On Sun,3/22/2015 1:20 PM, Jack Brindle wrote:
The two sentences are not in conflict. You should expect a major drop in HV on key-down due to losses in the power supply. This includes the components in the KPA500 (transformer, etc), the power cord, plug, wall outlet and wiring all the way to the main pole transformer. You can’t do much about most of this, but making sure the power cord can handle the current without overheating is a great idea. Of course this problem is worse with a 120V supply than 240V since the current is proportionately higher.
IF the wiring between the breaker panel and the outlet is under your control, it is a very good move to use bigger copper for that run. #14 is minimum for a 15A circuit, #12 for a 20A circuit, but going up to #`10 will reduce the IR drop under load. When doing the calcs, remember that the line current is NOT a sine wave, but rather pulses centered around the peaks of the waveform to recharge the input filter caps. That means that the voltage drop will be greater than if it were a sine wave.
I have 240VAC in the shack to run my big tube amps, so I also run my KPA500 from 240V.
73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
