Interesting data, Charles. I assumed that running the KPA1500 (or KPA500) at lower power would keep the fan from running as much. I knew that efficiency changed with output power but I did not expect that it was this significant. If your data is correct there is 1000++ watts of heat to dissipate no matter what power level you use.
John KK9A From: charles k5ua Date: Fri Aug 17 01:17:49 EDT 2018 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 arch...@mail-archive.com
