On Thu,6/1/2017 9:41 AM, Phil Kane wrote:
As Josh said earlier, be very concerned about the10 volt drop in the AC voltage measured at the load.
All great advice. Also, try to trace the wiring that feeds the outlet that the amp is plugged into. Possible causes of the high voltage drop are 1) conductors that are too small (AWG #14 is the smallest permitted for a 15A circuit, #12 for a 20A circuit); 2) bad splices; 3) miswiring of outlets or splices (reversals of hot and neutral, or hot and ground, or neutral and ground); 4) degraded outlets; 5) miswiring of the KPA500 power cable (like #3).
For a circuit carrying this much current from an electronic load, wiring should be a direct run of #12 (hot, neutral, and ground) from the power panel to the outlet. While #12 is not legally required for a 15A circuit, the larger conductors reduce IR drop.
AND -- load current to electronic loads is NOT a sine wave, but instead consists of pulses at positive and negative peaks of the waveform to recharge filter caps in the power supply. This causes IR drop to be greater than predicted by application of Ohm's Law to a sine wave. SO -- it's good engineering practice to oversize conductors on circuits for electronic loads. Two wire sizes is a good rule of thumb.
73, Jim K9YC ______________________________________________________________ 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
