Power Equipment Forum banner
1 - 13 of 13 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
Good Day all,
Looking for some input. I Currently I have a predator 8750 used as a portable generator tied into a transfew switch. I only power the kitchen (fridge), a few lights/outlets in master bedroom and bath, and our natural gas Navian Combi boiler for heat and hot water.
My question is should I need to invest in an inverter (such as the Wen 8750) to protect my Navian boiler? The more I read about generators the more I learn about THD. I am guessing my current gen has a high THD. I will add I have used my generator for 5 days with the Navian boiler and it ran no issues. Id hate to waste money on a new generator when the current one powers everything just fine.
I was also thinking of getting a tri fuel generator to tap into my NG line, but cannot find any trifuel inverters..
 

·
Registered
Joined
·
1,044 Posts
its an older non inverter type
Ah, the older model. Yeah, those are pretty dirty. As for the THD being an issue for your boiler, it may not be as you have already been running it. There is a lot of data about THD and electronics in general that you might want to consider though. For one thing, high THD can cause damage over long term use even though the item appears to not have an issue with it. If the item/appliance has unusual noise emanating from the electronics when running on a dirty gen vs grid power, then that can be a sign of potential damage being done.

In my case, I installed a new high efficiency furnace and was told by the installer not to run it on my existing gen because it was an old high THD conventional model. I ended up buying a WEN GN625i because of that. It has a very, very low THD of <1%. A gen having <3% is perfectly acceptable for most everything as far as I know.

I guess to answer your question about needing to buy a new low THD inverter gen is I don't know. You might want to contact Navian and see if they have any recommendations. However, buying a low THD gen will future-proof you for whatever you might buy next...maybe a new fridge. You never know what is coming onto the market that can have issues with high THD. Having a low THD gen cant be a bad thing! And, an inverter gen will usually save fuel vs a conventional unit.
 

·
Registered
Joined
·
34 Posts
FWIW: About 6 years ago I powered a fairly-aggressive 3-way sound system (plus on-stage band power / monitors) at a local outdoor concert on a non-inverter Predator 8750.
The event provided the gen, not I.
To be on the safer side I brought my analog mixer but my power amps were digital....
Not a hiccup over an 8 hour festival although the gen was rather loud...
 

·
Registered
Joined
·
136 Posts
FWIW: About 6 years ago I powered a fairly-aggressive 3-way sound system (plus on-stage band power / monitors) at a local outdoor concert on a non-inverter Predator 8750.
The event provided the gen, not I.
To be on the safer side I brought my analog mixer but my power amps were digital....
Not a hiccup over an 8 hour festival although the gen was rather loud...
I found frequency being high more of an issue than a distorted wave form. To high and smart dimmers strobe the attached LED bulbs they control. Same bulbs on smart switches do not strobe. Most things today use switching power supplies that can take input power between 50 and 60hz and voltages between 110 and 240. The first step performed is taking what ever comes in and converting it into DC then from that making the various DC voltages needed by the unique electronics within. What I can attest to is my several computers, HDTV, modems, routers, Raspberry PI, LED lights, HVAC, Microwave, smart switches et all all work fine with a 9500 Watt 240V split phase generator. Even the smart dimmers work correctly if I can keep the frequency <= 60Hz. Bathroom exhaust fan seems a bit louder on generator. I do not power the Laundry, Dishwasher, or Sink Disposal from the generator so I can not speak to those appliances. He may be fine with what he has already.
 

·
Registered
Joined
·
485 Posts
I found frequency being high more of an issue than a distorted wave form. To high and smart dimmers strobe the attached LED bulbs they control. Same bulbs on smart switches do not strobe. Most things today use switching power supplies that can take input power between 50 and 60hz and voltages between 110 and 240. The first step performed is taking what ever comes in and converting it into DC then from that making the various DC voltages needed by the unique electronics within. What I can attest to is my several computers, HDTV, modems, routers, Raspberry PI, LED lights, HVAC, Microwave, smart switches et all all work fine with a 9500 Watt 240V split phase generator. Even the smart dimmers work correctly if I can keep the frequency <= 60Hz. Bathroom exhaust fan seems a bit louder on generator. I do not power the Laundry, Dishwasher, or Sink Disposal from the generator so I can not speak to those appliances. He may be fine with what he has already.
I have a cheap 2600/2800watt non-inverter AVR generator and that does a pretty good job at keeping the hz at 50 give or take 2-5hz at either side. The only type of bulbs that my generator has problems with are halogen bulbs for some reason, as the generator causes them to slightly flicker very fast.
 

·
Registered
Joined
·
1,386 Posts
I only hear a slight pulsating whine from the bathroom exhaust fan when running on gen. I think it's more to do with the sound of the generator interfering with the sound of the fan (waveform interference). The gen is running at a slightly higher or lower RPM while the fan is tuned for exactly 60Hz and likely being forced to spin slightly faster/slower.

No flickering lights. Have about 6 UPSs with several computers and network equipment. Running them on gen, as Genknot mentioned, may have a long term effect on lifespan. Then again, if you're only running them from the gen a few hours to a few days a year, the odds of them failing are very low.

On the other hand, if you really want peace of mind, upgrading to an inverter gen should run your sensitive equipment indefinitely without any foreseeable issue. I am unfortunately in a corner of the world where they're still prohibitively expensive.... even the Chinese no-name brands costs over twice or three times their non-inverter counterparts with the same kW rating.
 

·
Registered
Joined
·
485 Posts
I have a 3d printer that I have connected to my UPS, as a print can take a few days to print and you cant resume printing if you have power loss. So I tested it out with a fake powerloss while I was printing...
,
Turned off the mains power to the UPS, so UPS used battery mode..... Printer didnt detect any loss in power and carries on printing
Connected the UPS to generator, so the UPS flicks from the battery mode to the generators power ....... And the print still carries on

I would of thought a 3d printer would be quite tricky to run from a generator, because you've got 3 motors stopping/starting, going back and forth, Plus 2 heaters constantly turning on/off. But my generator handled the printer fine with only the odd occasion where the UPS would take over and flick to battery mode for a second or two.
 

·
Registered
Joined
·
134 Posts
Two issues affecting power, as it runs around your house wiring, are THD and power surges (big and small).

You can produce clean (low) THD at the generator level, which is great going into your house wiring ... unfortunately, everything else in your house is throwing out THD, so the issue is still there. Most folks follow the marketing, and buy a low-THD generator. Tons of research out there indicating it may not be as important as ...

Power surges ... these come in big sizes (nearby lightning strike, the worst) & medium sizes (power grid events like nearby transformer blowing, other grid surges) to small size ("micro-surges" from household equipment). It is the latter that really impacts sensitive electronics, and HVAC can be amongst the most sensitive, depending on how the manufacturer protects the boards (or doesn't). You can find HVAC websites that discuss this issue.

So, you can spend more on THD generators (twice as much?), or not nearly as much on "surge protection", in the form of Type 2 SPD (surge protection device) at the circuit breaker panel level, and Type 3 SPD's (surge protecting power strips & such) at the important household devices (HVAC's, TV's, Computers, etc.) Most HVAC's have specialized Type 3 SPD's available, but these have to be researched & bought.

I've got a couple of other threads down below that go into more detail on SPD's & lightning protection. THD threads abound on this site ...

Hope this helps!
 
1 - 13 of 13 Posts
Top