Robert Bruninga wrote: > Yes, as far as VOLTS and as AMPS as averages are concerned. Such as > average power. A 1500W resistor will be 1500W whether on DC or RMS AC. > > But the power loss in wires feeding that resistor will have greater loss > on AC because of two factors important in distribution systems: > > 1) SKIN EFFECT where the AC current is pushed to the outside of the wire > so that not all the wire is carrying the same current. Thus the wire is > not as effective since not all of its copper is being used in an AC system

The skin depth in copper at 60Hz is 8.47mm; this means that until you are using a conductor with a diameter greater than 2 x 8.47mm = 16.94mm (about 0.67"), the AC resistance is the same as the DC resistance. <https://en.wikipedia.org/wiki/Skin_effect> > 2) Peak power losses. As you note, the RMS current is the same, but the > PEAK current is 1.4 times higher during the peak of the waveform and since > that is where the most power is delivered that is also where the most loss > occurs in the wire. So the average power lost in the wire for AC is > almost twice (1.4 squared) the loss in the same wire at DC. > > Google it... "For a cyclically alternating electric current, RMS is equal to the value of the direct current that would produce the same power dissipation in a resistive load." - <https://en.wikipedia.org/wiki/Root_mean_square> Cheers, Roger. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)