Portable generator voltage outputs

[SPARKS40]

I have a buddy of mine who just bought a portable 5500 watt generator. He fired it up and was checking the voltage with my Fluke 117 that he had borrowed and was getting a reading of 130-133 volts on each leg with no load. Is this typical of the portables to emit a slightly higher voltage, or is there something wrong with the genny? I figured that under load it should be okay, but he's wanting to be able to run his furnace off it, as well as lights, fridge, chest freezer, A/C, etc. Should it be an issue for any electronics run off it, or should it be limited to the essentials, such as lights and refrigeration equipment? What should be the maximum acceptable voltage output?

 

[mxslick]

No it is NOT ok as is. No-load voltage should be in the range of 115-120 volts. Connecting any load with electronics at that voltage is likely to let the magic smoke out.

The generator is running a bit too fast which is why the voltage is high. (And yes the frequency will be bit off too.)

Depending on the make and model of genny the speed would be adjusted by repositioning a spring in a different hole on the throttle/governor assembly, by a screw-type idle stop, or if electronic governed there will be a trimpot.

My advice is, if it isn't obvious how to reset the speed, take it to a shop that serviced generators and let them adjust it. It won't cost much and will be worth it.

 

[SPARKS40]

Thanks for the fast response. I didn't think it was kosher, but i'm all for getting 2nd opinions. I'll take a look at it tomorrow, and if i can't fix it for him i'll tell him to take it in.

 

[SPARKS40]

The genny in question is a Briggs & Stratton Powerboss, model 030249 if that helps anything. I just looked at the manual online, and there doesn't appear to be any way of adjusting the output. It specifically states not to attempt to adjust the governor, but i'm thinking maybe i can adjust the throttle screw and see if that does it. It was brand new right out of the box, so i can't really see it being defective.

 

[quogueelectric]

try putting a resistive load on it then remeasure the output. a clothes iron for example before you start turning screws. call the manufacturer and ask for their advise. some gensets have output voltage screws or knobs/dials.

 

[electricmanscott]

try putting a resistive load on it then remeasure the output. a clothes iron for example before you start turning screws. call the manufacturer and ask for their advise. some gensets have output voltage screws or knobs/dials.

Good advice.

It would be very unwise to start messing around with this.

 

[jumper]

It was brand new right out of the box, so i can't really see it being defective.

I can, that is why they have warranties. You have done your buddy a favor already by checking the voltage. Tell him to just take it back and get another one.

 

[LEO2854]

I have a buddy of mine who just bought a portable 5500 watt generator. He fired it up and was checking the voltage with my Fluke 117 that he had borrowed and was getting a reading of 130-133 volts on each leg with no load. Is this typical of the portables to emit a slightly higher voltage, or is there something wrong with the genny? I figured that under load it should be okay, but he's wanting to be able to run his furnace off it, as well as lights, fridge, chest freezer, A/C, etc. Should it be an issue for any electronics run off it, or should it be limited to the essentials, such as lights and refrigeration equipment? What should be the maximum acceptable voltage output?

If it is brand new take it back for another one.
Have them start the new one right at the store and check the voltage.
If they won't do that then just take the refund and buy a generator at a place that does repairs on site usualy when you buy equment at a place like that they will start the equipment for you and go over its operation it's worth a few more bucks to buy something you know is working in the first place.

 

[ceb58]

try putting a resistive load on it then remeasure the output. a clothes iron for example before you start turning screws. call the manufacturer and ask for their advise. some gensets have output voltage screws or knobs/dials.

Agreed, Put a restive load on it and check voltage. My 5500w gen. runs higher voltage with no load also but it comes into range with a load due to the electronic voltage regulator. Never had a problem with the issue. I think the regulator is set this way to keep from having a voltage drop on start up of the equipment.
If the unit is still putting out high volts with a good load then I would not adjust any thing due to warranty. The only catch to it is most places will not take a gen. back after it has been used but they should have some one to do the warranty work.

 

[mtfallsmikey]

Could be the voltage regulator module is bad...

 

[hurk27]

make sure you use more then one meter, weak battery's in some DVMs can cause a higher reading, I have seen this high of a reading from the utility without a problem. to see if the generator is over speeding, check the frequency, if over 60 hz then it over speed, if its at 60 hz, its over excited and will require voltage regulator adjustment to be done. as was said, take it back if you confirm the over voltage/frequency

 

[roger]

but he's wanting to be able to run his furnace off it, as well as lights, fridge, chest freezer, A/C, etc.

It is doubtfull that a 5500 watt generator will be able to start all of these loads when others are running. He will most likely have to shed some of the motor/compressor loads for others and depending on the size of the A/C the generator may not be able to start it at all

Roger