# Cleaner power with large generators



## jeb (Feb 16, 2021)

Hi Folks,

New to the forum here. 

I have a Generac UltraSource 15000 that I've had for about 10 years. I converted it to dual-fuel (gasoline and natural gas) with a kit from US Carburetion. Pretty easy conversion which includes the two regulators and various parts to complete the conversion. 
Overall this generator works fairly well to deliver lots of power, but it is definitely *not* clean power. I have some UPSs in the house that protect my computer equipment and it will kick in randomly based on different loads that are on -- mostly because of slight frequency drift (i'm assuming that is what is trigger the UPS to kick in). Those devices are fine as the UPS deals with this. But I have a few devices that have switching power supplies that do not like this (some Raspberry PIs) and it actually makes them reboot.

I've noticed that motors (like fans) are a little noiser when powered by this generator - I assume that is from the THD being higher on this model.

Here is a sample of the sine wave from my oscilloscope. You'll see the frequency is close (59.5Hz) But the sine was is skewed. 









When the washing machine is running..the switching of the motor triggers the UPSs to kick in..,the transient is so quick, I can't really capture it clearly on the Oscilloscope...all I see is the wave phase shift quickly.
I think long term I'm going to move to another model that has a cleaner sine wave. I originally targeted the 15KW generator to give me a little extra power given the theoretical drop when using Natural Gas in place of gasoline. My target was 12KW so I could run AC and occasionally I've had to use it for running my Arc Welder (thus the need for a portable or semi-portable generator).

So this takes me to my questions:
1. Is there any way to clean up the power coming out of this generator to make it more tolerable? (I think the answer to this is no, but thought I'd ask anyway  )
2. Which model of portable generator would you recommend which there are conversion kits for Natural Gas available? I want something in the 12,000w range as stated above. Targeting THD< 5%.
3. Ideally lower noise levels if possible ~75dBA would be ok.

I see the Westinghouse WGEN 12000 and the WPRO 12000 that seem to be lower noise (74dBA) and provide THD < 5%...but I have not see any conversion kits out there.
The other one that looks promising is the CAT RP12000E which is 12KW...but I don't see a noise figure for it nor have I seen any conversion kits.

Any recommendation of something in those categories that you'd recommend?

Thanks,

-J


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## jeb (Feb 16, 2021)

Also, is there an easy way to convert the dual fuel Westinghouse Gensets to Natural Gas? WGen12000DF Generator - Dual Fuel

I see there appears to be no factory available kit...but after-market is what I'm wondering about.

Since there is already a regulator there for propane...is it as easy as swapping that out with a regulator / load block and shutoff solenoid for natural gas? Or is there more to it? I don't have one of those in front of me to see if the fuel hose(aka vapor hose) from the regulator goes into the intake manifold - so should be universal or if it goes into the carb.

Thanks.

-J


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## Browse Deweb (Jan 16, 2021)

I would parallel two Honda EU7000is using their parallel kit. The inverter generators provide very clean and quiet power and can run up to 18 hours on a tank of gas. I know there are Tri fuel conversion kits available for the Honda, but not sure how well they work. This solution would not be cheap.


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## Old man here (Nov 5, 2020)

jeb said:


> Hi Folks,
> 
> New to the forum here.
> 
> ...


I have a 2016 version of the same generator, Generac GPE15000E. I see a similar sinewave on my scope connected to a 120V ac to 12V ac transformer. Are you doing the same? I get a small amount of distortion on grid power as well using the transformer.
I am not aware of any way to clean up this power cheaply. There are ways to do it, but they are way out of the average home owners price range.


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## jeb (Feb 16, 2021)

Old man here said:


> I have a 2016 version of the same generator, Generac GPE15000E. I see a similar sinewave on my scope connected to a 120V ac to 12V ac transformer. Are you doing the same? I get a small amount of distortion on grid power as well using the transformer.
> I am not aware of any way to clean up this power cheaply. There are ways to do it, but they are way out of the average home owners price range.


I actually had an old test dongle for sampling X10 home automation power line signals that I think just had a simple voltage divider in it. I used it because I had it lying around...but using a transformer like you did would probably be better as it would provide some isolation between the utility power and the scope. 

At any rate, ya, that is a pretty dirty signal. 

Browse Deweb, thanks for the suggestion on the two Hondas paralleled together. I'd prefer to go to a single generator if possible. But that two smaller ones are an option.


*Does anyone have a sample of the output of any of the THD < 5% generators? *I'd like to see what they are _*really*_ producing.


-J


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## Browse Deweb (Jan 16, 2021)

Here are some examples:








Generator Oscilloscope Waveform Measurements


How dirty is your generators electricity? Most people haven’t a clue. Others see their voltage and frequency to be on point and assume their generator is great. The truth is not all generators produce clean power, and the ones that advertise super low THD might not be up to snuff. I have scope...




www.powerequipmentforum.com





The thing I like about the parallel option is that if you don't require so much power during an outage, you can just run one and save on fuel. Also, if one generator experiences issues and requires maintenance, you still have one available to get through the outage.


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## jeb (Feb 16, 2021)

Browse Deweb said:


> Here are some examples:
> 
> 
> 
> ...


That is very wise. The List price on those are $5K 😧 so two really jacks up the solution price though....

thanks for the link on the waveforms...great reference.


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## jeb (Feb 16, 2021)

One of the things I notice is that when I have loads that are oscillating (in current draw) it seems like the waveform phase shifts a little bit. Its enough of a change where the UPS on my computer will kick in. Such loads like the clothes washer (front load) as it rotates back and forth...there is a significant spike in power draw as the motor starts (front load washer goes back and forth reversing direction during wash cycle). Also in the kitchen the Microwave as it cycles power output during certain cook functions...or believe it or not an electric toaster oven in the kitchen (I thought this would be purely a resistive load, but to maintain the heat setting, the model we have appears to pulse the power to the heating elements to maintain the temperature).

How well does the Honda EU7000is react to this kind of oscillating load changes? Are there any spikes, phase shifts or drifting in frequency until it stabilizes? Or does it react quick enough that you can't visually see the change on your oscilloscope output?

I didn't see any of the non-inverter generators that advertise low THD in that thread you referenced other than the Kohler 20Kw. Anyone have the output of a CAT RP12000E or one of the Westinghouse WGEN12000 or WPRO 12000? 

Generac XG10000E is claiming < 5% THD but I'd like to see what the wave form really looks like on these...


-J


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## Old man here (Nov 5, 2020)

jeb said:


> One of the things I notice is that when I have loads that are oscillating (in current draw) it seems like the waveform phase shifts a little bit. Its enough of a change where the UPS on my computer will kick in. Such loads like the clothes washer (front load) as it rotates back and forth...there is a significant spike in power draw as the motor starts (front load washer goes back and forth reversing direction during wash cycle). Also in the kitchen the Microwave as it cycles power output during certain cook functions...or believe it or not an electric toaster oven in the kitchen (I thought this would be purely a resistive load, but to maintain the heat setting, the model we have appears to pulse the power to the heating elements to maintain the temperature).
> 
> How well does the Honda EU7000is react to this kind of oscillating load changes? Are there any spikes, phase shifts or drifting in frequency until it stabilizes? Or does it react quick enough that you can't visually see the change on your oscilloscope output?
> 
> ...


How does the scope signal look while the washing machine is operating on utility power? Same test with the other appliances?


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## jeb (Feb 16, 2021)

I see the phase shift by a few degrees during the initial load. It happens so fast, that I can't capture it. Since its a digital scope, I'll see if there is a way to freeze and measure the shift.


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## Old man here (Nov 5, 2020)

jeb said:


> I actually had an old test dongle for sampling X10 home automation power line signals that I think just had a simple voltage divider in it. I used it because I had it lying around...but using a transformer like you did would probably be better as it would provide some isolation between the utility power and the scope.
> 
> At any rate, ya, that is a pretty dirty signal.
> 
> ...


I picked my transformer up at Home depot for low voltage outdoor lighting. It does need a load on it before it will put out voltage. An automotive tail light socket and bulb wired to the terminals is all it takes.


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## jeb (Feb 16, 2021)

I have lots of transformers lying around...so I can quickly make something if needed. 
The biggest challenge using a lower cost scope is you can see the waveform (skew rate, etc) and measure frequency/period -- which is good...but if you wanted to measure harmonics, you'd need a scope that can provide FFT (Fast Fourier Transform)...which mine does not.

Would be really nice if each generator manufacturer had to send in measured output / harmonics, etc to a public resource to see how they _really_ performance; kind of like how any RF based equipment has a detailed report with the FCC.


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## Old man here (Nov 5, 2020)

jeb said:


> I have lots of transformers lying around...so I can quickly make something if needed.
> The biggest challenge using a lower cost scope is you can see the waveform (skew rate, etc) and measure frequency/period -- which is good...but if you wanted to measure harmonics, you'd need a scope that can provide FFT (Fast Fourier Transform)...which mine does not.
> 
> Would be really nice if each generator manufacturer had to send in measured output / harmonics, etc to a public resource to see how they _really_ performance; kind of like how any RF based equipment has a detailed report with the FCC.


I agree, it is amazing what an instrument costs just to measure THD. I've been shopping for a used one but they are still expensive!


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## jeb (Feb 16, 2021)

One of the most frustrating things is when I call in to Generac (and now I have a call into Westinghouse), they don't want to provide any data. Makes me think they are scared to provide quantified data. Asking for a sample of the waveform the line I got from support was: "If you are concerned about the output of your generator, you'll have to take it to an authorized service center". Lame...but that is what I was told by the Generac support rep


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## Old man here (Nov 5, 2020)

jeb said:


> One of the most frustrating things is when I call in to Generac (and now I have a call into Westinghouse), they don't want to provide any data. Makes me think they are scared to provide quantified data. Asking for a sample of the waveform the line I got from support was: "If you are concerned about the output of your generator, you'll have to take it to an authorized service center". Lame...but that is what I was told by the Generac support rep


Unfortunately Generac is not customer orientated.


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## Bulldogger (Feb 19, 2021)

jeb said:


> Hi Folks,
> 
> New to the forum here.
> 
> ...


 I contacted Generac and was told that series does not, as you tested, have low distortion. Generac claims there newer series 15KW is low distortion 5%


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## Old man here (Nov 5, 2020)

Bulldogger said:


> I contacted Generac and was told that series does not, as you tested, have low distortion. Generac claims there newer series 15KW is low distortion 5%


Did they specify portable or standby generators when they made that claim? They do have a line of smaller portables that are 5% but they are way more expensive than the portable "GP" series.


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## Bulldogger (Feb 19, 2021)

Old man here said:


> Did they specify portable or standby generators when they made that claim? They do have a line of smaller portables that are 5% but they are way more expensive than the portable "GP" series.


 I asked about the 15000 watt and the 17500 watt portable specifically. I was told that they are basically the same as what they use in the standby generators. I called and spoke with a customer service agent. She said the older Guardian portable 15KW had high distortion.


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## Old man here (Nov 5, 2020)

Bulldogger said:


> I asked about the 15000 watt and the 17500 watt portable specifically. I was told that they are basically the same as what they use in the standby generators. I called and spoke with a customer service agent. She said the older Guardian portable 15KW had high distortion.


I have a GP15000E from 2016 or 17. I cannot say what the THD is rated at but, if Generac is not advertising them as 5% THD, they are higher than that.
If you look at the current product marketing for these models, it still does not state any THD rating. I will guarantee you that if it was 5% it would be in their marketing materials.
You can go back in these posts and see my scope results for the sinewave put out under different loads. Nothing like an invertor generator but not to bad.

I'm not knocking Generac products, just stating the facts.
My generator has served me well through the power outages when needed. My house is all electric by the way.


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## Bulldogger (Feb 19, 2021)

Old man here said:


> I have a GP15000E from 2016 or 17. I cannot say what the THD is rated at but, if Generac is not advertising them as 5% THD, they are higher than that.
> If you look at the current product marketing for these models, it still does not state any THD rating. I will guarantee you that if it was 5% it would be in their marketing materials.
> You can go back in these posts and see my scope results for the sinewave put out under different loads. Nothing like an invertor generator but not to bad.
> 
> ...


 Don't know. I believe you are right that it would be in the marketing. Customer service agent got some tech guy. I went with 27KW Power Horse. Generac is so popular that the wait time is long.


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## Old man here (Nov 5, 2020)

Bulldogger said:


> Don't know. I believe you are right that it would be in the marketing. Customer service agent got some tech guy. I went with 27KW Power Horse. Generac is so popular that the wait time is long.


Wow, that's a big dog there. The only issues with these larger generators is that they only have a 50 AMP outlet to connect to your main service. Of course, they have more power for you to use, but that additional power will be in the form of extension cords.
I hope it serves you well. Keep us up with your experience with this new generator.


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## jeb (Feb 16, 2021)

I really wonder how they get these traditional generators to have cleaner power? I mean what *changes* did Generac and the rest of the gang of manufacturers do in order to lower the < 25% to <5% THD - since they are not a drastically different design such as the inverter styles?

How much of this is marketing? and does it maintain that THD all through the rated power? Or is it at some lower power load value? 

I wish they'd provide a sine wave shot and FFT output of their genset over the range of rated load...but I have yet see anyone do this except for Honda on their inverter styles generators. Very frustrating...

-J


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## Old man here (Nov 5, 2020)

jeb said:


> I really wonder how they get these traditional generators to have cleaner power? I mean what *changes* did Generac and the rest of the gang of manufacturers do in order to lower the < 25% to <5% THD - since they are not a drastically different design such as the inverter styles?
> 
> How much of this is marketing? and does it maintain that THD all through the rated power? Or is it at some lower power load value?
> 
> ...


Jeb,
I think the quality of the overall generator "head" determines the quality of the power produced in relation to THD. It boils down to design, and rotor and armature manufacturing specs.
Look into "skewed" rotors. I think that is part of the secret sauce as well. I have no ideal how much "skew" is required, but I do know it plays a role in cleaning up the output.


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## ajnuzzi (12 mo ago)

jeb said:


> Hi Folks,
> 
> New to the forum here.
> 
> ...


the Wgen12000df already comes mounted with two regualtors. All you have to do is bypass the top propane regulator. If you look up Wgen12000df natural gas conversion on youtube you'll see a video of it done and see what I mean, it's a piece of cake, don't even have to mess with the carb


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## Columbotrek (11 mo ago)

jeb said:


> Also, is there an easy way to convert the dual fuel Westinghouse Gensets to Natural Gas? WGen12000DF Generator - Dual Fuel
> 
> I see there appears to be no factory available kit...but after-market is what I'm wondering about.
> 
> ...


Looking at you tube videos, the conversion looks as easy as changing a metering orifice down stream of the regulator, (the same part used in the altitude kit) to a larger size so more gas flows. That is what the tri-fuel gens do when the fuel valve is changed from NG to LPG. Rolls in a larger hole. The kits have an adjustable valve so the user can dial in the amount of gas metered. Great for the competent. Bad for the others which must be why that method is not used as a stock setup. I watch the videos and they twist the nob until it runs smooth. But that can not be all there is to doing it correctly. Hopefully the stock regulator has sufficient flow capacity to meter an additional 15% ish additional NG than was needed for LPG. The end game trick is to get the A/F ratio correct so as not to cause harm to the engine.


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## speedy2019 (Jan 29, 2019)

Old man here said:


> I have a 2016 version of the same generator, Generac GPE15000E. I see a similar sinewave on my scope connected to a 120V ac to 12V ac transformer. Are you doing the same? I get a small amount of distortion on grid power as well using the transformer.
> I am not aware of any way to clean up this power cheaply. There are ways to do it, but they are way out of the average home owners price range.


The only thing is to make sure the engine is well maintained so it runs as smoth as possible, but that probably wont change much.


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## speedy2019 (Jan 29, 2019)

I guess if manufactures stated the THD on generators, no one would buy them as Im guessing most will be pretty shocking.


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## ajnuzzi (12 mo ago)

jeb said:


> Also, is there an easy way to convert the dual fuel Westinghouse Gensets to Natural Gas? WGen12000DF Generator - Dual Fuel
> 
> I see there appears to be no factory available kit...but after-market is what I'm wondering about.
> 
> ...


I just converted my wgen12000df to natural gas. You have to buy this fitting:








Everbilt 1/2 in. Barb x 3/8 in. MIP Brass Adapter Fitting 800199 - The Home Depot


These hose barbs are made of durable, corrosion resistant and lead-free brass while conforming to NSF 61 and 372 and are registered in Mass. They have several barbs to hold when inserted into tubing. Best for use with plastic, vinyl or rubber tubing. Pair with a hose clamp for a more secure fit.



www.homedepot.com





Also you'll need a 3/4" black iron 90 degree street elbow, a few 3/4 nippes, and 3/4 quick connects (optional)

All you do is bypass the top propane regulator completely, remove the small orificed 1/2 hose fitting that's on the top of the garrettson regulator and replace it with the one from home depot and then put your street elbow to the 3/4 inlet of the regulator. Some use a load block to adjust fuel instead of that 1/2 to 3/4 fitting I used. I originally tried the load block and even all the way out the generator wasn't getting enough fuel and was bogging down with a load. As soon as I swapped that with the straight fitting ran absolutely perfect. Feel free to message me if you have other questions, it really is that simple


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