And less THD than mains power, to boot. I use the older, carburated EU6500IS, and it's a gem.
Whose testing gear were you using to see/read THD?
Also do you have an industrial plant w/robots on your Feed line?
Ken:
An oscilloscope with FFT - I have few. Very handy for checking mains power quality.
On mains power, flat-topping of the AC wavefore is visually obvious and quite a few interesting spurs show up. This varies a little bit with home loads and AC outlet choice - but not a lot. I've watched this problem develop quite a bit over the last decade.
Plenty of neighborhood switch mode power supplies and inverters out here, both drawing from the mains power grid (like variable speed A/C units and electric car chargers - both very popular out here) and feeding into it - like solar installations. Use of this technology has expanded geometrically, and as it has, power quality has dropped.
I currently have four generators ( and have had more over the years) at three homes. Three generators are Honda inverters and one is a mechanically governed, electronically regulated "traditional" generator (Generac 4000XL).
The Honda inverter generators simply work, every time and produce visually perfect waveforms. There are some higher frequency spurs visible in the FFT, but these have never been a problem. When I switch (most) of the CA home over to the Honda EU6500is, all of the office loads, computers, lights (LED - very non-linear) and ham station come back on line. Inverter EMI/RFI noise does not seem to be an issue for radio operations, perhaps because my Astron linear supplies make pretty good low pass AC line filters. And at the house outlets, the waveform is very clean.
When operating the radio on portable ops, I've run off of the tiny EU1000is and sometimes attach a compact IEPS 12A line filter when operating below 40M. Noise has never been an issue - electronic or audio.
The Generac 4000XL - an older model from before their breakup/sale and reconstitution, is a pretty good little unit, too, with an OHC engine, full pressure lubrication, a Toyota Corolla compatible spin-on automotive oil filter, adjustable electronic voltage control and a mechanical governor. THAT pupply is 20+ years old, has given very good service but has plenty of visible distortion in its waveform - always has - nowhere as clean as the Honda inverters. And the generator head exciter is brush-fed rather than induction driven (which has even more distortion). The Generac also burns a lot more gas, though it was quite good for its day.
Out here and in Hollywood, the EU6500is generators have been standard fare for powering Kino lighting (VERY demanding VERY non-linear loads) for MANY years and tests show less than 3% THD. See link below. They usually have a pallet of them (and the Kino lights) on a flatbed just over at Manhattan Studios (AKA Marvel) just down the block from me and trundle them over to whatever local on-location shoot they're doing for the day.
http://www.screenlightandgrip.com/html/hd_plug-n-play_pkg.html BUT.... CHEAP inverter generators are like anything else. The Hondas (and I hear the Yamahas, too) work very, very well and provide exceptionally clean power, use little fuel and are RELIABLE. So... PLEASE do not come back with a reply that says: "My Harbor freight POS let me down (or works better)", or that a Coleman or other late to the game inverter generator with Chinese electronics ... is not so good because its an inverter, or is better at 1/4 the price, etc.
I've used generators for years, and the survivors are the Hondas and one (very old) Generac. Tried the cheapo brands and know just how BAD they can be, when you really need them. During the recent winter storms in CT, my cousin just walked over to my place and borrowed the little Honda EU2200is to power his fridge, lights and a gas heater blower after his Brand X POS died within two hours of use. The Honda ran just fine for three days.
I don't know what Dereck's (KF5LJW) bad experience with inverter genertors has been, if any. I'm going to bet that his site backup needs, if portable at all, are more in the MQ Power class of big diesel generators, that BEGIN at 8KW and go up, far beyond where the EU6500is leaves off.
But I'd like to hear his story, too.
Brian - K6BRN