What voltage does your generator run at?

[TomSeller]

I picked up a nice 7500W Gillette generator a while back cheap off of CL with a Honda GX engine that had a simple carb problem. With the carb problem fixed I measured the "120V output" at 110V and steady +-.02V with my Fluke 112 meter. My commercial power runs at 123V on the same meter. I have not checked yet if the voltage regulator is adjustable but was curious what voltage people run at.

 

[Stimw]

You need to adjust the governed speed up to 120 V and check it with a load.

 

[JerryK]

The important thing is the ' cycles per second '. Voltage is really somewhat meaningless measurement, which varies with load, and only has to be in a certain range. Even your house voltage varies depending on how much current you, your neighbors, and the other folks around you are using. The electric company attempts to place a voltage on the high side of your residential transformer that will give you a certain range of voltage going to your house. But the cycles stay at 60 per second. They make meters to set up generators by measuring the cycles per second... which is what you are changing by adjusting the motor RPM...

 

[Gary Fowler]

What JerryK said. While voltage is important, setting your generator to 60 cycles per sec (CPS) is the way to set them. All the high priced commercial generators will have a meter to register both voltage and CPS but the engine RPM's is set by bringing the engine speed up till the 60 CPS is reached. Once this is set the voltage should be 120V + or - 10 volts and 220-240 volts on the high voltage terminal.

 

[TomSeller]

Excellent advice. My Fluke meter can toggle to Hz so I will use that when setting the voltage regulator, assuming it can be set. Gillette seems to be a commercial brand so at this point I assume I can. The regulators are usually under the cover at the end of the generator, correct?

Gillette Generators | Standby & Portable Generators

 

[CCWKen]

I think I'd disagree. Depends on what you're going to run on it. Voltage is just as important as Hz if you're running motors or electronics. That 110v could drop to less than 80v under a load and cook motors where less than 60Hz will just make them a little noisy. Electronics will just stop working. Not good for delicate stuff. Most everything will tolerate +/_ 5% voltage but not less. And products today usually tolerate 50/60Hz without problems.

 

[TomSeller]

I am going to use this to power the generator circuits in the house so lights, refrigerator, TV, fart fans, that type of thing. No big loads but since it is listed at 6%THD it is better than my other house generator. I have a diesel generator I use around the farm for motors, tools etc.

 

[Stimw]

Cycles check is great BUT when he messed with the carb he probably got the governed speed off.
Being used anyone could have changed the setting.
By correcting the speed the cycles should come back.
I was a Honda Small Engine Dealer for 15 years, carburetor work can/will alter set RPM.

 

[TomSeller]

Cycles check is great BUT when he messed with the carb he probably got the governed speed off.
Being used anyone could have changed the setting.
By correcting the speed the cycles should come back.
I was a Honda Small Engine Dealer for 15 years, carburetor work can/will alter set RPM.

No, it ran rough prior to doing anything with the carburetor and I measured it around the same voltage output the last time I ran it. The throttle is governed by the regulator, so all that changed is that it now runs smooth.

What do you mean by "Cycles check is great BUT when he messed with the carb he probably got the governed speed off" ? Cycles per second is "speed", no?

 

[RNeumann]

I think I'd disagree. Depends on what you're going to run on it. Voltage is just as important as Hz if you're running motors or electronics. That 110v could drop to less than 80v under a load and cook motors where less than 60Hz will just make them a little noisy. Electronics will just stop working. Not good for delicate stuff. Most everything will tolerate +/_ 5% voltage but not less. And products today usually tolerate 50/60Hz without problems.

Yep getting the gen to run at the proper voltage will be cheaper than a new refer. You need to get the voltage up to 120-123 at the unit.

 

[JerryK]

Most home owner generators run at 3600 RPM's. Other popular RPM's on bigger units is 1800 [ not as annoying ]. Anyone that has spent long times listening to the 60 cycle hum or around a running generator could probably set the proper RPM from sound memory..... Once your get the motor running at the proper speed [ or near it ], your voltage should read up around 120/240 volts RMS [ what your Fluke measures, that and their DC accuracy is what made Fluke famous ] without a load, plus or minus a handful or so of volts. As you place a load on the generator, the voltage tends to get lower.... just like in your home with store bought power from the electric company.

 

[90cummins]

HZ & Voltage are interdependent.
On most generators the correct voltage is attained when the engine is running at the correct speed.
Low engine speed = low voltage.
Anyone using a portable generator should have a Killawatt meter to monitor Hz & voltage anytime it is being used to power your home.
Stand-by units have over/under voltage & frequency shutdown protection unlike portables.
When ever I service or repair a unit I check the Hz and voltage and have found low voltage in more than a few because of a bad capacitor.
The owner was totally unaware of the problem but left unchecked could have damaged expensive electronics.
Motors in freezers & refrigerator's are very voltage sensitive.
No portable generator provides perfect 60Hz 120/240 volt power, there are limits on both you need to be aware of.
I used my Kilawatt meter to measure the current draw (watts) on all my electronics so there is no guessing about capacity when I use a device.
My 2 cents
90cummins

 

[buickanddeere]

Some generators use a cheap and awful system of field excitation with a rectifier instead of a regulator. I have a crappy Generac with no load voltage is too high at 145 volts and full load voltage is too low at 102volts. I have a proper aftermarket regulator on the bench to install someday .

 

[TractorGuy]

Not sure how this relates but my diesel generator adjusts voltage through a solid state regulator with potentiometers. I adjust the hertz by adjusting the governor speed of the engine.

My utility power measures 248v, 60 hz at the panel so I try to match that at the genset. My hertz will drop a little under load so I set the no load hertz to 61.5. At 40 amps load it drops to around 59.8 hz. My voltage remains constant at any load.

 

[daybreak1998]

Howdy,
You want 60Hz, the voltage can be in a range from 110-120volts. UL rating makes manufacturers build in usage of a guaranteed reference variation of 5%. Manufacturers build in usually 7% variance to ensure the products work as advertised. When someone speaks of a voltage of a products, they could say its a 110 volt unit. You might find things saying its a 115 volt product. You will also see it called 120 volt. Do not get all hung up on the voltage. The most important is going to be Hz. USA products are made for 60Hz. Just because someone says a clock plugged in to 50Hz will just run slow. That is a very simple powered item. Your refrigerator was made for 60Hz. It will end up dying if you keep running it on 50Hz. There are a lot of household items which do not care about Hz. Standard incandescent light bulb. That is not the only thing using power in your house. Have you looked at the outbound 30amp socket on your unit? it probably says 30 amp 125/250 on it.

A good clean 60Hz and 115volts is fine.

 

[TomSeller]

Not sure how this relates but my diesel generator adjusts voltage through a solid state regulator with potentiometers. I adjust the hertz by adjusting the governor speed of the engine.
.

So adjust the governor on the engine to get 60 Hz out of the generator, then adjust the potentiometer on the voltage regulator to 120/240V out of the generator? Then check under load?

 

[Mendonsy]

So adjust the governor on the engine to get 60 Hz out of the generator, then adjust the potentiometer on the voltage regulator to 120/240V out of the generator? Then check under load?

Yes, that is the best procedure.
The frequency tolerance is 5% so 57-63hz is the range. You want to start with about 62hz at no load because it will drop a bit as the engine is loaded up.
Voltage is the same deal. If your generator has a voltage adjustment then set it for 125 volts at no load. It will drop some as the generator load is increased.

 

[JerryK]

Always remember that the important voltage is what you actually provide the device you are powering. Long extension cords, poor connections/worn out plugs or even house wiring, may be delivering too low of a voltage to the frig/pump/etc.

 

[techman]

A couple of points. Generators fall into 2 categories. One type have (electronic) regulators. They have a board which will have an adjustment to set voltage. This type will maintain voltage under varying load and frequencies. They are the "better" and generally more expensive generator. The other type are "self regulating" generators. They will have one or more capacitors connected to the generator. This type of generator has a voltage to frequency relationship and are configured for a nominal voltage at the desired frequency (60 hz typical). Faster (higher frequency) will output higher voltage and vice versa. The only way to change the relationship is by capacitor value change. With this type regulation is not as good. If the voltage is low (or high) it typically indicated that the capacitor is out of tolerance or going bad, and should be replaced with a new one of the proper value. This type of generator is usually lower cost.

One other point. It was mentioned that US specs the voltage and frequency. UL does not require or set the requirements of these values.

paul

 

[TomSeller]

My house (built in 1988 ) had the "Quickwire" push in terminals when I bought It in 2015. I dislike those for load carrying circuits. So I have now replaced all of the primary feed circuit outlets but have 20 or so "bedroom" type load outlets to go at some point. Wire size seems to be All 12+ AWG so I should not have much voltage drop going on.