matsusada RK30-40 with 30V/40A for ~USD120 + shipping - 6kg, HxWxL 124x210x350mm.
 

Online edpalmer42

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Re: 30A Adjustable Power Supply Suggestions
« Reply #16 on: June 05, 2023, 07:14:42 am »
Xantrex and Sorensen make power supplies that can output that kind of power.  A few years ago I bought a dead Xantrex XKW 33-33 (33V, 33A).  I got lucky and was able to repair it.  There's a message thread about my adventures.  These supplies are always available on ebay.
 

Online coromonadalix

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Re: 30A Adjustable Power Supply Suggestions
« Reply #17 on: June 05, 2023, 10:28:31 am »
but i still dont see danger ???

You have never created glowing hot metal from an accidental short? Never created smoke or fire? Never burned yourself by touching something hot?


AND    seriously, you play with theses power you need good equipment and mostly watch what you are doing and dont leave nothing unattended

and for the pow / bang / smoke,   red wires / fused ones,  it mostly happens when you are not careful or do some abuses or do cheap setups trying to start things too fast or being to hasty

oh i'm not god  it happened once or twice ...  the chinesium cheap supply story  and  1kw server supply who did not get enough venting,  blowed itself up with only a car lightbulb 12vdc 5 amp

you play with theses powers  YOU HAVE THE RESPONSABILITY to do it correctly

I have Kikusui and Kepco psu's for now, i had  "KW"  output Lambda psu's,  had Xantrex  and Sorensen models in the past,  supplied tons of amps  for electroplating on a previous job


But all of this is derailing the OP thread

You need 900w of juice  anything is possible good or cheap  thats all
Do a good search, avoid crap, do your setup right ...
 

Online tautech

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Re: 30A Adjustable Power Supply Suggestions
« Reply #18 on: June 05, 2023, 08:40:18 pm »
Yet some years back when assessing a SMPS 30V 5A Asian PSU a Dr EE buddy recommended we test it with a 100A rated diode across its outputs < no smoke, current limiting and smart fan did its thing and only display drivers have been replaced in nearly 10 years of use.
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Offline rounin

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Re: 30A Adjustable Power Supply Suggestions
« Reply #19 on: June 06, 2023, 01:05:57 am »
Do you need 0V-30V, or is just adjusting a few volts around 20V-30V needed?

In a pinch I've used a lot of RSP series from meanwell for high-power, slightly adjustable PSUs. Eg RSP-1000-24 can adjust 20V-26.4V. Not a replacement for a bench PSU, but easily 1/10th the price of a proper TDK-Lambda or Sorensen.

No current limit. It will happily dump 40A into your DUT. But if its what you need its cheap. I've paralleled 4 of them to get 160A / 4kW into a DUT for < 1200$ for some one-off testing where I needed to test at 21V and 25V. (Running off a 3 phase 208V 30A panel, not at home.) (watch your breaker...)

Maybe just pair it with some fuse panel / breaker panel / test connector panel and just have it cut the load on fault instead of having a current limit. I did easily spend another 1k$ doing the fixturing for the test - don't cheap out on the wire, connectors, etc.
« Last Edit: June 06, 2023, 01:12:54 am by rounin »
 

Offline rounin

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Re: 30A Adjustable Power Supply Suggestions
« Reply #20 on: June 06, 2023, 01:06:58 am »
Also the HEP-1000 series is fanless, which is nice.
 

Offline TimNJ

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Re: 30A Adjustable Power Supply Suggestions
« Reply #21 on: June 06, 2023, 02:03:17 am »
I like Chroma’s 62006P. Quite configurable, big power envelope. You can find one used under $1000.
 

Offline bostonmanTopic starter

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Re: 30A Adjustable Power Supply Suggestions
« Reply #22 on: June 06, 2023, 03:09:34 am »
Quote
Do you need 0V-30V, or is just adjusting a few volts around 20V-30V needed?


I'm looking for one that does 0-30V. The one on Aliexpress for around $130 actually looks good (I could use the 30V, 20A  instead of the 30A).
 

Offline bostonmanTopic starter

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Re: 30A Adjustable Power Supply Suggestions
« Reply #23 on: July 10, 2023, 02:14:37 am »
I ended up purchasing a 30v (actually 31v), 20A power supply for somwwhere around $120.

To my surprise, it's very light. My 30v, 10A power supply is the weight of a concrete block. Looking more into this, I've learned that many power supplies are transformerless.

I'm curious and don't really understand. Have we reached a point where we've phased out transformers as a way to step down voltage?

After some reading, it looks like a capacitor is used to step down the voltage based on the reactance, but still, it's a bit confusing, and also seems like it's not a circuit that will last long.
 

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Re: 30A Adjustable Power Supply Suggestions
« Reply #24 on: July 10, 2023, 02:45:09 am »
I ended up purchasing a 30v (actually 31v), 20A power supply for somwwhere around $120.

To my surprise, it's very light. My 30v, 10A power supply is the weight of a concrete block. Looking more into this, I've learned that many power supplies are transformerless.

I'm curious and don't really understand. Have we reached a point where we've phased out transformers as a way to step down voltage?

After some reading, it looks like a capacitor is used to step down the voltage based on the reactance, but still, it's a bit confusing, and also seems like it's not a circuit that will last long.
Most compact PSU's are SMPS and do use a transformer albeit small and operating in the 10's of kHz. Even wallwart SMPS supplies use a tiny transformer.
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