I started researching THD while learning about solar/battery inverters. What I learned is that THD comes from many kins of loads (like electronic ballasts) and has a ripple affect across the grid. The grid is large enough that THD mostly dissipates like ripples across a pond, but its stronger at the source. I've been able to measure the THD of several UPSs which use a stepped square wave to approximate a sine wave. The readings I got matched the sticker rating on each device. I also measured my house's THD from the grid and got around 3%. I live in Washington. Something to keep in mind: because THD can be caused by loads and not just sources like generators, THD will vary depending on the type of load you put on your system. Also, pure sine inverters will have a different THD depending on how much load you put on them. I did a few testes with a pure sine inverter a while back with different kinds of loads and tried to test the inverter at different percentages of it's total output capability. It wasn't particularly scientific, but at no load the inverter was below 1%, and every load I put on it cause the THD to rise between 1 and 2%. I think this is why inverters are rated with a "
A theory I've always wanted to test if i can explain well enough. A 4 cycle, single engine engine generator has to make 2 full revolutions per ignition cycle. so the engine is constantly speeding up 1 revolution then coasting until the next cycle. 3600 RPM means 60 revolutions per second (also 60Hz) and 30 ignition cycles per second. It just seems like that would cause a fuzzy waveform in my mind. I got a cheap harbor freight 8750 watt generator. The waves are ugly but I try to only load it about 50% and haven't seen any adverse affects on my stuff but I really don't like the thought of using it. More expensive standard generators seem to have some electronic regulators that probably offer some buffer and make it better and V-twin engine generators always seem to have low THD.
Back when I was a teenager/young adult (1970s) with money to burn, I dabbled with higher-end audio equipment. This was when the typical stereo equipment was often in a nicely finished wood cabinet. Harmonic Distortion was something you looked at in your amplifier, speakers, reel to reel tape player, and turntable. I researched specs, buying the best equipment components I could afford. Other audio equipment such as microphones and headphones also has harmonic distortion. As a would-be opera singer then, my ears are sensitive enough that I couldn’t listen to the cheaper equivalent for more than a short time without casu fatigue and other issues. While I didn’t pursue the sin career, and my aging ears are not as sharp as they used to be, I can still hear the interference in the cheaper headphones to this day (age 67). What is surprising is the increased quality in the off-the-shelf $20.00 headphones now vs the similar stuff from 20-30 years ago. Anyway, even though I’ve abandoned the pretentiousness associated with the “Wookie the Golden Ear” audiophile claims, I still appreciate the better quality equipment. I can buy a perfectly adequate system for my podunk little house with it’s low ceilings and weird construction without paying for equipment requiring a sec mortgage on my home.
A have a Westinghouse and it's 5 > 12000 watt and 15000 peak. I got so that I can run my whole house ac system. I paid $3200 plus tax for it. I replace an old Generac that was 15 >
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I started researching THD while learning about solar/battery inverters. What I learned is that THD comes from many kins of loads (like electronic ballasts) and has a ripple affect across the grid. The grid is large enough that THD mostly dissipates like ripples across a pond, but its stronger at the source. I've been able to measure the THD of several UPSs which use a stepped square wave to approximate a sine wave. The readings I got matched the sticker rating on each device. I also measured my house's THD from the grid and got around 3%. I live in Washington. Something to keep in mind: because THD can be caused by loads and not just sources like generators, THD will vary depending on the type of load you put on your system. Also, pure sine inverters will have a different THD depending on how much load you put on them. I did a few testes with a pure sine inverter a while back with different kinds of loads and tried to test the inverter at different percentages of it's total output capability. It wasn't particularly scientific, but at no load the inverter was below 1%, and every load I put on it cause the THD to rise between 1 and 2%. I think this is why inverters are rated with a "
A theory I've always wanted to test if i can explain well enough. A 4 cycle, single engine engine generator has to make 2 full revolutions per ignition cycle. so the engine is constantly speeding up 1 revolution then coasting until the next cycle.
3600 RPM means 60 revolutions per second (also 60Hz) and 30 ignition cycles per second. It just seems like that would cause a fuzzy waveform in my mind.
I got a cheap harbor freight 8750 watt generator. The waves are ugly but I try to only load it about 50% and haven't seen any adverse affects on my stuff but I really don't like the thought of using it.
More expensive standard generators seem to have some electronic regulators that probably offer some buffer and make it better and V-twin engine generators always seem to have low THD.
I like the inverter style for the low THD, but they are much more expensive
Back when I was a teenager/young adult (1970s) with money to burn, I dabbled with higher-end audio equipment. This was when the typical stereo equipment was often in a nicely finished wood cabinet. Harmonic Distortion was something you looked at in your amplifier, speakers, reel to reel tape player, and turntable. I researched specs, buying the best equipment components I could afford. Other audio equipment such as microphones and headphones also has harmonic distortion. As a would-be opera singer then, my ears are sensitive enough that I couldn’t listen to the cheaper equivalent for more than a short time without casu fatigue and other issues. While I didn’t pursue the sin career, and my aging ears are not as sharp as they used to be, I can still hear the interference in the cheaper headphones to this day (age 67). What is surprising is the increased quality in the off-the-shelf $20.00 headphones now vs the similar stuff from 20-30 years ago. Anyway, even though I’ve abandoned the pretentiousness associated with the “Wookie the Golden Ear” audiophile claims, I still appreciate the better quality equipment. I can buy a perfectly adequate system for my podunk little house with it’s low ceilings and weird construction without paying for equipment requiring a sec mortgage on my home.
from the '70s till now, It's wild how the tech game has shifted and how it's impacting the way the youngins vibe with music today.
A have a Westinghouse and it's 5 > 12000 watt and 15000 peak. I got so that I can run my whole house ac system. I paid $3200 plus tax for it. I replace an old Generac that was 15 >
Awesome!
How do you measure THD
A THD meter, but it's not worth buying. They are very expensive.
ruclips.net/video/n5Zxvk7tiC4/видео.html
Good video. Do some exploring!
THD should be listed in the equipment specifications.
@leestokes6761 hard to find on some equipment. I figure if it's low, they'll make it easy to find so they can brag 😀
@@abrelectric it's kinda like they don't want you to 👀 know 👀the THD levels