For the UPS curious:
What Is The Difference Between An Online And Offline / Standby UPS?

Gets interesting when we mix the above with the various wave shapes a UPS can provide. On another UPS related note when you are setup like I am the UPS sees very little use before the whole house generator is online, only about 10 seconds so my concern is only to prevent any of the home computers from crashing, keep the cable modem from a reboot, maintain the home security system and keep the cable TV set top box from doing a reboot which takes about 5 min on a good day. Early on my older APC 1.5 KW UPS units had fits running off the generator. They were so sensitive to voltage and frequency they would just cycle on and off. They now make newer units like I got for my wife which actually have a generator setting where they are less sensitive and transfer fine when the generator comes online. Just something else to consider if a UPS is used with a genset.

Ron

 

An alternative solution would be to have the generator keep the battery for the UPS charged while the generator was running. Battery charging is far less particular about noise. The hookup would be more complex because the UPS would not be on a generator supported circuit, and you would need to have some exterior generator supported battery charging arrangement, but it ought to solve the problem. It would be a more complex solution, but sometimes the simplest is not the best. And it will offer the benefit of being fully automatic, not requiring human intervention either for starting or stopping. And an unanticipated extra benefit is that as soon as things return to normal power, the UPS battery is already at full charge, or very close, ready for the next time.