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10/20/2017 1:01:18 AM
9/22/2017 12:11:25 AM
Posted: 9/25/2005 1:04:54 PM EDT
We are trying to run a 5000w generator during power outage (Hurricane Rita). This is a gasoline powered generator.

The problem is that the 120 volt outlets are putting out WAY too much voltage (150 volts at fast idle, wel lover 200 at full throttle). I'm assuming that there is some kind of faulty voltage regulator, but the schematic in the owner's manual doesn't show a voltage regulator. The manual does show a capacitor in the alternator, but I don't know what its function is.

Any generator experts here ??
Link Posted: 9/25/2005 1:07:11 PM EDT
Many generators have a 220/110V switch that you choose your output voltage with.

Could this be it?
Link Posted: 9/25/2005 1:15:14 PM EDT
You shouldn't be adjusting engine speed, it's a governed system. You need 60 hz and you'll only get it at one engine speed. Sounds like you've got a 220 genset running at an odd RPM.

99% of the time it should be running at 3600 rpm, unless it's a big set which are usually 1800.
Link Posted: 9/25/2005 1:15:27 PM EDT
I have limited generator experience. But...

Shouldn't the engine speed remain relatively constant? If the engine RPMs change, the frequency of the ac sine wave (60Hz) would also change.

My generator runs about 1/3 to 1/2 throttle without load. When loaded, the governor tries to maintain a constant engine RPM in order to keep the loaded frequency constant even though the armature load tries to slow down the engine.

It sounds like someone messed with your base throttle setting and the governor isn't working properly.
Link Posted: 9/25/2005 1:19:45 PM EDT

Originally Posted By K2QB3:
You shouldn't be adjusting engine speed, it's a governed system. You need 60 hz and you'll only get it at one engine speed. Sounds like you've got a 220 genset running at an odd RPM.

99% of the time it should be running at 3600 rpm, unless it's a big set which are usually 1800.

Sound like this is the problem. Then engine should remain at the same RPM reguardless of the load on it, unless it has some kind of wierd rectifier setup in it like a car's alternator, but I don't ever recall seeing anything like that. Doesn't mean such things don't exist though.

Can you provide the make and model of the generator? That might help some of the more knowledgable people here (myself excluded) in the diagnosis.
Link Posted: 9/25/2005 1:34:29 PM EDT
Generator is a Devilbis GB5000. Engine is Briggs & Stratton (not that this matters).

I have owned other (Honda) generators whose engine speed varied with the electrical load (every time we would plug in another appliance, it would speed up). But in all cases, the voltage never varied.

I was assuming this should be the case with the Devilbis.

Still needing help.hinking.gif
Link Posted: 9/25/2005 2:19:12 PM EDT
I've cross posted this in our ARFCOM surivival forum. Your thread is here Need Help With Home Generator Problem, as posted by dawg23 in GD forum

Come and visit us ARFCOM survival forum. We've got a generator FAQs tacked there.
Link Posted: 9/25/2005 2:29:17 PM EDT
Be sure it is grounded properly.

Brad
Link Posted: 9/25/2005 2:32:42 PM EDT
[Last Edit: 9/25/2005 2:41:55 PM EDT by Robert2011]

On your model RPM controls the voltage and frequency. The throttle or governor could be loose or the adjustment off. It's where I'd look first and probably the only thing you can adjust or fix yourself.

ETA: It should produce the correct voltage at 3600 RPM.

Some of the high end Honda's have built-in inverters so they run at different RPMs. The Devilbiss GB5000 should stay at 3600 RPM no matter what the load. The governor should keep it there. Also make sure it is set for 120v and not 240v.
Link Posted: 9/25/2005 2:48:33 PM EDT
Link Posted: 9/25/2005 3:05:24 PM EDT
You either have a faulty governor, or an internal problem in the genset. I'd suspect the governor, after testing the internal capacitor.

Engine speed remains cnstant, throttle setting will be automatically changed to maintian RPM.

If you don't know how to fix it, I'd take it to a generator shop.

Ops
Link Posted: 9/25/2005 3:46:35 PM EDT

Originally Posted By Robert2011:
Some of the high end Honda's have built-in inverters so they run at different RPMs.


Good call Robert 2011, I've seen one or two of those Hondas in the past, but I think you might goofed on your terminology. I think I goofed too when I said some have wierd rectifier set ups. I guess it would have to have both a rectifier and an inverter if the alternator were turning at a rate other than that needed to produce 60 Hertz.
For the record, alternators produce alternating current.
an inverter turns DC to AC
a rectifier turns AC to DC.
Link Posted: 9/25/2005 3:51:08 PM EDT
You should have paid extra and got a Honda with an inverter. The power output is extremely clean sine wave. Clean enough to run electronics and sensitive stuff on it. We had a cheap one and it would surge and cause all sorts of problems.
Link Posted: 9/25/2005 6:53:56 PM EDT

Are you keeping the 120 and 240 separate?

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