Depends upon what you're trying to power.

For a lot of stuff, it doesn't matter. But increasingly, the electrical devices and appliances we find in our home are microprocessor-driven. And many of those devices can be damaged - or may not work at all - with "dirty" (high levels of THD) power. And most non-inverter generators produce fairly high levels of THD. They're also not nearly as consistent in terms of voltage and frequency.

Utility power is quite clean in most places. A good inverter generator is the closest thing most of us have to replicating that.

 

As Jager stated, it depends on what you're trying to power for the reasons he listed. The inverter gens not only have lower THD than a conventional gen (there are a few 5% max THD conventional gens), but include additional features.

For a conventional gen, you don't have the same economy mode fuel saving feature. An inverter gen can throttle down when in ECO to conserve fuel while still providing the correct output frequency and voltage to the load(s). However, a conventional gen that is running in ECO mode (if it has that feature) cannot supply any loads with correct voltage and frequency.

Another advantage to inverter gens is that they can run out of fuel...and yes it happens to all of us...and not damage the loads. An inverter gen will just shut off the load much like a switch/breaker does if the gen is running out of fuel. A conventional gen has the possibly of damaging the loads as the output frequency and voltage swing wildly as the gen is dying.

Starting an inverter gen will also supply clean power when it turns on. The inverter waits for the frequency and voltage to stabilize and then it "switches" the output power on. Conventional gens do not do that.

Inverter gens are often quieter than their conventional counterpart mostly because of the ECO feature.

If you are trying to spend less, then consider an open frame inverter as they cost less than an enclosed gen. An open frame is louder since about half of the noise comes from the engine and the other half from the exhaust. If you are considering a gen shack, then an open frame gen can be made as quite as an enclosed gen.

 

Here are the pros and cons as I see it.

Pros:
-Clean power as mentioned - I am concerned since I have inverter drive heat pumps that are sensitive to dirty power.
-More fuel efficient
-Quieter, even open frame units
-Can be paralleled if more loads are needed which is nice

Cons
-More costly
-More complex and difficult to repair - Electronics are often not easily repaired by the end user where a simple open frame model is much less complex to service.
-Typically doesn't have a huge peak load capacity when compared to a traditional gen. My parents have a 5500 watt traditional gen with an 8500 watt peak (55% larger peak). I have an 8000 watt version with a 13500 watt peak (69% larger peak). My inverter has a 6100 watt running rating and 7600 watt peak (only 25% larger peak) when being run on gasoline. I have never seen inverters with the peak output of the older style gens. This has been useful to me in the past but my newer heat pumps start on the inverter just fine as there is no surge of demand when starting like a traditional on/off compressor.

If you are not concerned about dirty power and have simple appliances such as refrigerators, etc. with a mechanical thermostat, stove/oven with turn dials and no electronic controls, you are probably good with a cheaper traditional gen. If you need clean power and want it to be as quiet as possible, an inverter is the way to go.

I bought this unit Amazon.com

My reasons were cost, ratings, and features offered. I wanted the dual fuel capability of propane and a quiet inverter around this size. My power has been going out for between 4-8 hours pretty regularly since I purchased this and the gen has served my needs quite nicely. I can run everything I need including the well. I cannot run my on-demand water heater because it is on 2x 40 amp circuit breakers. That thing really pulls a lot of amps so I would need something quite large to handle that. Unless these power outages keep it up, I won't make that jump and either not have hot water or buy a small heater which I have considered. I would be needing at least a 25kW gen for that!

Conor

 

The whole "clean power" thing is just marketing. The only real advantage to an inverter style generator is that they are significantly more fuel efficient when a large generator is running small loads.
When the average homeowner hooks up something like a 6000 watt generator to their home during a power outage, that generator spends most of its time putting out maybe 1000 to 1500 watts keeping fridges, freezers, and a television running. When someone makes coffee and runs the microwave, it ramps up into the 3000 to 4000 range and earns its place, but for the most part, it spends most of its running life producing less than 20% of its rated load. Generators run most efficiently at 80%, which is where engine fuel use vs power output is at the top of the efficiency curve..
A standard 6000 watt generator wastes a lot of fuel keeping a television and a few lights running.. This isn't the case with an inverter generator as they can vary engine speed to match load requirements.

As far as cleaner power is concerned? Its over-hyped marketing. Sure, the inverter style does produce cleaner power... absolutely, but its not that important. With few exceptions, modern appliances with microprocessors have their own built in power supplies. The USA isn't the only country on the planet, and the appliance you buy at the big box store in New York is going to be roughly the same unit sold at some retail outlet in Brazil, South Africa, Europe, Australia, or Yemen.. they're all made by the same few factories in China, and they are all designed to operate under various grid conditions worldwide.

Some of the drawbacks of inverter generators are as follows: 1) They are much more expensive than regular generators 2) Your "emergency power" source is now a few orders of magnitude more complex, which can also mean less reliable since a lot more to go wrong.. 3) When something does go wrong, you have almost no chance of fixing it yourself.

The benefits are 1) Significantly more fuel efficient 2) Much quieter when not running at full power.

I considered purchasing one, but after careful consideration, when we go into emergency mode around here, the last thing I want is to complicate it.

 

Cool, a contrary opinion. I like that.
One thing I was considering was getting a few line or power conditioners instead of an inverter generator with the saved money if needed. Might be helpful for utility power also which isn't a perfect sine wave either. Not liking the idea of more boxes around the house.
For electronics I have oil boiler with electronic controls (Viesmann with outdoor reset), a few laptops that run off transformers, cable modem, WIFI router. We rarely use the TV. I have an in-law apartment basically doubling appliances, 2 ovens, 2 electric dryers, 2 microwaves, a 3 ton compressor for AC and under 1kw of blower and controls.

 

I think the key thing with non-inverter gen's is keeping it well maintained so the engine is running as smoothly as possible.

 

Sorry, but that has nothing to do with dirty power from a generator. You cannot tune THD out of a generator.

 

The whole "clean power" thing is just marketing.

Nope.

Also, many on this forum have shared issues they’ve had with UPSs when using non inverter generators.

My UPS units on non-inverter generator power:

 

Nope.

My UPS units on non-inverter generator power:
View attachment 17050

Then you either have a poor quality UPS or one with a defect or malfunction.

I have three APC UPS's in my home.. tiny ones.. the kind you buy at Best Buy or something.. an APC UPS 750 PRO and two smaller units.. One was given to me, two others were salvaged from someone's garbage. All three work just fine when my Coleman Powermate 6250 generator is running..

I can also power my home from solar using the grid-tied array, a lithium battery pack, and two very expensive SMA Sunny Island off-grid inverters.. They work with the Coleman generator input just fine as well.

If your UPS's are throwing a hissy fit on a regular generator then you either have a wiring issue (ground loops?), a defective UPS, or the voltage/frequency of your generator needs adjusting.
And since you indicated "Units", meaning they all have the same problem, then I would tend to lean towards improper wiring or a generator that needs maintenance.

 

Nope.

My UPS units on non-inverter generator power:
View attachment 17050

Mine too, but my UPS is a gen-friendly Online UPS

Sorry, but that has nothing to do with dirty power from a generator. You cannot tune THD out of a generator.

It stops the volts jumping so much if the engine is running nice and smoothly, so surly this improves the THD a little without so many voltage spikes, no?

 

It stops the volts jumping so much if the engine is running nice and smoothly, so surly this improves the THD a little without so many voltage spikes, no?

No.

That is not harmonic distortion...it is just a crappy generator. THD is designed and built into, or out of, a conventional generator. They are usually fine on a construction site running a table saw. A modern home with modern electronics...not so much.

 

In a 4 decade career repairing generators, total harmonic distortion was never an issue. I'm sure on the engineering side, THD was considered, but I never went to a job and came away saying "THD is your problem, you must get a new generator. And we are talking about thousands of gensets, from 1 cylinder Briggs to 20 cylinder cats. In the nineties, ups systems were coming online and many of them had trouble accepting a generator, but it invariably was a frequency problem, too high, too low, too high of a slew rate,(slew rate is how quickly the frequency is moving). We worked with the ups guysto rectify the problem. Ups tech would widen the frequency window, gen tech would tighten up the frquency response. More modern ups systems seem to have a better frequency acceptance window than the old ones, also electronic governors and better regulators help a lot. This site primarily discusses small 3600 rpm gensets, there are zillions of them doing a lot of work, most of the problems in my experience has been improper governor adjustment, improper carb and fuel adjustment, dirty air filters, plugs etc. All this causes frequency and voltage problems. Inverter generators do away with many of these problems. My current genset is a Honda inverter type. My last genset was a 40 year old 2 cylinder Onan CCK, best small genset ever made, IMO. No avr, armature crank, 1800 rpm, cast iron crankcase, 380 lbs. I ran everything on that generator, tv,computers, furnaces, microwaves, never had a problem running ANYTHING.

 

Neither of the non inverter generators that my microwave and LED lights have issues with have governor or carburetor issues…..stable frequency and voltage. Measuring both with a Fluke 87. Similar values to what tabora sees with his generator. No surging or hunting. Minimal governor droop when picking up loads. One is a late ‘90s 3800 Watt Craftsman (Generac) and the other is a ’20 Honda EM5000 (since sold). Something in the microwave (magnetron?) goes into an audible resonance and my LED lights flicker at steady high frequency. The microwave resonance and LED flicker was notably less with the Honda, but it was still there. None of this occurs while on grid power or when powered by either of my two inverter generators.

 

You guys that have problems with non-inverter generators causing appliances to act goofy should try buying a large 2 or 3 inch ferrite coil and looping the power cord from your appliance through it about 4 or 5 times..

I built a track driven "pick and place" robot once in a 3 car garage.. The control systems all ran on 3 phase 480 so I had to build a rotary phase converter and then run it through a 240/480 transformer to boost the voltage.
One of the servo controllers had an attitude problem with that power setup.. I thought it was shielding so we replaced a bunch of control wires with shielded cable... didn't fix squat.. Then I ran the power input to the controllers through ferrite coils.. Each leg got 3 loops through its own coil.. problem fixed.

 

You guys that have problems with non-inverter generators causing appliances to act goofy should try buying a large 2 or 3 inch ferrite coil and looping the power cord from your appliance through it about 4 or 5 times..

I built a track driven "pick and place" robot once in a 3 car garage.. The control systems all ran on 3 phase 480 so I had to build a rotary phase converter and then run it through a 240/480 transformer to boost the voltage.
One of the servo controllers had an attitude problem with that power setup.. I thought it was shielding so we replaced a bunch of control wires with shielded cable... didn't fix squat.. Then I ran the power input to the controllers through ferrite coils.. Each leg got 3 loops through its own coil.. problem fixed.

What you describe is an RFI/EMI filter. The ferrite presents resistance to higher frequency content and converts that energy to heat dissipating it away leaving the lower fundamental frequency 50/60hz

This does not filter out harmonic distortion. To do that you need a load/line reactor. It's basically a large inductor and capacitor combo, but they are very large in size and not practical in the portable generator realm.

How Inverter generators work: They take a spinning permanent magnet rotor driven by the prime mover to excite a 3 phase AC alternator. All these phases are rectified which is then fed to the input stage of the inverter. It's higher than the final voltage (~200-300VDC for 120VAC output) to allow for proper regulation. That rectified charge is dumped into large input capacitors, to which the output stage will use PWM using fast switching IGBTs to approximate a sine wave output at the 60hz/120VAC. There are filtering components to remove enough of the hash, AKA transistor noise from switching on off so quickly in the 20k-100khz range...depending on how advanced the output stage is. The more one/off pulses to approximate the sine wave, the higher the switching frequency and efficiency. Resulting in very little THD, though switching noise is suppressed on the output, many cheap inverters skimp here just to pass FCC15 rules.


The 12VDC to 120VAC inverters add one extra stage, a boost stage. Multiple transformers inside connect their primaries in parallel, and the secondaries in series. Multiple banks of MOSFETs fire each side of the center tapped primary to ground creating an AC Square wave. The secondary windings in series boost the 12V to over 200VAC. Noone needs a ~50khz AC square wave so they rectify it to DC and dump into large input caps. The rest of the inverter stages are the same as described above.

I wrote this portion on my YouTube community page. It not only applies to HVAC but on any switch mode power supply device. Should hopefully be helpful info.
---

HVAC Problems on Portable Generators - THD (Total Harmonic Distortion) - Proper Grounding of HVAC Systems On Generator Power.

You find a lot of posts about these two topics. Why doesn't my furnace run on my portable generator? The biggest issue is not always THD, rather improper grounding when using a portable generator. However all these factors play into the main problem of the furnace not working on generator power.


- The #1 issue is surge protection. Most but not all HVAC control boards were NOT designed to have any type of surge protection. You will not find basic components like MOVs that are meant to short any voltage spikes to ground. Here in the USA the National Electric Code standards to voltage/frequency/THD denotes there is no need to add these components because it is "stable enough" by spec. Obviously not the case everywhere but trying to think of logical reasons why. There are aftermarket solutions to protect the 24VAC lines running the controller boards for example, and there are also whole house surge protection devices available.

24VAC Surge Protector: https://www.supplyhouse.com/Zebra-I...t-Surge-Protector-Plug-In-Surge-and-Spike-Protector-for-24V-Transformer-Systems

Whole House Surge Protector: GE Whole Home Surge Protection Unit-Panel Mount THQLSURGE - The Home Depot

Portable Generators, either brushed/brushless, are NOT going to have as stable of a voltage/frequency like the utility. A heavy load starts on generator power, the voltage drops as a result, and so does the frequency as the engine slows down momentarily until its engine governor can respond to the load. This momentary drop then quick rebound of voltage/frequency will often overshoot (AKA spike beyond the nominal voltage/frequency for a brief instance) to compensate for that instantaneous load draw. The spinning rotor of a generator is an electro magnet, or known as an "inductor." Inductors by design store energy, and as long as the voltage/frequency is constant, everything is good. When those change, the inductor resists that change, and that causes a voltage spike. It is at these moments where sensitive devices not properly protected for surge can fail.

- The #2 issue not often talked about is proper grounding and polarity of the generator wiring. I've read and seen too often the failure of an HVAC system is due to faulty grounding/wiring. Modern furnaces use a method called "flame rectification." A flame can actually be used as a rectifier (converts AC to DC) to sense if the burner is ignited or not. The neutral/earth ground in your main panel is the 0VAC reference point the HVAC controller needs to see for this process to work correctly. If your ground connections at your generator are not properly configured based on how you hook it up to your panel, whether it be an interlock, 2 pole transfer switch, or 3 pole T-switch, this can cause problems.

A. Two pole interlock breaker or Two Pole Transfer Switch to an L14-30 Inlet box at a main panel with its Neutral/Earth Ground bonded needs to have a "floating neutral generator." One N/G bond in the system that is utilized by the generator, called a "Non Separately Derived System." A Ground Rod at the generator is not required unless certain criteria in the NEC 250.52 (A) are not met.

**These are the most common LEGAL methods of connecting a portable generator to a house.

250.52 Electrodes Permitted for Grounding.

According to 250.53(A)(3), if multiple rod, pipe, or plate electrodes are installed to meet the requirements of 250.53(A)(2), they must be at least 6 feet apart.

www.electricallicenserenewal.com

B. The 3 Pole Transfer switch will change over the two hot X&Y leads AND the neutral wires. The Earth grounding lead is left solid connected between the generator and panel. This is known as a "Separately Derived System." In this configuration, a "bonded neutral generator" with its own ground rod MUST be used. This is because the transfer switch breaks the neutral ground bond at your main panel and thus needs to have it bonded at the generator. This maintains a single bond within whichever system is powering the house circuits.

***This is the least common configuration used in the USA.

Please refer to a licensed electrician that knows what they are doing and understands the NEC. I learn from research and listen to others more qualified than me!!!!!



- The #3 issue is High THD: What is THD in its simplest explanation without getting too technical? Its voltage/current at another frequency than at the 50/60hz commonly found in households. If I have 120/240VAC at 60hz, but I also have say 12VAC at 120hz, or 8VAC at 240hz etc, now my 120/240VAC is contaminated with voltages/currents that my devices are unable to utilize. This is commonly known as "DIRTY POWER." Most residential HVAC controllers run off of stepped down mains voltage. This would be 120VAC down to 24VAC. If the THD is high on the mains, the stepped down 24VAC voltage IS JUST AS DISTORTED.

**The effects of High THD:

1. Can cause the microcontrollers to lock up. Microcontrollers usually run on 5VDC, and stray voltage spikes at the higher harmonics will bleed through the rectification process and stop the processor from operating, malfunction which cascades to its external peripherals, or simply fail completely.

2. Excessive heat buildup can occur in the PCB components. This is because that voltage at the higher harmonics cannot be utilized by the devices, and that energy is wasted in the form of heat, shortening the life of the component. This is also true of the electric motors in your HVAC system.

i. A permanent split capacitor (PSC Motor) is an inductive motor, operates at a single speed. Due to their energy inefficiency (~45%) These are commonly found in older systems. High THD will create a "reverse torque" in the motor windings, opposite of the spinning direction. This leads to overheating of the motor and premature failure.

ii. An Electronically Commutated (ECM Motor) is a variable speed motor commonly found in newer HVAC Systems. Like the PSC, the same problems occur. High THD can also interrupt the PWM signals the controller board running the variable speed causing malfunction/failure. Voltage surge/spikes is the most common failure as it will destroy the MOV(s) located on the speed controller of the motor itself.


Hopefully this post will educate you on some of the issues to watch out for. The reality with modern HVAC systems is that conventional portable generators are simply not adequate to handle their power needs. However, there are measures you can do such as employing a proper certified electrician to install your generator hookup, add the proper surge protection to your house and its devices, and consider purchasing a proper sized inverter generator. They are the best generators IMO for home backup power as they pose far less issues than what is discussed here.

 

My question is how much of a difference, only electrically, does inverter tech make in real world emergency use?

Getting to the point and simply put, if I can offer my 2 cents:

Inverter - best at lower power, intermittent use if you need critical devices only and can load manage
Traditional (rotary) - best at higher power, base load use if you need "utility power"

For me in a whole house back up situation the difference would be if we need central AC or not. If not then we have enough inverter (5500w peak watts) power for "whole house" back up - including central heat (gas).

For small loads - camping to basic power backup at home - we have a 2200w inverter. But the primary is a 5500w inverter.

As to sensitive electronics - a quality alternator, for a rotary, is what you want. Mecc Alte is one brand. We have a 15kw gen with a Mecc Alte alternator that is under 4% THD. I would have no qualms about running "electronics" off of it, if needed. We have never needed it, to date, though.

Hope this helps.

 

My question is how much of a difference, only electrically, does inverter tech make in real world emergency use?

I'm no professor but in my house, there is no difference electrically. Zero. Nada. All of the modern household appliances and devices that I've run with my 2 different conventional gens work/perform exactly the same as they do on utility power. I get those same results with inverter gen technology.
Appliance wise that includes a propane furnace (2016), desktop PC, TV, entertainment center, fridge/freezer (Whirlpool), stand alone freezer, microwave, 120v well pump as well as no LED light issues either.

Just like the untold thousands and thousands of conventional generator users that report no THD issues, I can only surmise I am one of those fortunate souls. High THD? My junk just doesnt care. Power goes out, all they want is a source to bring them back to life.
In my small locale (now I dont know everyone), but I am estimating 90%+ are using the typical conventional gen with a few being 20+ years old. Are they having issues? Cant say for sure but I've yet to hear any.

I have to think 'if' the mass of conventional gen owners/users were having THD issues, we'd be seeing a new post (or more) daily stating their gen's THD issues.
I also have to wonder, 'if' these gens were giving so much trouble, why are they still on the market?

This sensitivity issue some are having has me curious. What exactly (in layman's terms) makes these appliances/devices so prone to to failing/inoperable with a higher THD gen? Is it the manufacturers use of poor/inferior materials within the appliance/device itself? Build quality? Overseas technology not up to spec or device demand?
Like said, I'm no professor so I dunno and can only speculate...

I often see high THD numbers of 20-25% shown/posted out here. Now along with that, what I rarely see mentioned is those high numbers are only measured when said gen is put to full load. To my understanding, the lower the load on the gen, the lower the THD, yes or no? Those numbers (if known) should also be displayed.

Like said, my junk doesnt give a hoot where the power comes from, just bring it. There are two specific reasons why I've switched over to inverter gens, (and THD has absolutely nothing to with it).
I simply want the much, much quieter/lower dBA level and the outstanding fuel mileage that the inverter(s) bring to the table.
Just to add, IMO having the ability to do a simple parallel with the inverter units I have is a bonus beyond compare.

Yes, the inverter gen indeed comes at a larger cost, but its worth it in the long run for me. Shop around, there are deals to be had.

 

BTW...Welcome to the forum Latent_Image! Excellent first post

Disclaimer- I am not totally new here, needed a new account since I couldn't a verification email to old account

Had to come back and edit, I had missed/overlooked the new account info. Still a great discussion post, welcome back!

 

BTW...Welcome to the forum Latent_Image! Excellent first post


Had to come back and edit, I had missed/overlooked the new account info. Still a great discussion post, welcome back!

Thank you. It's quite an interesting thread. I have learned a lot and have more questions as a result of the great thought provoking discussions.

 

The thing that made me retire my old Champion conventional generator and buy an inverter was the purchase of a new furnace. A quick Google search will revel that this is a common situation with modern high efficiency furnaces. See this post...and yes, they can go boom and cost more than a new inverter generator to fix them.

Other modern electronics such as refrigerators, microwaves, etc. will also either fail to operate or suffer damage. It seems as if the older electronics (aside from a few exceptions like the UPSs mentioned) didn't care about THD as much as the modern electronics. One reason for this is the change from passive filtering to active filtering, but there may be other differences as we are not privy to what goes into the innards of the things we buy. As the market becomes more competitive, manufacturers look for cheaper ways to design and build their products. Unfortunately, the result is an issue with non-grid power being applied. It is up to the consumer to figure that out. Grid power is typically 3% or less THD. A gen with 5% or less THD is highly recommended for home use. Generac has come out with a standby gen with less than 2% THD.

There are alternators such as mentioned above that are carefully designed and manufactured to produce less than 5% THD. Some of the larger conventional portable gensets have less than 5% THD. I don't know of any small portable gensets that have low THD in the conventional series...only inverters.

Here is an answer I received from MPP Solar regarding the use of my old Champion generator with their inverter in Line Mode. Notice that they reject dirty power rather than the device being destroyed by it. And it is not a "marketing ploy" for them to answer my question this way since they don't sell generators.

 

The thing that made me retire my old Champion conventional generator and buy an inverter was the purchase of a new furnace. A quick Google search will revel that this is a common situation with modern high efficiency furnaces. See this post...and yes, they can go boom and cost more than a new inverter generator to fix them.

Ditto that experience GenKnot! My high efficiency furnace is my most expensive electrical appliance by far. If I understand the manual and the error codes listed on the cabinet door, the furnace does some evaluation of the power quality and shuts itself down if the power is sub par. That's great if it prevents damage, but having no heat can also cause expensive damage to the house, so I decided to get an inverter just to be sure. If it ever shuts down on grid power and has a power quality related error code, I intend to hook up the gen.

My furnace did fail once; not because of generator power (it hasn't been used yet with a gen), but for some unspecified reason. It was expensive to fix, even with partial warranty coverage. The variable speed fan and controller had to be replaced. Now I am less enthusiastic about high efficiency furnaces. They use less fuel and are quieter than old school furnaces, but I hope I don't repeat that repair every 4-5 years. And that brings me full circle. Thank goodness my inverter gen hasn't failed; unlike the conventional gens, I wouldn't know where to start to fix it.

 

Here is an example of a conventional generator that has less than 5% THD.

WGen20000 Generator

For your toughest power needs, the Westinghouse WGen20000 Portable Generator is an ultra-duty generator engineered for strength. With 28,000 peak-Watts and 20,000 running-Watts, the WGen20000 is built with a brawny 999 cc V-Twin OHV Westinghouse Engine that yields up to 11-hours of run time on a...

westinghouseoutdoorpower.com

 

That's a beast. Thanks for the food for thought

 

My 2 cents:
I haven't had an issue with THD.
Fuel consumption is important.

I have had a Honda EU300is since 2008. It sips fuel and is quiet. It was originally purchased and used to power the horse trailer with living quarters (includes 13,500 Btu a/c and microwave). It has also powered the house when power outages occurred.
During hurricanes with outages lasting several days, I saw friends/co-workers run generators that used ~1 gallon per hour.
The Honda EU3000is average usage is 0.21 gallons per hour, normal range has been 0.17 to 0.28 depending on load. This is 0.81 gph less than the non inverters. Which saved about 19 gallons per day. multiply that by your cost of fuel...
The Honda has 1000 - 2000 hours on it. At $3. per gallon, that has saved $3600. in fuel. It cost ~$2000, so It has paid for itself, and is getting close to paying for itself 2x over.

Its shortfall is that is only produces 125 volts, so won't power my well pump. But will run the other necessaries. I looked into getting a larger Honda EU6500is, but ended up getting a military surplus generator. MEP-002A. 2 cylinder Onan diesel. No inverter. Loud. But only 1800RPM. Fuel efficient (0.4 - 0.5 gallon per hour). Can run the whole house including the well pump. Can run the clothes dryer or range burners as long as well pump doesn't kick on). Gen set is also mounted on a military trailer and for years it has been transported back and forth to my folks house to supply their power when out.

None of our appliances have had issue with either generator. The diesel is from about 1993? I think. It's pretty old. Maybe 1983? not sure. has ~2300 hours on the meter.
But I don't want to be pumping $100. a day of fuel into a generator. And fuel can be harder to get during an outage.
My folks recently got a EU7000is. fuel consumption is ~ 0.3 gph, quiet, inverter, runs all their needs.

I think the Inverters will save more money in fuel usage in the long run and pay for themselves. My repairs have been maintenance/fuel/oil/air filter/carb/engine related, not power related.
If the generator won't be used much (5 hours per year) it probably won't be maintained either. and probably won't start or run well when you need it. Those types of users are candidates for natural gas/LP conversion.

I had been wondering if a laptop or phone or whatever would even care? they get power from a DC converter. Maybe it is still 'dirty'?

I haven't seen the non-inverter generator give any appliance an issue.

 

Really don't expect to run a generator enough for fuel efficiency to be a driver but who knows. Get into a week or more of power outage and fuel availability gets more important.
Lived in this home for 30 years and the longest outage was three days, this year followed by 12 hours out a week or two later for different reasons. I expect the problem to get worse over time

I had some links to lower THD traditional gensets I am looking at now

 

@Latent_Image I guess to make it more in line with what you are looking for (according your opening post), I should list this one. It also has less than 5% THD.

WGen11500TFc - Tri-Fuel with CO Sensor

The Westinghouse WGen11500TFc Tri-Fuel Portable Generator with CO Sensor produces up to 14,500 peak watts and 11,500 running watts. The WGen11500TFc runs on gasoline, propane (LPG), or natural gas. The heavy duty 550cc 4-Stroke OHV Westinghouse Engine has a durable cast iron sleeve and runs for...

westinghouseoutdoorpower.com

 

I think the reason that THD, under and over voltage, and frequency excursions aren't 'things' for the vast majority of generator owners is because there's no obvious correlation between dirty power and any effects that might be having on the electric loads being powered. Generator use is typically episodic and infrequent. And anything electric is going to fail at some point. Few people are going to make the connection between a long-down-the-road failure and any acceleration in that device's failure because of the dirty power it was occasionally subjected to.

It's not unlike static discharge in a microprocessor environment. A poorly trained tech worker, failing to adhere to static prevention protocols, can easily wreak havoc on equipment in the lab or the factory. But the failures induced by his inattention will rarely exhibit themselves right then. It may be years before they do so. Doesn't mean the damage he caused is any less real.

Back in the mid-80's I worked for AT&T at an underground site about 25 miles west of Washington, D.C. The building had double nuclear-proof blast doors, the outer casing was sheathed in copper, and the whole buried, three-story complex rested upon huge springs. Intended to help provide federal government and DOD communications after a nuclear attack, the site had two monstrous jet turbine engines as a source of emergency power. Once a quarter those turbines were tested and the whole facility went on emergency power for an hour or so. I ran the computer floor and will never forget shaking my head at the ugly readings I'd see through my equipment meters. It all worked... the computers ran. But it was the ugliest power I have ever seen.

We had a dedicated tech team that repaired and replaced hardware when it failed. They visited all the time. I didn't think too much of it at the time... it was a large computer floor and there was a lot of equipment. When something failed you just kind of thought that must be luck of the draw. Statistical odds. But years later, in retrospect, with greater appreciation for power characteristics, I've often wondered how much of those computer equipment failures was related to, or sped up by, the dirty power that equipment was subjected to four times a year.

Even today, the vast majority of loads one might plug into a generator - any kind of generator - are going to work. Doesn't mean that some of those loads aren't being affected by things happening at a silicon level that we can't see.

 

BTW my dad worked in one those AT&T underground facilities with blast doors, dedicated air and lots of batteries in southern NJ area years ago. Got to visit a few times and was impressive.

So you are a fan of inverter power then I take it?

 

My 2 cents; High THD causes circuits to heat-up due to unwanted currents flowing thru them. Some devices can take the extra heat where-as others don't handle it so well.

I worked in semiconductor R&D for 20+ years, mainly in the Photo/Metro areas which are responsible for "printing" and measuring the line widths/spaces or "Critical Dimensions" (CDs). The smaller the CDs, the more compact and efficient they operate. Also with smaller CDs, more stuff can be incorporated into a single chip making the overall circuit design much simpler from a layout prospective.

Modern IC's use much smaller CDs than say 20 years ago. When the lines get smaller (within the ICs), they can't handle as much extra heat and may be damaged. When I started working in that industry in the mid 90's, the smallest CDs were ~1/4um. When I left that industry abt 6 years ago, we were printing CD's in the single-digit nanometer territory. Most of the devices we made were for computers and the automotive industry but that same technology is used to manuf all types of electronic devices.

With all that said, I did successfully power my somewhat modern (2019) Trane propane central heater sys with computerized thermostat using my old (1999) Yamaha 6600 brush-less generator for abt 3 days (off & on) with no issues during the great Texas snow/ice/grid event of Feb 2021. It's been 3 years, almost to the day, and the fancy smancy Trane thermostats are still working fine. Did I wound them? No clue.

 

Very informative reply, thank you
You mention "High THD". Would you consider anything above utility power to be high? Trying to confirm that number to be 5%.
As I dig a little deeper I am finding a number of non-inverter generators under the 5%

 

Duplicate post.

 

My advice is to borrow or rent a generator of the type/model and make of what you think you'd like to buy and try it at home in a simulated power out situation. If it runs everything that you want or need then you're all set.

I did that with the Honda inverter I bought. My old Coleman open frame non inverter would not run my new refrigerator or my new propane furnace. The Honda inverter would.
It's definitely not a marketing gimmick.

 

My old Coleman open frame non inverter would not run my new refrigerator or my new propane furnace. The Honda inverter would.
It's definitely not a marketing gimmick.

Then something was out of adjustment with the Coleman.. (its usually frequency as the governor spring ages) Coleman generators are no different than the larger whole house Generac units that start automatically when the grid goes down. And to this day, I have never heard anyone say their whole house backup generator won't run some appliance in the house.

 

👆 I like that advice. You may not find the exact model that you're interested in, but at least try out a generator that is about the same wattage and type (inverter or conventional) that you are interested in.

 

I use a 6500 watt Honda inverter generator (trifuel converted) for my house and I can honestly tell you that the sound level, fuel economy, and reliability is worth the extra money. After 10 years, I cannot even remember what I payed for it. It's ridiculously quiet (something I wish my neighbor would consider regarding his screamer genset), and easy to deploy on propane. That large Westinghouse someone mentioned earlier in the thread uses 17 gal of gasoline every 11 hours! Do the math -- it's costly and you'll either need a large on site tank or be shuttling over $100 worth of fuel every day! I think the one you're looking at will probably be at least a half to one gallon/hr generator. It doesn't take long for that to eliminate the initial savings of getting a less expensive non-inverter type generator. I get a lot of power outages yearly -- usually multi day to a week in duration. I usually use less than $200 in propane a year with that Honda (I'm plumbed to a 500 gal tank). I barely have to load manage (only for the water heater) and it runs everything including two ductless systems, a 240V well, all of the household appliances, etc. Just don't run heavy hitters simulaneously. As for reliability, I've adjusted the valves once on the Honda and keep the oil changed religiously. It just works, is stupid quiet, and a fuel sipper. Anyway, best of luck with what you end up choosing.

 

That large Westinghouse someone mentioned earlier in the thread uses 17 gal of gasoline every 11 hours!

I was looking at that genny to power a deep well pump (needs 16.4kW to start). Don't need that much for my other stuff. If I was to purchase one, it would only be used when I needed to power the deep well pump, so maybe an hour every 24 hrs. Running that monster 24 hours/day or even 12 hrs/day would be a waste for sure.

 

^Good stuff. Thx!

In regards to cleaning-up power, you mentioned a load/line reactor. While definitely not practical for portable gensets, what abt the whole house standby systems where size/weight are not necessarily significant factors?

 

How many years have we used the traditional generator for? At the end of the day if they were bad for electronics, manufactures would stop making them because people would be suing their arse's ... Plus if traditional generators were damaging electronics, it would be all over the net.