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<div class="moz-cite-prefix">Wonder what the lowest cost new SMPSU
you can buy that has a credible specified MTBF ?</div>
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<div class="moz-cite-prefix">Also, ask Alan at Echotech, he hoards
such things, although 48V really is heading towards a telco
product.</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">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.</div>
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<div class="moz-cite-prefix">Recommend you clean out any used units
with compressed air and replace the fans - a cool PSU is a happy
PSU.</div>
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<div class="moz-cite-prefix">Electro's also don't like the heat, so
maybe budget for replacing them (?)</div>
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<div class="moz-cite-prefix">You know what you are doing Mr. Power !</div>
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<div class="moz-cite-prefix">-Mark</div>
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<div class="moz-cite-prefix">On 8/03/2019 3:40 PM, Peter Harris
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CANYo+TubGtAT68z8NNgaNHKj+MOn4m0+jmgxX++PmHzxsezpnA@mail.gmail.com">
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<div>To clarify<br>
</div>
<div>I am looking for mains powered DC supplies. The outputs
must be floating to allow series connection.</div>
<div><br>
</div>
<div>Re series connection and power. <br>
</div>
<div>P = V x I so power rises in proportion to V<br>
</div>
<div>A single supply delivering 20A at 50V yields 1000W</div>
<div>2 of these in series will deliver 20A at 100V or 2000W<br>
</div>
<div> </div>
<div>The 3 x 1000W 48V supplies in series will deliver
20.83A at 144V == 3kW<br>
</div>
<div><br>
</div>
<div>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.<br>
</div>
<div><br>
</div>
<div>"Caged" refers to the metalwork enclosing the
electronics. Here are the unit's I'm considering<br>
</div>
<div><a
href="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"
moz-do-not-send="true">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</a><br>
</div>
<div><br>
</div>
<div>Thanks to all who have responded so far.<br>
</div>
<div>I have been to Molten Media unfortunately they had
nothing suitable.</div>
<div>I had not considered a welder, I will do some research.</div>
<div><br>
</div>
<div>I feel a talk at the next meeting coming on :)<br>
</div>
<div> P<br>
</div>
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