Generac Q55G 146VAC output

[sCarycary]

My genny is putting out 146V. It should be closer 120V. The genny stays running but my outlets shut down for a monute or so and then resets and I get power back for a short while. I suspect the voltage regulator on the genny. What do you think it is?
Cary

[sCarycary]

This morning it was putting out 118VAC while I was making coffee. I suspect an electronic component that heats up and is breaking down.

[joshuajim]

Is the 146v a no load voltage? Some generators run “wild” on voltage until a load is applied.

[PbdBlue]

The governor needs to be adjusted. It's normal for the voltage to be lower under load (i.e making coffee). If I recall the no load is supposed to be around 130VAC and as mentioned it will be lower under load. The specs are in the service manual. If you can't get it to adjust properly then the governor spring may need to be replaced. Also clean and lube all the linkage points.

[sCarycary]

Originally Posted by joshuajim

Is the 146v a no load voltage? Some generators run “wild” on voltage until a load is applied.

Yes that was no load. It was cycling off & on with 146v output. This morning, no load was 118v, 5v drop with toaster & microwave running. I'll run it for a longer period of time today and see if it acts up.

[Charlie 5320]

Originally Posted by sCarycary

Yes that was no load. It was cycling off & on with 146v output. This morning, no load was 118v, 5v drop with toaster & microwave running. I'll run it for a longer period of time today and see if it acts up.

Take it to a Generac dealer to have it serviced. You don't have a way to set the rpm of the generator head. It needs to be set to a certain RPM, then the voltage regulator can be adjusted. DON'T start messing with the governor. If you take the plastic cover off around the switches, the regulator is in there. It has 5 or 6 wires going to it, there is a little blue and white pod that can be adjusted for voltage. Set it to 123 to 128 vac unloaded, then load it up. You don't want it to go below 118 vac loaded. If you can't get this vac take it to a service dealer, you WILL be money ahead. The generac does NOT have a fast warm up like onans do.

[Bob Hyatt]

Originally Posted by PbdBlue

The governor needs to be adjusted. It's normal for the voltage to be lower under load (i.e making coffee). If I recall the no load is supposed to be around 130VAC and as mentioned it will be lower under load. The specs are in the service manual. If you can't get it to adjust properly then the governor spring may need to be replaced. Also clean and lube all the linkage points.

The governor is ONLY about frequency (60 hz). The generator part of the genset produces the voltage as demanded by internal settings. Not quite sure how you would get that high a number even unloaded. I have a 7.0 in my coach, and a 7.5 generator (Westinghouse) at home. Neither has that kind of an issue. Only problem with any of these is that unloaded, the generator spins easier, and that will screw up the frequency a bit, making it higher since it is spinning faster than the existing number of poles on the armature should spin to produce 60hz. That is why cheaper generators are a problem in that voltage fluctuates, frequency fluctuates, and some electronics fail to see any humor in those conditions.

SO, that being said, check the frequency it is producing. Too high, governor is improperly adjusted which will also screw up voltage. Frequency correct means it is not a generator fault. Just always check with a reasonable load, otherwise the generator will tend to overspeed a bit under no-load conditions and give you too much of both. If you spin it at (say) 3600 for a 6 pole alternator, you will get exactly 60hz and exactly the voltage the field coils were wound for (125v for any I have measured).

[Charlie 5320]

Originally Posted by Bob Hyatt

The governor is ONLY about frequency (60 hz). The generator part of the genset produces the voltage as demanded by internal settings. Not quite sure how you would get that high a number even unloaded. I have a 7.0 in my coach, and a 7.5 generator (Westinghouse) at home. Neither has that kind of an issue. Only problem with any of these is that unloaded, the generator spins easier, and that will screw up the frequency a bit, making it higher since it is spinning faster than the existing number of poles on the armature should spin to produce 60hz. That is why cheaper generators are a problem in that voltage fluctuates, frequency fluctuates, and some electronics fail to see any humor in those conditions.

SO, that being said, check the frequency it is producing. Too high, governor is improperly adjusted which will also screw up voltage. Frequency correct means it is not a generator fault. Just always check with a reasonable load, otherwise the generator will tend to overspeed a bit under no-load conditions and give you too much of both. If you spin it at (say) 3600 for a 6 pole alternator, you will get exactly 60hz and exactly the voltage the field coils were wound for (125v for any I have measured).

Best not to give information when you clearly don't have knowledge of said equipment.

The generac in question is a 2 pole generator.

The engine speed should be 2570 to get a rotor speed of 3600 RPM.
Adjustment of the regulators " voltage adjustment" potentlometer must be done only when the unit is running at it's correct governed no-load speed. Speed is correct when the units no-load AC output frequency is about 61-63 hertz. At the stated frequency, AC output voltage should be about 122 to 126 volts.

This is directly from the service manual for this generator.

The easiest way to screw the generator up is start messing with the governor.

Don't do it.

[PbdBlue]

Originally Posted by Bob Hyatt

The governor is ONLY about frequency (60 hz). The generator part of the genset produces the voltage as demanded by internal settings. Not quite sure how you would get that high a number even unloaded. I have a 7.0 in my coach, and a 7.5 generator (Westinghouse) at home. Neither has that kind of an issue. Only problem with any of these is that unloaded, the generator spins easier, and that will screw up the frequency a bit, making it higher since it is spinning faster than the existing number of poles on the armature should spin to produce 60hz. That is why cheaper generators are a problem in that voltage fluctuates, frequency fluctuates, and some electronics fail to see any humor in those conditions.

SO, that being said, check the frequency it is producing. Too high, governor is improperly adjusted which will also screw up voltage. Frequency correct means it is not a generator fault. Just always check with a reasonable load, otherwise the generator will tend to overspeed a bit under no-load conditions and give you too much of both. If you spin it at (say) 3600 for a 6 pole alternator, you will get exactly 60hz and exactly the voltage the field coils were wound for (125v for any I have measured).

My mistake. I misread the title. Thought we were talking about an older Onan. On the older Onan’s the voltage is dependent on the governor setting. There is no separate voltage regulator. The frequency varies with the voltage.

[sCarycary]

Current plan is to replace the voltage regulator in the generac. I measured the voltage at the main AC breaker at 156V during fault condition. The rpm sounds the same wether the voltage is 118 or 156.

[Charlie 5320]

Originally Posted by sCarycary

Current plan is to replace the voltage regulator in the generac. I measured the voltage at the main AC breaker at 156V during fault condition. The rpm sounds the same wether the voltage is 118 or 156.

Use a meter to find out the HERTZ, if 60 to 62 use the pod on the regulator to adjust the voltage. You need to down load the service manual for your generator. I found them on line while working on my own generac. Chances are a new regulator will need to be adjusted also. Every one I've replaced needed to be adjusted. I have a generac NP66 set up for an emergency generator for my house.

[ssiron]

I've started having problems with my generator transferring. After starting it will shortly transfer but the voltage is very high. It drops to zero after a moment, but the engine continues to run but zero voltage. The only thing I could guess it might be is a voltage regulator failure. Has there been a problem with voltage regulators failing. My generator is 20+ years old. I don't run it much other than to exercise it every 2 or 3 months. Lately I have been having some problem with the transfer switch not operating every time. That's what I was going to address when the voltage problem started. As I started to check in the generator panel I found some other problems that I need to fix before I continue to find the voltage problem. The shock vibration mounts on the control panel have failed. Found some and ordered. Any thoughts where to start would be appreciated.
Frank

[sCarycary]

Originally Posted by ssiron

I've started having problems with my generator transferring. After starting it will shortly transfer but the voltage is very high. It drops to zero after a moment, but the engine continues to run but zero voltage. The only thing I could guess it might be is a voltage regulator failure. Has there been a problem with voltage regulators failing. My generator is 20+ years old. I don't run it much other than to exercise it every 2 or 3 months. Lately I have been having some problem with the transfer switch not operating every time. That's what I was going to address when the voltage problem started. As I started to check in the generator panel I found some other problems that I need to fix before I continue to find the voltage problem. The shock vibration mounts on the control panel have failed. Found some and ordered. Any thoughts where to start would be appreciated.
Frank

I replaced the voltage regulator on the generator. The voltage going into my convertor/inverter was high(140-150VAC) intermitenrly. The motor speed was steady. The voltage regulator was the most likely bad part. About $100 to replace.