[toyotatech]

Could someone imform me on how I may go about having my portable home generator measured to see how clean the power is that it outputs. I am concerned that it may damage my new furnace or other sensitive electronics.

 

[Teetorbilt]

A GOOD electrician should be able to do this for you, if you can't find one you will have to go to an electronics tech. Explain in detail what you want done in advance to weed them out.
In general, most gensets are to provide you with the basics during times of crisis, not provide Inet access.

 

[mdshunk]

Hmmm..... you'd need to hook up with an electrical contractor that has a power quality analyzer. The average electrical contractor does not own this equipment, but one that does mostly commercial work does. It's a high-dollar piece. This measures several things related to the power output, with the "purity" of the waveform being among them. You'll pay at least a few hundred bucks for such a test. Measuring the power quality while the genset is partially and fully loaded should be part of the testing procedure.

I think that it is important to realize that the typical generator sold for home backup power is not intended to provide the cleanest of power. That being said, I believe that it is safe to say that home genset power is at least as clean or possibly cleaner than your local utilities's power. Having done hundreds of power quality studies, utility power is no where as "clean" as people might want to believe that it is.

Now, on to your furnace... the boards in HVAC equipment are fairly bulletproof. They are engineered to such wide tolerances, that they will readily tolerate wide fluctuations in the voltage and frequency of the input power. They will all tolerate voltages and frequencies +- 10% with no trouble. But, if you're considering operating your computer or stereo equipment on a genset, forget it. This type of electronic equipment demands power that's dead nuts nominal most of the time. While I hold to my basic belief that most gensets are at least as clean as utility power, I wouldn't bet the farm on it. As far as generators go, I've only personally done power quality studies on a few larger 6 and 8 cyl gensets. I'm not sure what you might be getting out of the more common Tescumseh/Briggs/Honda type generators. Most of the "whole house" type large gensets will have meters that show the voltage and frequency on each phase. While this may not show how "choppy" the waveform is, it can be a pretty good indicator of decent power.

 

[Teetorbilt]

md, you know what is coming out of a small genset, you know the voltage drops when certain items kick in and the spikes when they kick out. It's not the time to run electronic equipment. Most of them are crude.
Last year we lost the dishwasher, reefer (twice), a computer and some knicknacks due to both and without a genset interfering. This was just the power co. We also have whole house surge protection plus protectors for the computers and home theater.

 

[mdshunk]

What I'm saying is that the furnace will be fine on the generator. The computer and such will not.

Teetor's problem was obviously due to some other highly abnormal utility issue, not related to running items on a genset. If I had to guess, without knowing any particulars, I'd guess a loose service neutral tap. A surge supressor will do nothing to protect your equipment in the face of a loose service neutral. This can cause the nominal phase voltage to intermittantly rise well above the normal voltage and damage equipment, but not be identified as a genuine spike or surge by a transient voltage surge supressor.

 

[Teetorbilt]

md, we only had power for 3 days during Sept. The surges could have come from trees taking out power lines, exploding transformers or service crews from as far away as Canada trying to cobble the grid back together again.

 

[mdshunk]

.... trying to cobble the grid back together again.

There's a lot of wisdom in that statement. I was a tramp lineman for 3 painful years before I got married. During major storm repair work, you did some crap that you'd never in a million years do if you had a little time to do it right. We even used native trees that were nearby as push guys to prop up a pole that was leaning badly just to get power restored. Some of the piss-poorest work is done during storm damage restoration.