I have a DeWalt DXGNR7000 generator with a bonded neutral. I’m okay with house wiring, the fine folks here on Stack helped me out with that.

However, I know that these types of gensets create 60hz sine wave power but I’m informed there is lot of noise and frequency variation... like a LOT. Like all over the place...

And I guess that’s okay for my LED light fixtures, and a microwave oven, and circular saws etc, but not so much for satellite receivers, TVs, computer etc.

So instead of buying a (much) more expensive and less powerful inverter genset, I thought about putting a consumer UPS backup, like APC with their AVR feature, in front of the sensitive stuff.

Good or bad idea?

Any guidance is, as always, very much appreciated!

  • that is a good idea – jsotola Mar 5 '18 at 1:42
  • Inverter based gen sets tend to be better regulated than standard alternator units from the units I have checked (with a oscope and power monitor equipment looking at harmonics. With that said I have our computers and satellite equipment on 1 ups, and a second powers our video survelance & recording equipment and tv. As far as the microwave it maybe should be on a ups but the microwave draws so much power a ups for just that would be needed and I haven't lost one yet while on the generator. So I figure if we do lose the microwave it will be time for a new one. – Ed Beal Mar 5 '18 at 3:32

A regular consumer UPS will keep the voltage within acceptable limits for electronic equipment, but it won't do much cleanup of electrical noise or irregular frequency while it's powering the equipment from the mains power. That's because they're designed to supply mains power as long as it is available. The battery kicks in only if the mains power goes out or drops below a minimum threshold. Surge protection protects against high voltage spikes.

An "online" UPS will do what you're asking. With these, you always operate off the battery, so the output is a constant voltage, constant frequency, and noise-free. The mains power keeps the battery charged when it's available. Voltage or frequency fluctuations, noise, or other problems don't affect their ability to charge the battery.

That's the basics. Unfortunately, things are a little more complicated as far as what you can actually buy for the kind of application you have. Many products are actually hybrids, particularly in the size used for home electronics. This discussion by APC describes the technologies available and what they can do as far as cleaning up messy power. You can use that to compare the products available (and their costs). Here is some summary information from that link:

enter image description here

enter image description here

As you can see, the technology that does what you want is generally expensive or impractical for applications smaller than commercial use. But at least you have the information to make a more informed decision.

  • I have several older APC ups units the only problem with these is they do kill the deep cycle batteries about every 3-4 years, maybe the new ones have better chargers that float better than trickle, but I know they have saved me $ in the long run not only from being on a generator several times a year but eliminating power spikes that we get from time to time. – Ed Beal Mar 5 '18 at 3:37

If you want a surge suppressor, you can buy units which are only surge suppressors, from top-tier electrical distribution equipment vendors like Eaton or GE. Since they only do the one thing, they are very good.

  • Computers are going to need the spaghetti dinner anyway, so might as well pig out. – JPhi1618 Mar 5 '18 at 14:50
  • @JPhi1618 the problem is if you're talking UPS, those don't come with breadsticks at all. UPSs do not provide surge suppression unless they graft it on for some reason, and then no one expects them to be good. The flaw in my answer, if anything, is implying they do. – Harper - Reinstate Monica Mar 5 '18 at 15:37

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.