There was a similar post about the KPA500 in the last year or so. Elecraft responded that the amp was designed for 500 Watts running less was less efficient and running amp at low power was doing it no favors.
With the KPA500, so many wanted 1500 W so now you have it, you want to run less? Sent from my iPhone ...nr4c. bill > On Aug 17, 2018, at 1:17 AM, char...@k5ua.com wrote: > > Thanks for the replies. > > Upon further testing, I have found that the efficiency of the KPA-1500 is > varies greatly with driving power. The following table illustrates the > relationships between exciter power, voltage, current, power-in(voltage x > amps), power-out, efficiency, and dissipated power. The following test was > made with the KPA-1500 into a dummy load and readings from the KPA-1500 > utility software. > > (Exciter)(Amps) (Voltage) (Power-In) (Power-Out) (Efficiency Pout/Pin) > (Dissipated Pwr) > 10w 29a 52.7v 1528w 375W 375/1528 = 24.5% 1205w > 15w 37a 52.7v 1950w 620w 620/1950 = 31.7% 1335w > 20w 43a 52.6v 2262w 861w 861/2262 = 38.0% 1413w > 25w 47a 52.6v 2472w 1060w 1060/2472 = 42.8% 1451w > 30w 51a 52.6v 2682w 1227w 1227/2682 = 45.7% 1420w > 35w 53a 52.5v 2782w 1380w 1380/2782 = 49.5% 1412w > 40w 55a 52.5v 2887w 1497w 1497/2887 = 51.9% 1382w > 45w 56a 52.5v 2940w 1600w 1600/2940 = 54.4% 1313w > 50w 57a 52.5v 2992w 1703w 1703/2992 = 56.9% 1315w > 53w 59a 52.5v 3097w 1825w 1825/3097 = 58.9% 1306w > > The remarkable thing is that DISSIPATED POWER appears to be relatively > constant from 375w output through 1825w output. This implies the KPA-1500 > will need to dissipate nearly the same amount of heat at low power output as > at high power output, if I am interpreting the data correctly. I would like > to know from Elecraft if this is normal behavior. > > Charles K5UA > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to n...@widomaker.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
