[Elecraft] 48 volt PS

[Dave B]

Ted.

Best to box the PSU and silence the fan with sound deadening material
without affecting airflow.  In effect, creating a "silencer" for the air
inlet, and maybe outlet.

For that sort of power level 500W and above, and the small size of those
PSU's, the cooling is critical for a long life.  So, the gutsy but noisy
fan is there for a reason.   Replace it with a quieter one if you must,
but don't compromise the airflow.

As to RFI.  All SMPS's create it, some more than others, by design.  It
can be filtered of course, but to do that properly will also cost a fair
bit.

Voltage divider?  Just use a dedicated 12 (13.8V) PSU for the K3.  You
then have redundancy for when the 48V supply quits at some point.   If
you must, one of the common "Telecom" DC/DC converters, (48 to 15V, and
a linear post reg) to get your K3 supply.

But, make sure you know which side of any such DC/DC converter is
common, if not isolated.  You may be (unpleasantly) surprised!

Remember the KISS principle.

73  Dave G0WBX.


On 09/12/17 19:47, elecraft-request at mailman.qth.net wrote:
> I need to buy a 48 VDC power supply for a project that requires that voltage ? and possibly along with a voltage divider to power the K3.  One suggestion I?ve received is the MeanWell SE 600-48.  The online reviews are good, noting only high fan noise, which can be fixed by replacing the fan with a Vantac Stealth.  But I haven?t seen anything about RFI.
>
> Anyone know this PS who could say something about the RFI question?  Anyone have other suggestions for 48 VDC and at least 12 amps?
>
> Thanks, as always,
>
> Ted, KN1CBR