Sorry for not being clear.
1. By "show only the traces with the scope functioning fine",
I mean remove all cases where as you said in post # 27:
"the PROGRAM is GOING CRAZY",
you basically did that already.
2. Not clear why you can't get a single scope channel working and the other off,but lets leave that for know.
3.The software show the 'spectral content' of the signal in the frequency window-The same one were it also shows the THD %.
i.e The "Frequency" window.
That is the "Fourier Transform" / "Fourier series" of the Signal.
4."the generator in Idle" at post #28 looks very different than those at post # 30.
Both the scope signal in time and it's "frequency spectral content" are very different.
One has harmonics of 60Hz at 120,180 etc.
The other has a "disturbance" at just under 2000Hz ,4000Hz ,6000Hz etc
This "generator in idle" is a bit of a puzzle when compared with the heater load cases.
That high frequency content(2000Hz and above) can be cleaned-up relatively easily ,if it originates from the generator itself.
The measurements with the heater produce very high THD% levels ,20% and above,for that I don't think there is a remedy.
Maybe another set of measurements to clear that up.
But not yet! we should first agree about what tests to do before .
What is the generator you are using(Brand and Model) ?
If possible ,please post a datasheet of it as well.
Normally I'm not as sloppy as I've been in the execution of the various tests and usage of the software + dongle (12v +2 resistors). What happened is that testing could only be done with the gen located outside the house and with forecast of rain for days to come, it left me a bit frenetic. If I would have not been dependent on the weather, I would have taken the time to read the manual that came with Soundcard Scope and educate myself a little bit more in matters related to the technicality of electricity.
2) That is due to a misunderstanding on my part. I looked at your attachment and I thought both waves had to fit perfectly one on top of the other. I can either select only one or do ch1+ch2 which results into a single wave. Which one do you prefer, single or ch1+ch2?
3) Yes I believe I saw something related to that when I was quickly browsing the manual.
4) I'm not sure if I misunderstand you here. You talk about gen at idle in post 28 looking different than in post 30. But I didn't post pics of gen at idle in post 30. Maybe you do not need pics at idle from both posts to make such comparison???
For the sake of clarity and this is something I was going to write about later; I have two identical generators. Bought the same day and both having gone thru nothing more than the 5 hour break-in period. On top of that, I can even tell you that they were both manufactured the same day in that factory in China. Post 28 was done using gen1, while post 30 was done using gen 2. Though I can tell you that when I did the break-in, I used a kill-a-watt and found that gen1 was peaking at 63Hz, while gen2 was peaking at 62.5Hz. As you apply a load, the Hz moves down towards 60.0Hz. With a 1500W load (the gen is a 3000W continuous) the Hz was about 61.5Hz.
Another preliminary observation is that when the Asus netbook was giving me a THD of 5.0% for home electricity, the Toshiba laptop was giving me 5.5% THD. But this is very preliminary. I noticed that the THD changes depending on the time of the day. During daytime when my neighbors are at work, THD can be found in the 4% to 5%. But when it is around 5pm+, it reaches 5% to 6%. So maybe the higher reading of the Toshiba was only due to the fact it was later in the day.
As part of my future tests, I will observe the line-in and mic ports of the desktop for 15 minutes each and then use the Toshiba laptop also for 15 minutes in order to compare possible variations.
The importance of THD is only in relation to possible damages to appliances and other electric/electronic equipment. If THD is 20% but the heater or electric motor can take it then it's fin with me. I intend to use an inverter (not tested yet) for anything like my furnace with an ECM motor and other sensitive things, like TV, PC, battery charger, etc. I just would like to know if a high THD might damage motor/compressor for say, a 10 hour run during a blackout.
I would be interested to hear about any possible remedy. Maybe I could build one and test it with the gen.
Definitely, we will need to go over details of the next tests before I execute them. And also make sure you are satisfied with the info I'm getting you out of Soundcard Scope.
As to the specific generator I was using, please go to http://www.championpowerequipment.com/products/generators/for-home/100215-3000w3750w-generator/
. You can also search the web, but I doubt you will find a great deal more info about it.
What I did yesterday is plugged two chest freezers and a fridge and I ended up with a THD of 7.25. Which is just under the acceptable limit of 8% and can still be considered good. That was the purpose of the propane gen, to be able to run those three things, plus maybe a few small lights and doing it on propane means no hassle with storing gasoline. And it burns so much cleaner than gasoline. Btw, when the 6.5 amps rated motor of the fridge started, the THD jumped to 23 for a second or two before dropping back down to 7.25 (I already had the two chest freezers running when the fridge was added).
There is a long weekend coming and I don't know my schedule yet, so you might not hear back from me until possibly next Monday.