[chbot] Scrounging for big switch mode PSUs - clarifications

[Mark Atherton]

Wonder what the lowest cost new SMPSU you can buy that has a credible 
specified MTBF ?

Also, ask Alan at Echotech, he hoards such things, although 48V really 
is heading towards a telco product.

I think you can go down to 100V, so how about 2 x 48V, 30A units goosed 
up to 56V in series, just less stuff to wire up.

Recommend you clean out any used units with compressed air and replace 
the fans - a cool PSU is a happy PSU.

Electro's also don't like the heat, so maybe budget for replacing them (?)

You know what you are doing Mr. Power !

-Mark


On 8/03/2019 3:40 PM, Peter Harris wrote:
> To clarify
> I am looking for mains powered DC supplies. The outputs must be 
> floating to allow series connection.
>
> Re series connection and power.
> P = V x I so power rises in proportion to V
> A single supply delivering 20A at 50V yields 1000W
> 2 of these in series will deliver 20A at 100V or 2000W
> The 3 x 1000W 48V supplies in series will deliver 20.83A at 144V == 3kW
>
> Series connection of PSUs is fine provided their output isolation is 
> sufficient to withstand the combined series voltage. Parallel 
> connection is much more difficult but is not required here.
>
> "Caged" refers to the metalwork enclosing the electronics. Here are 
> the unit's I'm considering
> https://www.aliexpress.com/item/Transformer-Switch-Mode-Power-Supply-DC-48V-3A-5A-7-5A-10A-15A-20A-150W-240W/32908080499.html?spm=a2g0s.13010208.99999999.265.1e3f3c002rOuom
>
> Thanks to all who have responded so far.
> I have been to Molten Media unfortunately they had nothing suitable.
> I had not considered a welder, I will do some research.
>
> I feel a talk at the next meeting coming on :)
>   P
>
>
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