[Power] Haiti power questions

[forster at ozonline.com.au]

> What did you use for your current measurement? Some sort of CT or a low 
> ohm resistor?

I used a commercial CT, a resistor is an option, it will also capture any DC components but you need to mess with line voltage. If you don't want to buy one they are easy to make
http://wiki.sugarlabs.org/go/Activities/TurtleArt/Using_Turtle_Art_Sensors#Measuring_AC_Amps

> 
> What frequencies are you expecting to see the most energy at?

I did a rough transcription of the waveform to Excel and did a fft on that, see http://wiki.laptop.org/go/Plug_packs#Harmonics
the most energy is at the fundamental, dropping off gradually so that at the 11th harmonic its half the current, maybe you need to square that to get energy?

Another question is which harmonic is killing the generators, comes down to lamination thickness, amortiser winding design etc.

> 
> What about at the lower power levels? Say like when the XO is just 
> sitting there idle on a full battery?  The current draw is much less but 
> the listed pf is much worse.
> 
Though not likely to be a problem. The power is low and the harmonics also low. I show two graphs at different charge levels. I am getting near my oscilloscope sensitivity.

Tony