803A dropping from 60hz to 56hz under 25% load.

[Leonardo]

So I have an 803A that I used during hurricane helene. She worked great except I noticed that the frequency drops from 60hz to 56hz when my water heater is on. Load meter only shows a 25% load during this condition, so I doubt it's a load issue. I think this is a governor issue because I found if I turn the frequency adjusting knob to up 64hz unloaded, then the generator drops to 60hz under the load of the water heater. This tells me that it isn't a fuel issue or some sort of lack of power problem. The generator has the power to run my water heater at 60hz, but it drops by 4hz under load. Is there a way to adjust this?

I seem to recall something about a droop screw for adjusting frequency droop but I can't seem to find any reference to this. Wondering if you guys might have the answer.

 

[DieselAddict]

Is this a new problem? Has it ever held RPM correctly with load?

How many hours on the set? How long have you had it?

Any smoke from the exhaust at an indicated 25% load?

 

[Leonardo]

Thanks for the reply. Machine had a rebuild tag indicating it was gone through about some years ago. It has 400ish hours on the hour meter, and I don't remember if it had this problem before, maybe I just never noticed it. I only have about 100 hours of run time on this generator.
Other then this issue, it runs great. Just sips fuel so nice and economical. It doesn't need any oil between oil changes. Engine sounds great, no weird noises or smells. I've gone through the unit and changed all the various filters. Done the MOV mod. It already had the stator fuse installed when I got it.


I also verified the frequency and voltage readings on the control panel are correct with 2 different kill a watt maters plugged into my house, one on each leg of the breaker. So it's not a control panel issue.

 

[Ray70]

Droop adjustment is covered in the TM. The screw is located on the front of the fuel rack and is accessed through a plug on the oil filter side of the timing gear cover. You use an Allen wrench ( hex key ) to adjust. If everything checks out fuel delivery wise and there is no smoke when the engine droops and you can get the speed back in range with the knob while under load, my guess is the governor is out of adjustment.

 

[Ray70]

 

[Leonardo]

My man! That's what I was looking for! You are correct that there is no smoke when it drops hz under load.

 

[Jeepadict]

Wow, thanks for posting this! I have a low hour 802 that drops frequency as the load increases, I could always compensate with the adjustment knob. It never registered in my mind that it needs an adjustment, just been added to the to-do list. @Ray70 I appreciate the refrence docs!

Sent from my SM-G970U using Tapatalk

 

[Ray70]

No problem, screen shots are from the -24 general support and maintenance manual.
Table 1-2 calls for 3% on the frequency regulation, so ~ 2Hz droop at full load is about the acceptable range.
If you turn the screw clockwise, decreasing the droop, but then start to find the engine RPM hunting up and down at no load or after the load is dropped, that means you went too far. Back the screw out just enough to stop the hunting and you'll be set perfectly.

 

[Guyfang]

And test, test, test when you THINK you are done.

 

[Leonardo]

It works! I can maintain 60hz now no matter if I am unloaded, at 25% load, or at 75% load. I can run the hot water heater and the central a/c at the same time and it still shows 60hz.

Thanks again.

 

[Light in the Dark]

The more you learn about the machine, the more one comes to appreciate what it is (and what it isn't). Might not be the world's most advanced engine design... but there's something to be said for that!

 

[Guyfang]

New, is not always better.

 

[WWRD99]

View attachment 933957

View attachment 933958

What is the accepted droop amount? I can put a 75% load and it drops 2 lines on the hertz gauge. I did do one clockwise turn on the governor. It was worse before. It does not hunt or smoke. Is there a page in the tm that shows that? I didn't find it. 803a too.

 

[DieselAddict]

Its typical to see about 1.5hz drop from zero load to full load.

 

[Light in the Dark]

What is the accepted droop amount? I can put a 75% load and it drops 2 lines on the hertz gauge. I did do one clockwise turn on the governor. It was worse before. It does not hunt or smoke. Is there a page in the tm that shows that? I didn't find it. 803a too.

Should be a max of 3% of rated frequency, which would work out to 1.8hz. You are well within spec.

 

[DieselAddict]

The important thing is that droop is a necessary part of governor function. Less is NOT better. It leads to surging if you try to get it too low.

 

[WWRD99]

This group ROCKS!! I didn't know there was an adjustment for this. Just lived with it. I think I will leave it where it is then. I can hit from 25 to 80 when the dryer coil turns on. It drops the about 2 lines and stays there. Sits right at 60 with the 25% load. Seems to be a happy medium because I do not want hunting. It used to drop about 5 lines and I'd adjust the cable to inbetween high and low...it went above 60 by a few lines then dropped a few lines. Now it's solid with a 2 line droop. Again can't thank you all enough on the knowledge you all share.

 

[Ray70]

One other minor note, when running your machine you want to set the throttle a little above 60hz. at no load.
Most of us start between 61 and 61.5 at no load, thus dropping to about 59 to 59.5 at full load.