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Generator voltage jumps to 400!


twisted99's Avatar
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08-14-07, 05:13 AM   #1  
Generator voltage jumps to 400!

Friend has a B & S 5500 watt generator that he got used, we freed up the governor which was stuck. Tested the voltage 220-245 range, except if you rev the engine it would jump to 400. Did the same test on my new Honda, and the voltage remained stable. Where do I go from here? Thanks

 
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cheese's Avatar
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08-14-07, 10:09 PM   #2  
I'm not an expert on the power generating end of a generator. Someone here should have some advice for you. I assume this must have a regulator, which may be at fault.


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08-15-07, 03:58 AM   #3  
The voltage increase would be expected when you "revved it".

A generator is meant to operate at a constant rpm.
The mechanical governor is meant to increase power to the engine when a load is applied but only to the preset rpm.

To test the generator output voltage you would not touch any engine controls.
Start the generator and plug a load in to see if the voltage changes.


GregH.........HVAC/R Tech

 
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08-15-07, 04:24 AM   #4  
Greg, even if the engine is overspeeding shouldn't there be a failsafe feature? Such as a regulator so as to not ruin any devices that may be plugged in at a time of mechanical failure? Other than a breaker, that is? Twisted99, have you measured the RPM's with a tachometer to know just what the engine is running at? If not then what does your ear tell you?

 
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08-19-07, 03:45 PM   #5  
Posted By: GregH The voltage increase would be expected when you "revved it".

A generator is meant to operate at a constant rpm.
The mechanical governor is meant to increase power to the engine when a load is applied but only to the preset rpm.

To test the generator output voltage you would not touch any engine controls.
Start the generator and plug a load in to see if the voltage changes.
So are you saying that as long as the gov. is working it won't "rev" on it's own and no damage will happen to the electrical appliances in the house? I know that it is supposed to run at a constant RPM. We only revved it when we noticed the lights dimming in the house when we started turning on circuits, we ONLY turned on lights, no appliances.

 
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08-19-07, 04:27 PM   #6  
The B&S generator may not have an automatic voltage regulator and your Honda might.
The quality of the power has a lot to do with how much you pay for it.

You didn't tell us the whole story as well.
If you say that the generator wouldn't maintain voltage with a light load then you may have freed the mechanical governor but it is still broken.

You really shouldn't use an unregulated generator on electronics because in addition to voltage control you have no guarantee the frequency control will be accurate.

These inexpensive generators are really only meant for the most basic of use.
If in a power outage your friend feels it is necessary to operate any electronics then he will need to pony up enough cash to buy a regulated generator.

How is the generator connected that you were turning on circuits?


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08-19-07, 05:31 PM   #7  
Posted By: GregH The B&S generator may not have an automatic voltage regulator and your Honda might.
The quality of the power has a lot to do with how much you pay for it.

You didn't tell us the whole story as well.
If you say that the generator wouldn't maintain voltage with a light load then you may have freed the mechanical governor but it is still broken.

You really shouldn't use an unregulated generator on electronics because in addition to voltage control you have no guarantee the frequency control will be accurate.

These inexpensive generators are really only meant for the most basic of use.
If in a power outage your friend feels it is necessary to operate any electronics then he will need to pony up enough cash to buy a regulated generator.

How is the generator connected that you were turning on circuits?
30amp cord to a flanged inlet, on a 30 amp breaker. Yes, there is an interlock.

 
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