A search of this forum using the word "Generac" will tell you more than you probably want to know. Your generator is very likely to be (A) overloaded or (B)set up improperly.

Scenario "B" is my guess. Having said that, Generac would not be my first choice of brands for a number of reasons. Most of them have been outlined in the threads you will find with a search as suggested.

I don't know much about generators but my feeling would be to get a new generator. Granted the 60Hz rating probably comes with a tolerance of +/- a few Hz, the computer power supplies should be able to handle 57Hz since most supplies are rated 50 to 60Hz. I'm wondering if there was some sort of a voltage spike that killed the computers. I looked at some the generator specs for Generac and there was no tolerance listed for the 60Hz frequency but it also mentioned solid state regulation with a 1% tolerance which should put you fairly dead on to 60Hz assuming that the solid state regulation is for both voltage and frequency...the literature was not clear.

As far as putting in UPS's for the computers as fix for the generator problem...well..if there is truely a problem with the generator then the UPS will just be a bandaid fix. Looking at the specs for APC UPS's, their input tolerance is 60HZ +/-3 and if you're getting 57Hz, I feel that the UPS would/could constantly be switching over to battery to maintain a 60HZ output and this will probably prematurely wear the battery out.

On another note, getting a UPS in general is probably a good thing to do. The UPS would have probably saved your computers. The UPS will help ride out any over/under voltages or any other abnormalities on the line.

I have one for my computers and I leave the computers running 24/7, even through thunderstorms when the electricity dips in and out. The only time I've turned the computers off was during power outages. I once got burned and lost a computer due to a voltage swing...I've been using UPS's ever since.

I hope this helps. Hopefully someone else in the forum has better generator experience...I'm speaking with the general knowledge of being an electrical engineer.

I'm surprised if 57 Hz caused computers to blow out. My old Dell computer is rated for 50/60 Hz and like most electronics probably would operate well above 60 as well.

Motors may have trouble starting or overheat under heavy loads on slow frequencies, particularly below 55 Hz. Big heavy transformers in electronic equipment might eventually overheat at 55 Hz and below.

I suspect voltage (continuous or surges), or operation at speeds well outside the 55-65 Hz range was responsible for the computer problems. That said, the Generac was undoubtedly intended to run at 60 Hz and its governor should be adjustable to that speed.

You need to make sure that the electrical loads are disconnected from the generator while it is coming up to speed and when it is shutting down. A proper automatic transfer switch should be set up to do that. If it is manual, your operating procedure needs to assure that the house is only connected when the generator is running at the proper speed.

Thanks for the input so far. I will, indeed, do a search here for the Generac name.

Regarding the UPSs, my husband has had a CyberPower 550VA on each of his computers for several months now, and they were in place during the testing.

We trusted the electricians to set up the automatic transfer switch properly and that the generator itself would work as intended.

I'd appreciate any other thoughts or suggestions.

Regarding the UPSs, my husband has had a CyberPower 550VA on each of his computers for several months now, and they were in place during the testing.

i suggest your husband look and see WHERE onthe UPS he was plugged in. most have protected slots and battery/protected slots. the protected only slots do not provide UPS protection, just surge. i made that same mistake once and a very quick power blip killed a PC of mine.

all sensitive electronics should be on a UPS to prevent jsut such a thing happening.

it also sounds like the guys doing the install know nothing about generators. i have yet to see one that you could not adjust the frequency on it, other than some real old piece of junk ones.

never hire an electrician to setup a generator. hire an electrician to wire it up, and hire a generator tech to do the actual setup/adjustments.

Hi,

I am actually quite surprised at the issues you are having with your generator. To me 57Hz to 60Hz is a small difference. To me it seems that you have something else amiss in your wiring of the generator.

Computer power supplies are mostly switch mode these days and will be able to adjust to the slightly different frequency.

The thing which makes me suspicious is your fan just buzzing. A fan is not like hi-tech, it is just a motor. Why would it start buzzing? It seems that you have something else out of wack here and not just a matter of frequency. If the frequncy was wrong, it would still spin be it slightly slower perhaps. Granted the current may be a little higher, but at 5% difference (57Hz to 60Hz) I think it should be fine.

Does your fridge run O.K. as does your lighting? Lighting (vanilla light bulbs anyway) should be the least sensitive to differences in power frequency and up to a point voltage.

I have a Cummins Onan generator and everything works just fine on it.

My hunch is as follows:

1) 57Hz to 60Hz is a minor issue
2) Something else which is a bigger issue is not right here
3) My guess would be the way the Generator is hooked up to the house, or you may have a generator which is not what you think it is. What is the model of that generator?
4) When the electricians took readings, did they check readings at the computer power outlet? I am trying to reconcile that they took readings, and confirmed that everything was O.K., when you are having these issues.
My hunch here is that they took readings at the generator, and those were correct. However they did not take readings at the power outlets to your computer etc. They did not do this because hooking up the house was causing all these issues and they did not want to damage anything. So they checked the readings at the generator only, without hooking it up to the house.
5) Worth getting I think a second opinion from another electrician who has experience in backup power systems. One often confused area is the switching of neutrals, and ground bonding. Backup power systems installs are sort of rare, so if this is your electrician's first time install, then he may have confused the generator hook up at the transfer switch and how the neutral should be handled and how the generator should or should not be bonded to ground. I have included a PDF link which explains the issue. It is sort of tehcnical, but it is important to get it right.

Hope this helps,

Warmest regards, Mike.

Here is a link that might be useful: AC Power Hookup

I'll send it on to my electrician and hope he reads it. The info is definitely beyond my ability to understand but he should be able to figure it out.

If its any help, I have a Generac 15kw natural gas model with the eletronic govenor and my computers, home automation, home theater etc have no difficulty. The only items I had the DID have a problem with the generator power was 2 Cyberpower UPSs. I replaced them with APC models specified for use on generator systems (not all are due to the varing frequency) and problems were solved. Generac was installed in 2005 and has run fine since. Only its annual maintainance. Has gotten us through several power outages, one lasting about 48 hours.