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Electrolytic capacitor in ACDC power module is not specified?

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Internal operating frequency is quoted at 100KHz so it probably uses ceramic capacitors on the output side. Quite possibly with such low input currents it uses them on the input side as well.

Brian.
 
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Thanks, but at 20W, and down to 85VAC input, and at that small size, (and small price) then i am sure you would agree that it must contain an input electrolytic capacitor? (rated 450V).
Also, looking at the inrush current, of up to 40A....there must be a wet electro in the input there for that...
Also, power factor is 0.5...all point to an internal input wet electro.

The big question is........what is its hour and temperature rating of the input wet electro cap?.....why do they think they can sell this module without even stating this important detail?

...Output , i conceed , is up for grabs, and most likely to be sold poly on the output....at least up to the 24V output.
--- Updated ---

The RAC20-K datasheet says the module is rated 16000 hrs at 55degc...that woudl mean its input electro cap being rated 512000 hrs at 105degc...surely this is way off?

Do you agree the RAC20-K datasheet temperature/hours rating doesnt make sense?
--- Updated ---

....wooooops....i meant 500 hours at 105degC......
that would imply 500 hrs at 105degc for its input electro capacitor......thats very poor....but why dont they just give the electro cap part number...and give assurance that they wont use a worse one in future?
 
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It needs a 68uF / 450VDC electro cap to run at 85Vac at full power - given it is 1" x 2" footprint and not that tall - there is little room for a high quality electro

thus it is another type of cap - likely solid AL.
 
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have a look how large a 68uF 450vdc cap is compared to the size of that converter, also just because you can't find something on the net ....
 
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have a look how large a 68uF 450vdc cap is compared to the size of that converter, also just because you can't find something on the net ....
Click to expand...
...I see your point, thing is, the lifetime at 500 hours at 85degC sounds like an wet electrolytic cap lifetime.
As such, with the small size....that seems to point to wet electrolytic if anything as they give the most capacitance per unit volume.....so yes, i see your point, though are we looking at some kind of special wet electrolytic?
The module is around £8, so it suggests something fairly cheap.

I suppose i am going to have to buy one and bust it apart.......though with a quoted lifetime of 500hrs at 85degc, may be a good idea to just look for a module with a better lifetime....unfortunately the type of modules where you put in your own electro cap dont exist above 15W.
 

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Notice that Recom open frame AC/DC module RACM60-K has similar lifetime estimations. They are specifying for 40°C instead of 25 and 55 °C with RAC20-K, the points are on a line in the semi-logarithmic curve. RACM60 is obviously using standard electrolytic capacitors at in- and output, thus I'd assume the same for the small module.

1628601962457.png
 
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