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Wow. That is cool.

When manufacturers put out their THD data, it may be based on a no-load condition. If so, is that a valid value to believe if a load causes three times the distortion?

After all, a high THD wouldn't hurt anything if nothing is on the genset, and a low THD doesn't help anything if it's only when there is no load.

In any case, I don't remember seeing equipment being reported as damaged by gensets with high THDs. I have seen reports that some appliance may not run on a particular genset, but that doesn't mean it was damaged in the trying. If some vital appliance doesn't run, then either get another genset or another appliance.

Interesting data. Thanks!
 

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Wow. That is cool.

When manufacturers put out their THD data, it may be based on a no-load condition. If so, is that a valid value to believe if a load causes three times the distortion?

After all, a high THD wouldn't hurt anything if nothing is on the genset, and a low THD doesn't help anything if it's only when there is no load.

In any case, I don't remember seeing equipment being reported as damaged by gensets with high THDs. I have seen reports that some appliance may not run on a particular genset, but that doesn't mean it was damaged in the trying. If some vital appliance doesn't run, then either get another genset or another appliance.

Interesting data. Thanks!
If you guys think UPS systems deliver clean power, this is scary!
I know that the double conversion UPS units are top of the line but, so many of us out there own the Line Interactive UPS units.
I have two, one is a CyberPower 1500VA AVR, the other is an APC 1500 Back-UPS XS.
I will test the APC later.
This test was performed using a Fluke 345 Power Quality Clamp Meter.
Testing was done with three laptops connected and the power cord pulled from the outlet.
CyberPower 1500VA AVR.jpg
CyberPower 1500VA AVR THD.jpg
 

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That looks like the patterns I've seen for non-pure sine wave inverters popular with campers. They seem to operate many things without problems. I've run small refrigerators and such with them. Some things that won't work with them are at least some microwaves and, of all things, electric blankets. But this type inverter is popular because they cost a fraction of the pure sine wave units.

Your new Fluke is going to give us a lot of interesting information if you keep this up. I'm wondering how those inverter gensets fare on the screen.

Thanks!
 

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That looks like the patterns I've seen for non-pure sine wave inverters popular with campers. They seem to operate many things without problems. I've run small refrigerators and such with them. Some things that won't work with them are at least some microwaves and, of all things, electric blankets. But this type inverter is popular because they cost a fraction of the pure sine wave units.

Your new Fluke is going to give us a lot of interesting information if you keep this up. I'm wondering how those inverter gensets fare on the screen.

Thanks!
Thanks, I have a lot of uses for the new meter.
I will be testing the Champion 6250-Watt Open Frame Inverter generator once the weather clears up again.
The line interactive UPS units have their place. I wish I had a double conversion pure sine wave UPS to test.
It will be interesting to see How the APC does, It only has a modem, router and a 2-bay NAS connected to it.
I may also test the CyberPower with no laptops connected, two connected and one connected to see how that influences the THD output.
 

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Loads placed on the generator can profoundly impact power quality on the system in various ways, some good and some bad: resistive, inductive, reductive, capacitive, whatever.

Some loads can be like the drunk uncle at a Christmas party; others like Mother Theresa at a christening.

So, are we being too anal about surfing a perfect sine wave from an expensive inverter genset when some loads can put sharks in the water?
Maybe the new Fluke can tell us. :)
 

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Loads placed on the generator can profoundly impact power quality on the system in various ways, some good and some bad: resistive, inductive, reductive, capacitive, whatever.

Some loads can be like the drunk uncle at a Christmas party; others like Mother Theresa at a christening.

So, are we being too anal about surfing a perfect sine wave from an expensive inverter genset when some loads can put sharks in the water?
Maybe the new Fluke can tell us. :)
I have many tests planned for resistive, inductive, reductive, capacitive as you said. All I need is time.
I will post results if found to be of interest.
 

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THD in excess of 50%? That's rather dreadful. I wouldn't want to run anything on that kind of power.
It is unfortunate that these companies market the UPS units such as these for keeping your computers and such on line during a power outage.
I've been using them for years with no adverse effects though. My testing was an eye opener though!
 

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Your results seem to verify the assertions made by this poster or source, the origin of which I've lost in my chaotic world somewhere:

"Now, lets talk about UPS (uninterrupted power supply). The majority of UPSs, especially ones that cost under $20,000, simply represent a large non-linear power supply to their AC source. Just like the SMPSs, they wreak havoc on the AC power quality of their source. Someone mentioned 'double-conversion' UPS. Nice; but clueless. (Sorry.) The output of a double-conversion UPS is almost always much, much poorer than the AC source sine wave entering it. They use PWM (pulse width modulation) or some other method to convert the DC back into AC, resulting in one of the most choppy 'sine waves' one could ever see. Yeah, they ensure the voltage doesn't drop when their input does, and they filter transients, but that's about all they do. Aside from that, the power quality of their output is horrible. Again, anything under $20,000 and the output is going to look more like a square wave than anything. Add capacitance of the circuit, and its much poorer than that. The majority of low-cost UPS equipment (under $20k) chop their output into three squarish-looking chunks each half-cycle. You have to pay big bucks to get a 12- or 18-pulse UPS with adequate input and output filtering. But all this is not a problem, because 99% of the time, the SMPS equipment that is connected to UPS systems doesn't care one bit."

Addendum: SMPS = switch mode power supply, like what is found with laptops, etc.
 

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I have many tests planned for resistive, inductive, reductive, capacitive as you said. All I need is time.
I will post results if found to be of interest.
Oh yeah, I'm sure there is interest in these tests! After all, the intensive discussions that are taking place about inverter gensets being necessary for today's "sensitive" electronics are of great interest to many.

Personally, I haven't seen such a need yet, since all of my old gensets are non-inverter types and haven't hurt anything yet, I don't think :-/

So, what can be revealed by Mr Fluke :) through your tests has to be of interest to many.

Thanks for your contributions to us Gen-Heads!
 

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Your results seem to verify the assertions made by this poster or source, the origin of which I've lost in my chaotic world somewhere:

"Now, lets talk about UPS (uninterrupted power supply). The majority of UPSs, especially ones that cost under $20,000, simply represent a large non-linear power supply to their AC source. Just like the SMPSs, they wreak havoc on the AC power quality of their source. Someone mentioned 'double-conversion' UPS. Nice; but clueless. (Sorry.) The output of a double-conversion UPS is almost always much, much poorer than the AC source sine wave entering it. They use PWM (pulse width modulation) or some other method to convert the DC back into AC, resulting in one of the most choppy 'sine waves' one could ever see. Yeah, they ensure the voltage doesn't drop when their input does, and they filter transients, but that's about all they do. Aside from that, the power quality of their output is horrible. Again, anything under $20,000 and the output is going to look more like a square wave than anything. Add capacitance of the circuit, and its much poorer than that. The majority of low-cost UPS equipment (under $20k) chop their output into three squarish-looking chunks each half-cycle. You have to pay big bucks to get a 12- or 18-pulse UPS with adequate input and output filtering. But all this is not a problem, because 99% of the time, the SMPS equipment that is connected to UPS systems doesn't care one bit."

Addendum: SMPS = switch mode power supply, like what is found with laptops, etc.
Correct, Generac recommends sizing your generator to provide 5Kw for every 1Kw of 'double-conversion' UPS systems due to the noise they produce back to the generator.
 

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It's really interesting to see:

---the rough, square-wave pattern that the battery-powered UPS equipment is providing to the device it is protecting and servicing during power outages without the aid of an auxiliary generator;

---and then the "noise" being created for the generator and its serviced circuits when the UPS is in standby mode.

You'd never know all that is going on without seeing it on the Fluke meter and other such devices.

And those huge THD numbers. Say it ain't so, Mac.

But, on the other hand, there are no widespread reports of things being damaged by such UPS equipment or from similar devices like non-pure sine wave inverters that are very commonly used by many folks out there.

So, are we worrying too much about high THDs from non-inverter conventional generators...the ones that have been carrying the load all these many years? Or, are we so fully into the Brave New World where all the new-and-improved controlled-by-a-silicon-board equipment is so sensitive that we must provide them power from a generator that is itself controlled-by-a-silicon-board?

Interesting. Belly, Belly Interesting.
 

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I think most people use frame generators with no idea how much noise they produce, as OMH had said a few days ago. I have heard stories of people who have had issues after using non-inverter generators for a long-ish time. But that seems to be kinda rare. As an example, I have a bowling teammate who has a Predator 7K watt non-inverter that he can connect to his breaker box. He recently used it for about 4 days when we had a big outage due to a winter storm. He ran everything off of it. Fridges, TVs, freezers, the whole shebang. He told me everything worked fine, no issues whatsoever. There were a few items too big to run on it, but otherwise, nothing seemed to be the worse for wear.

So, I don't know. I'm sure the Predator power wasn't terribly clean given it was your typical frame genset. But it didn't cause any issues for him. Still, I feel better using inverters.
 

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Champion 100519 6250-Watt Open Frame Inverter sinewave and THD results here:
 

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I tried out a few different AC sources last weekend.

4375W/3500W Predator traditional generator, 1000W load, sinewave
9447


4375W/3500W Predator traditional generator, 1000W load, THD
9448


2500W/1850W Champion model 100899 (dual fuel) inverter generator, 1000W load, sinewave
9449


2500W/1850W Champion 100899 (dual fuel) inverter generator, 1000W load,THD
9450


I also measured my home power.
Sinewave. You can see the rounding off of the sinewave from power supplies that only pull power off during the peaks.
9451


THD was 2.4%
 

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I tried out a few different AC sources last weekend.

4375W/3500W Predator traditional generator, 1000W load, sinewave
View attachment 9447

4375W/3500W Predator traditional generator, 1000W load, THD
View attachment 9448

2500W/1850W Champion model 100899 inverter generator, 1000W load, sinewave
View attachment 9449

2500W/1850W Champion 100899 inverter generator, 1000W load,THD
View attachment 9450

I also measured my home power.
Sinewave. You can see the rounding off of the sinewave from power supplies that only pull power off during the peaks.
View attachment 9451

THD was 2.4%

Thanks for posting this. This is extremely useful information with different gensets.
 

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Pulsar 2200/1800W Dual Fuel Inverter Generator Model PG2200BiS, 1000W load, sinewave
9490



Pulsar 2200/1800W Dual Fuel Inverter Generator Model PG2200BiS, 1000W load, THD
9491
 
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