Inverters vs generator power???

[Roswell Bob]

I can't imagine that an inverter would produce cleaner power than a generator. Can anyone educate me?

 

[Keith C]

I can't imagine that an inverter would produce cleaner power than a generator. Can anyone educate me?

Totally agree with george's response. I'd add that most the little non-inverter generators who's outputs I've examined with an oscilloscope are putting out badly distorted sine-waves that a sine-wave inverter wouldn't have much trouble improving upon.

 

[Keith C]

Absolutely. The reason is that you need more iron and more windings to enforce an accurate sine-wave and all these little generators aim for light to carry and inexpensive so the waveform suffers.

 

[Factory400]

There is a reason that the best small generators for electronics and sensitive loads use inverters internally.

If the comparison is a typical alternator based gas generator vs a pure sine wave inverter - the inverter will win in almost every possible metric for quality. There is no real comparison - inverters are about as close to perfect as it gets. A large scale inverter system gets really expensive though. Luckily, larger diesel generators can be really good.

I used to own a generator rental business and we had large diesel based units that could provide 100-150kW or so. They had huge flywheels and alternators along with precision engine control and regulation so they were rather good. Certainly safe for any type of load no matter how critical. They were mainly used to power mobile television production trucks with $millions of worth of hardware inside. They typically cost $100k+ , however. Perhaps lower cost if you would leave off the sound-proof enclosure.

Low cost gas units have wildly varying frequency and voltage along with considerable electrical noise. No problem for heaters and lights, but it is a problem for any modern electronics.

 

[Keith C]

Totally agree with george's response. I'd add that most the little non-inverter generators who's outputs I've examined with an oscilloscope are putting out badly distorted sine-waves that a sine-wave inverter wouldn't have much trouble improving upon.

Weird. Where did all of George's responses go??! There were several in this thread.

 

[Keith C]

I find it interesting that the popular LV series of all-in-one inverter/charger units by MPP state; "You can supply this unit with a generator as long as it's an inverter generator".

 

[Just John]

Weird. Where did all of George's responses go??! There were several in this thread.

Who is George?

 

[Keith C]

Who is George?

Some guy with a picture and two long and well stated responses. Like half pages long. When I came back after mentioning him he and his posts were gone. (annoying) Maybe he was one of those Affiliate Link People Will won't tolerate and he got kicked or maybe he just took his toys and left. Weird though.

 

[Roswell Bob]

Totally agree with george's response. I'd add that most the little non-inverter generators who's outputs I've examined with an oscilloscope are putting out badly distorted sine-waves that a sine-wave inverter wouldn't have much trouble improving upon.

I see. I am aware of the distortion that can be created with a non-linear load. Peaks are squashed flat. Little generators have a lot of source impedance so lots of distortion would result. Inverters with decent control loops would have the effect of reducing the source impedance. I would imagine that toasters and other resistive loads might not mess sinewave up too bad. Are you aware of other sources of the distortion?

 

[Keith C]

Hi Rosewell Bob. I suspect you're exactly correct about the source impedance letting the loads more easily shape the supplied waveforms. There are lots of things that would tend towards distorting a little generator's output.

Of course the prior mentioned rectifier front devices every house is riddled with these days;
Wall warts
Cord warts
LED light fixtures
Fluorescent lighting ballasts
Flat panel TVs
Lots of massively overpriced refrigerators sporting VFD driven compressors
Front loading wash machines that are now all VFD driven three phase motors

However, things that aren't rectumfryer front ended and can cause little generator distortion are things that reciprocate. Stuff like air compressors and refrigeration compressors. They can cyclically draw current as their pistons are hitting the compression stroke.

The distortions I've seen tend to be the sinewave looking like mountain tops, sometimes with a side looking Mt. Saint Helens like, rather than graceful sinewaves.

 

[Roswell Bob]

Great. Yep the rectifier front ends do muck with the nice sinewaves - and yes, they're everywhere. Never gave much thought to the compressor although my washing machine tends to make lights flicker. I suppose that may be more of effect from slow inverter loop or dead lead-acid bank I'm running.

I have small 3500w Champion inverter generator that seems to do fairly well. The real test will be trying to run a 3500W charger.

thanks
Bob

 

[Keith C]

3500W isn't so small for an inverter generator (sounds like the Predator). The only thing I think is bigger is the Honda EU7000.
Ohhh a 3500W charger is probably too much for a 3500W generator. Hopefully you can dial down the charger's maximum output. The charger will likely have the dread rectifier front-end and so will try to suck the energy across just a few degrees of the line cycle which the semiconductors in the generator inverter will take a dim view of.

 

[Arbee]

While on the subject on generators that are inverter generators, in addition to clean power then can throttle the engine to match load, saving gas and noise when demands are low, by virtual of how inverter generators produce current.

 

[Keith C]

While on the subject on generators that are inverter generators, in addition to clean power then can throttle the engine to match load, saving gas and noise when demands are low, by virtual of how inverter generators produce current.

Indeed. Actually the entire point of their existence. Works pretty well!

 

[Delmar]

There are many variants of inverters: cheap vs quality, low-frequency vs high-frequency. However YouTube videos have shown the UPS inverter output to be cleaner than line power when operating on battery.