Non-Inverter Gen with an AVR (Automatic Voltage Regulator)

[MarkF48]

A non-inverter generator does put a sine wave, but due to fluctuations in the speed of the engine the voltage output can vary as well as the frequency a bit. I'm guessing it would be the voltage variance that some pellet stoves don't like and not so much the small frequency changes. I tried this with my own 3200w generator and monitored with a Kil-A-Watt meter. The generator nominally put out 116vac with no load and when I put on a 10 amp load dropped to about 112vac. The frequency remained within about 1 hz or less from a nominal 59.8hz.
I came across a couple AVR's that would regulate the output voltage for a fairly wide range of input. I believe either would be able to carry a pellet stove load easily including the ignitor.
Anyone using one of these?

APC LE1200 Line-R 1200VA Automatic Voltage Regulator
Amazon product ASIN B00009RA60
Tripp Lite LC1200 Line Conditioner (also provides surge protection)
Amazon product ASIN B0000512LA

 

[Dataman]

It seems a Risk to me. For the risk price you can get Inverter Generator. Then no risk. Try it and let us know when you can afford to do without the Stove

 

[Golfeur]

APC LE1200 Line-R 1200VA Automatic Voltage Regulator
it will correct the voltage but it will not correct the frequency which is important

 

[scajjr2]

A non-inverter generator does put a sine wave, but due to fluctuations in the speed of the engine the voltage output can vary as well as the frequency a bit. I'm guessing it would be the voltage variance that some pellet stoves don't like and not so much the small frequency changes. I tried this with my own 3200w generator and monitored with a Kil-A-Watt meter. The generator nominally put out 116vac with no load and when I put on a 10 amp load dropped to about 112vac. The frequency remained within about 1 hz or less from a nominal 59.8hz.
I came across a couple AVR's that would regulate the output voltage for a fairly wide range of input. I believe either would be able to carry a pellet stove load easily including the ignitor.
Anyone using one of these?

APC LE1200 Line-R 1200VA Automatic Voltage Regulator
Amazon product ASIN B00009RA60
Tripp Lite LC1200 Line Conditioner (also provides surge protection)
Amazon product ASIN B0000512LA

From watching James Condon's videos on YouTube (he repairs & refurb's a lot of generators), adjusting the governor helps keep the voltage and Hz stable. He usually tests the gennys with a couple 1500w space heaters hooked up.

sam

 

[gfreek]

Is there an issue with putting a heavy load on a generator creating a dip or spike while powering sensitive electronics ?

 

[Highbeam]

US utility voltage is allowed to vary quite a bit. Your harman won’t care if it’s in the allowed range. Frequency is more important.

 

[rickwai]

I was always told the square sine wave was the problem from standard generators. Inverters produce the smooth sinewave like the power company. Voltage can be from 110-125V

 

[zrock]

as long as your voltage does not dip below 110 give or take a volt and go higher than 125 you should be ok. Most voltage fluctuates at that anyway. I used to work at a campground/modular park and from one side of that park to the other their was a 10v drop in the lines. Talked to hydro and several electricians over the years and they said it was nothing to worry about and that's normal.

 

[peakbagger]

Square or notched waves cause all sort of havoc, early in the solar era, most off gridders used modified sine wave inverters as they were far cheaper than pure sine wave. The editors of Home Power, the now departed magazine for solar kept a running tally of what AC appliances would run on modified sine wave units and generally the more electronics in the unit, the less likely it would run. Newer equipment now use switching power supplies that can be quite tolerant of dirty power but also can be bought cheap from 3rd world sources to keep the cost down and they can be far less tolerant.

 

[Golfeur]

With hydro when the demand is normal the voltage is at 120 volts but when it is very cold and the demand is high the voltage can drop to 112 volts. The frequency remains at 60 cycles.
There is no problem even if the voltage is at 112 volts because it is stable all the same and as the demand drops the voltage will rise to 120 volts gradually but without rapid variation, it can go up by 1 volts per hour and always remains at 60 cycles so we can say that it is a power supply that will not affect sensitive electronic equipment

 

[MarkF48]

Digging a bit further into this the issue isn't too much the generator voltage and frequency which does stay in a mostly acceptable range for a pellet stove, but that depending on the generator it may produce harmonics (multiples) of the fundamental frequency (60hz) that may cause problems or failures of certain equipment that present non-linear loads such as some electronic devices. The specification for the harmonics produced by a generator is usually %THD (percent total harmonic distortion). Unfortunately many manufacturers may not include this spec in the manual or elsewhere. I couldn't find this number in the Sportsman inverter generator I just got either, but I guess there is an assumption that since it's marketed as a pure sine wave inverter generator the THD should be low or within IEEE guidelines.
This is a well written article about THD as related to generators...

Total Harmonic Distortion (THD) – What It Is & What It Does

What are harmonics and Total Harmonic Distortion (THD)? What are the causes and effects of harmonics? Portable inverter generators allow use of clean power.

generatorbible.com

The AVR's I was looking at would have stabilized the generator voltage, but not the frequency which doesn't vary much, nor the THD which at the time I wasn't thinking about.
If I get a warm day and some ambition I may take a look at the output of my Troybilt 3200w gen with an o-scope to see what the waveform looks like no-load and with load.

Golfeur......
The regulation of frequency at this hydro (built around 1909) is/was done with a mechanical govenor and was usually dead on. This pic was around 2004 and assume it's still about the same)

 

[Golfeur]

pure sine wave generators are specified less than 3% thd

 

[Pelleting In NJ]

Mechanical generators generally produce very low distortion sinewaves...just the nature of the beast. No stove is going to have an issue running on a mechanical generator, they generally are not too pickey about a frequency or voltage variance.

 

[MarkF48]

Ok I took a look at some waveforms of the house line supply AC, my Troybilt 3200 watt generator, and the Sportsman GEN1000i. Rather than lug the O-Scope outside to the generators, I ran a 50 ft 14 awg extension to the workbench where the O-Scope resides which is probably more realistic as a pellet stove might be run off an extension and also takes into account the voltage drop of the extension cord. A bit chilly outside when I did this also. Volts and watts were recorded from a Kil-A-Watt P3 P4400 meter.
Each source was recorded with no load and then an electric heater (resistive linear load) was used as a load and the data recorded. The heater load watts did vary a bit as it heated up which accounts for some difference as well the difference in the voltage between each source when loaded.
The Troybilt generator I had thought would have a cleaner waveform, but did get better with loading. The Sportsman inverter generator as expected was squeeky clean and almost looks better than my AC house supply .
I had originally bought the Troybilt generator to power other devices during a power outage and not the pellet stove as I have a coal stove which carries the house if I don't or can't use the pellet stove. The Sportsman inverter generator was too cheap to pass up and does give me the option to power the pellet stove if I should want to as well as other devices. The Sportsman also uses a fraction of the gas for the same runtime as the Troybilt.
Different generators like the Troybilt may yield different sine wave harmonics, so this test is only applicable to what I performed it on. Given the results of these findings it could be risky powering a pellet stove or other device with sensitive electronics off a standard portable generator. Proceed at your own risk .

 

[Golfeur]

good test that says it all MarkF48

 

[Pelleting In NJ]

I stand corrected....thank-you for doing this test.

 

[Highbeam]

The famous notchy modified sine wave is produced artificially by cheap inverters. The "noisy" electricity is from cheap mechanical generators. Even though the mechanical genset makes noise its waveform is more sinusoidal because it has basic rotating rotors and magnets not terribly unlike utility generators.

 

[rickwai]

So I wonder how the Generac whole home units are? Im sure they are not inverters? My parents had one installed a 16KW. I asked the sales guy if it was clean power and he said yes much better than portable generator. He had no technical detail though

 

[peakbagger]

My guess is the generac is a conventional generator, pretty rare to see inverter generators in that size as the power electronics get pricey.

 

[Pelleting In NJ]

Generac home standby generators are conventional motor driven generators. Generac specs them as 5% maximum THD (distortion).

 

[rickwai]

My guess is the generac is a conventional generator, pretty rare to see inverter generators in that size as the power electronics get pricey.

That is what I assumed. They must be much higher quality than portable generators. There is nothing saying to turn off sensitive electronic stuff.

 

[Ocelot]

I've wondered about my own non inverter generator that backs up half my house if needed. I do also have a pure sine inverter generator I could use if needed.
I'm not really concerned about my standard generator power powering my Harman P43 because my pellet stove is plugged into a high quality APC 1000 Smart UPS. The UPS has very good voltage regulation and if I remember correctly also conditions power. Plus, it will run the stove for close to an hour without even using the generator which covers 90% of our pretty rare power outages anyway.

I no longer have my scope so I can't test the UPS output while on the generator, but that was a good idea.