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Picked-up a cheapo (300A A/C - 450A DC) current probe with BNC to look at various start-up currents (and also for general automotive applications). Connected to scope and played around with an elec space heater and an incandescent 60W light bulb this evening.

After resolving some scaling issues, everything is working as expected with 1 exception. When I measure the current with the scope, it measures too high compared to 3 other instruments I have. The trace apparently represents peak current. I have a Measure button on the scope and if RMS Current is selected, I get a good current reading in the little box at the bottom. Gave up trying to get trace to display RMS current. Found that if I multiply the RMS value by the sq root of 2 (1.414) I get the same value as the trace shows on the reticle. Conversely, if I multiply the peak current by .707, I get the RMS value. (BTW, this only works for a pure sine wave)

The Measure box displays the RMS current but does not capture the first few large peaks, thus why I needed to be able to convert peak current to RMS current,,, I think..

The point of all this is to get a good baseline on my A/C and well pump start-up currents on city power, then compare to genset power. Question is; when genset manuf claims peak current, are they referring to actual peak current or peak RMS current?? I'm leaning heavily towards peak RMS current.
 

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I would say it's all in RMS.

The 120V | 240V AC standard is in Vrms. These are actually 339V | 678V p-p.

It would follow then that the current is also written as RMS values. "Peak current" in the context of a generator's capability to support transient heavy loads would be the max Irms over a relatively short amount of time.
 

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also it might depend on the hz detected.
if it is an inverter some where in there it maybe spurs of another FQ and not the 60 hz.
a spectrum unit is handy when looking at power quality.
but pricy. for the good units.

and lol on the peak power in the old and new car audio!
the heck of it is the new stuff is even worse!

you need a lab test bench just to see what you have before connection.

i like the kenwood excelon series in the late model car audio stuff.
good quality for the bucks.

pm if you need links!
i went the better 2022 media player with XM for the head unit.
working on the system a little at a time.
7 inch on the door speakers as excelon
and plan on the same in the rear hatch location.
thinking a single 12 for the sub with a mono amp.
for just a bit of bump on the bottom end.
it should sound as good as the home theater when i get done.
and about $1200 for the whole system for materials

just like doing a gen system a little at a time on the parts you tend to not miss the money.
lol!
the gen system here is way over $30k in time and materials.
but it is handy to have!
and if you do it right it will last 10-30 years.
 

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lol.. is this now a car audio forum? Chalk one up for another Kenwood fan here...

Have my flagship DDX8034BT from 2009 with all the bells and whistles of the time... Analog NTSC TV module (now pretty much unusable), Garmin module for Nav (backup to my Waze app), and an iPod integration kit connected to an iPod Classic 120GB (as backup to my Roku and Alexa with Spotify). It's been through two vehicles and still working like new.

Anyway, to this day, I still see "2,000W P.M.P.O." boom boxes being sold (which probably have like a 30 or 50W amp, at best). No longer behind white unmarked vans but usually from shops near Chinatown. No surprises there.

As not to be too off-topic, inverter generators are the future... no doubt about it. I am generally impressed with how it can maintain a perfect sine wave under any load condition... which then lends to its very low THD. I will eventually switch to one, just not yet.
 
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