Adjust Farymann engine speed

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rosssavage

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Hey all, I have a Farymann 15w powered gennie and would like to adjust the speed.

Off load engine speed is bang on 3000rpm (=50hz and 230v - it's a 230v spec unit, so that's perfect)

On load (approx 60% load, which is water heater and battery charger, and is my main usage regime) the rpm drops to 2954, 49hz and 215v.

I've replaced a duff crimp and the field capacitor as a matter of course, but really I guess the issue is low rpm on load. Being an induction gennie, output drops dramatically with a drop in rpm, so, how do I increase the on load rpm?

I've spoken to Fischer Panda (not the gennie manufacturer, but there is no uk dealer for Zeise Multipower any more...) and they suggest they set up their gennies to slightly over rev offload so they drop to the correct speed on load.

I've had a look at the Farymann manual, but it goes on about adjusting the governor, which really is not an easy DIY.

Does anyone have any experience or knowledge on tweaking the rpm without delving deep into the engine, as that's where the governor is (and needs special tools)? I can't believe there isn't a simple user adjustable something or other...

Thanks :)
 
You need to allow for 'Governor Droop'. This is the natural tendency that as the genny loads it will slow down. Unless you are running giant multi megawatt generators you have to live with it.

So with a reasonable load you are losing 1hz and 15v, so set the speed adjuster up with no load to produce say 245 v and around 51 or 52 hz. Then recheck with say 2/3 capacity and fine tune the speed control to 50 hz and ~ 230 volts.

Most appliances should tolerate these variations.
 
I've one here on the bench I'll take a look tomorrow, anyone need a good engine? I've got one here minus the generator end as its burnt out, everything else here including the sound shield.
 
Thanks for the replies chaps.

Yes, I'm happy to accept governor droop and increase engine speed a tad accordingly (as Fischer Panda do out the factory) but my issue is how to do it.

I've re-read the Farryman overhaul manual and it is possible to adjust speed by approx +/- 50 rpm by adjusting the governor full load spring pretension, BUT you need special tools to do it and they go to great lengths to insist it's a bench only job. I really, really don't want to take the gennie out for this, it's really stuffed away in the lazerette.

I just wondered if there was any way to adjust the throttle lever, which is effectively unused in a generator single speed installation but is still internally connected to the governor / pump system.

Ultimately, 215v is perfectly useable for the switched mode battery charger and immersion heater so it's no biggie, just be nice if there was a simple way to do it.

Still, if I mess with the governor and blow the engine, at least I know where to get a replacement from Paul!
 
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