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Droop settings on domestic generators

Droop settings on domestic generators

Droop settings on domestic generators

(OP)
Not so much a hobby question, rather more of a curiosity surrounding settings of standby generators, after recent experiences with Cyclone Ita and the fact that I work with much bigger versions of these sorts of things.

I've got a standby generator I picked up for a song second hand, managed to get it just in time so to speak, but the carby was full of crud, which meant that the cyclone preparation was more strenuous than it should have been.

I've got experience dealing in much larger sets, and automated controllers that make it pretty obvious as to what settings should be changed and when. Most (if not all) of our equipment runs load sharing equipment of one make or another, some via CANBus, some via analog sharing lines, but they all have different setpoints for the various functions (including droop).

Here's the question; during the process of pulling apart the carby, I got to thinking about how to adjust the thing for appropriate operation (it doesn't need to share load with anything else, obviously...) and what to adjust to get the thing to behave. I'm assuming it runs in droop, rather than isoch, this is partly due to observations that it ran around 52Hz at no load, though I didn't check to see how much it dropped under load.

I've heard mention that there are fairly typical settings for generators (say, 3% or 5% droop) but there's obviously no calibrated dial on the generator to adjust it. There's a fixed low speed idle adjustment (if all the pictures on the internet of the carby are accurate), and a linkage that appears to connect back to something on the tail end of the generator to automatically adjust itself.

The generator is a Chinese Honda clone with a nameplate that states 7.5kVA at 1.0PF...

Everything I deal with at work either has an actuator fitted to the fuel rack (e.g. Heinzmann on a Hino engine) or has some sort of ECM with an appropriate signal input (in which case the configuration and setpoints of the controlling unit become relevant).

Set runs well under load at the moment, doesn't idle real well, but I suspect that the reasons for that are due to the 'emergency' carby rebuild rather than fiddling with the settings on the carby. I'm aware that some here have far more experience in such things than I do and I'd appreciate some guidance on the background.

RE: Droop settings on domestic generators

I doubt that the droop will be adjustable. It will be inherent in the design. Some smaller engines used a vane in the cooling air flow for speed control. A spring holds the throttle full open. As the speed increases and the air flow increases, the force on the vane increases until it balances the spring force and the linkage starts to pull the throttle closed. Good enough for lawn movers and such applications.
Better quality motors may have a fly-ball type of governor inside the crankcase. Again the throttle is pulled full open with a spring and pulled closed against spring tension by the governor. Speed is controlled by spring tension. Droop is not adjustable.
Automatic idle may have a solenoid somewhere in the linkage.
52 Hz may be 4% droop, 3% droop with the speed set a little high, or something else.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Droop settings on domestic generators

(OP)
Thanks, waross, I had thought that would have been one of the possibilities, as there's not likely much benefit in playing with it.

RE: Droop settings on domestic generators

Your droop on a stand-alone generator won't really affect anything: Unless it is so far out-of-kilter that (at high amp loads) the droop setting means that there isn't enough voltage to run the gadgets you want. And that isn't very likely.

Different droop setting would significantly affect two generators trying to share any load.

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