[Elecraft] K3 - small power supply 110-240VAC

[Ron D'Eau Claire]

It's okay to apply a little reason when evaluating the specifications. That
25A rating is VERY conservative, as Elecraft spex always are IMX. 

I run my K3 from an Astron 20A with no problems at all. The 20A is rated at
20A Intermittent Commercial and Amateur Service (ICAS) and 16A continuous
commercial service (CCS). 

My K3 demands far less than 20A ICAS, even running 100 watts CW/SSB. Of
course, that's because both CW and SSB are very low duty cycle modes. The
peak current (just about 20 Amps worst case for my K3 looking into a low
SWR) only occurs at brief voice peaks or when the key is actually down in
CW. The average current is far below that, and far below the 16A CCS rating
of the Astron.

If I was going to run RTTY or FM at a full 100 watts, I'd be running the
power supply about 25% above its normal ratings only if I kept transmitting
for more than 5 minutes (ICAS assumes 5 minutes on and five minutes off).
Even if I wanted to run RTTY or FM constantly for an extended time, dialing
the K3 output power back 1 or 2 dB would put the load comfortably inside the
CCS rating of the power supply. 

Ron AC7AC

-----Original Message-----

>From the manual:  "Recommended supply: 13.8VDC @ 25A, continuous duty for
K3/100;