Power Quality of Generators Sine me up!

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Jooksing

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There is a bunch of cheap generators on sale and I want to see how "clean" the electricity is. I have had a number of electronics go bad using the cheap car 12v power inverters. This is the website that intrigued me.

http://www.jkovach.net/projects/powerquality/

I picked up a cheap 1000w Sportsman inverter generator for $157 at walmart and wanted to see how "clean" it really is. I bought a cheap oscilloscope (a silly scope as the wife puts it) that required me to self solder it together - JYE tech DSO150

So I measure a number of power sources around the house. I still plan to test them with different loads (lights/motors etc) on it.
This is my typical set up. using a "wall wart" to bring the voltage to safe levels. I also used a 10x probe to lower it more. The Oscilloscope is powered by batteries to add a safety measure of self feeding live mains.



This the the reading of the power company, not sure why there is a small distortion to it - could be something using electricity in the house back feeding noise.


Cheap Inverter generator looking clean! I also attached a fan to it and it looked the same.


This one is my "regular" 4k generator. Notice the sharp peaks.


Cheap car inverter - 400w Peak brand


Belkin backup power UPS. This units is about 15 years old that is now connected to a deep cycle battery. Sorry for the shaky hands.
 
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The eagle River also gave a lot of electrical noise by proximity. Just being near it and not connected my scope had bouncing lines.
 
What kinds of loads are you putting that scope on? Wonder if a nice 100 watt incandescent light would smooth it out any.
 
No loads yet.. that's for next round. I was thinking LED light, incandescent, fan... Something like a "feet" vibrator... Some thing that usually put a buzz on the radio...
 
Originally Posted By: zzyzzx
Exactly what is a "inverter generator"????


That's one of the more modern generators that's a bit more complex than just an engine-driven alternator. There's an alternator all right, but it's a high frequency unit that can be more compact. The voltage it generates gets rectified into high voltage DC, then it uses a DC to AC inverter to drive the output. There's usually some smart circuitry and a servo driven throttle on the engine, so the engine can throttle down for light loads. The advantage is that for small loads, it can be more efficient than a conventional one that's always running at 3600 RPM. They are also less at the mercy of a cough or stumble on the engine because the speed of the engine does not directly affect the frequency or waveform of the output.
 
Originally Posted By: Dave Sherman
Originally Posted By: zzyzzx
Exactly what is a "inverter generator"????


That's one of the more modern generators that's a bit more complex than just an engine-driven alternator. There's an alternator all right, but it's a high frequency unit that can be more compact. The voltage it generates gets rectified into high voltage DC, then it uses a DC to AC inverter to drive the output. There's usually some smart circuitry and a servo driven throttle on the engine, so the engine can throttle down for light loads. The advantage is that for small loads, it can be more efficient than a conventional one that's always running at 3600 RPM. They are also less at the mercy of a cough or stumble on the engine because the speed of the engine does not directly affect the frequency or waveform of the output.


Conversely, a standard 3600 rpm generator has a better flywheel and can chug through a sudden increase in demand better, such as a motor starting up. Such a motor doesn't care if it's seeing 58 Hertz for a second or two.

Inverter generators trip on fairly innocuous faults which can be annoying if you're left in a dark house during an outage.
 
Originally Posted By: Ducked
Originally Posted By: Jooksing
I got it from Amazon because of the quick shipping and the extra probe.
https://www.amazon.com/gp/aw/d/B06Y1T6WZ9/ref=ya_aw_oh_bia_dp?ie=UTF8&psc=1


If you have wait much cheaper here. (Expect 1-2months)
https://m.banggood.com/Orignal-JYE-Tech-...ml?rmmds=search


Blimey! $15 for an oscilloscope!

How difficult to assemble? Instructions adequate for a non-electronicist?


Online instrs and documentation look OK to my inexpert eye. No Chinglish in sight.
 
Originally Posted By: Jooksing
No loads yet.. that's for next round. I was thinking LED light, incandescent, fan... Something like a "feet" vibrator... Some thing that usually put a buzz on the radio...
You really should load it first before meas or analyzing sine wave distorsion. For a further test, have a look at the current waveform distorsion...

I did similar experiments several years ago with a Fluke 43B power quality analyzer. Fantastic instrument. (The in-rush surge on a buddy's 12" Dewalt radial arm saw was >100A! I told him he should seriously consider re-wiring it for 220Vac).
 
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