Switch mode question

Is it permissable to run a couple of dc switch mode supplies in parallel to gain extra current capacity ? What are the potential problems Tnx

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Reply to
atec77
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Generally no, unless they were designed for it. But I figure you suspected that already.

Instability - two regulating "loops" fighting and one losing.

You *can* purchase units designed to operate as master/slave. If you don't already have some of those, it's crazy to go that route instead of just buying one that's man enough to do the whole job.

Reply to
who where

I suspected as much but finding one large enough is if possible very expensive , might have to reconsider making another linear

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Reply to
atec77

What Voltage current are you looking for?

Mik

Reply to
Mik DaDik

48Vdc 1500 watts
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Reply to
atec77

Meanwell SMPS ~$700 ea

RSP-1500-v, 1500W SMPS v = 5V, 12V, 15V, 24V, 27V, 48V...

70-110% V adj, alarm o/p, parallel up to 5400W, 12V aux.

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Reply to
Dennis

I have a large junk box , I have caps , sinks and transformer free , now those switches look like decent supplies but are way over my hobby budget , if I can source suitable pass transistors for a 48cdv rail building a regulator control board will be easy Thanks anyway , ebay offers 400 watts for under $100.00 delivered just nothing large enough atm out of China

Reply to
atec77

Yeah, I just checked the price out of interest.

25 yrs ago you might have picked up an old Telecom rectifier good for a few hundred amps.....
Reply to
Dennis

I have two of the old telstra transformers here from when I started with them about 30 + years ago and the tranny from a 150 amp dc tig , just sold my 3.5kw 48 vdc supply , I have a copy of switchmode power supplies spice and p so when time permits might build one There is a Honkers bloke who does 350 and 400 watt supplies very cheaply , perhaps one of the blade server 48Vdc remote supplies will show up at a fair price

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Reply to
atec77

You could link 4 ATX power supplies in series. You would have to open up 3 of them and cut the link between the negative terminal and earth. It will be safe if you hard wire all 4 outputs together in series in a way that they can not be disconnected. I think the only reason they earth the negative output is so that it doesn't float at a high voltage WRT mains. So if all your connections are good, the highest any output will float is 48V.

Modern ATX supplies typically have two 12V 20A rails. But many dont realise that they are not actually separate rails. The rails are separately filtered with caps, but come from a single SM transformer. (typically)

So each ATX supplies 12V at 40A. Cost is about $40 each from ebay, so $160 is your total.

Reply to
Mr Mac

I thought about it but I need 48vdc @1500 watts , atx wont cut it but I can get cheap Asian industrial supplies @450watt each , will have to check the schematic to see if it might work Ta

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Reply to
atec77

48V x 40A = 1920W
Reply to
Mr Mac

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