Ever run a generator with a Bolens/Iseki?

[Rod in Forfar]

My 5 kw Honda generator's in the shop, so I'm thinking about a 7 kw pto generator to attach to my Bolens G174. The engine is strong and might be a good match for the generator. The setup appeals because of the Bolens's low fuel consumption when under load.

But according to the manual 1st gear turns the shaft at 472 rpm at 2700 engine rev's. 2nd gear offers 752 at the same speed. That would run the engine at 1938 rpm. How would the torque and governor response be at that speed? It would be quiet enough.

I've read some dire warnings about running generators with idling tractors turning the pto at 1000 rpm, but I wonder what readers have found in real-life with compact tractors with three pto gears?

(The mower and the bush hog prefer 2nd gear. The 2 cylinder Bolens doesn't have a tach, btw.)

 

[Ilikeurtractor]

If anyone has the horsepower/torque curves for the Mitsubishi KE75 (which I am implying you have), it would help a lot here. I have them for the K3A/B series engines, but I have no idea about the two cylinder engines but wish I did.

You should be able to use the generator frequency to help gauge engine speed since you don't have a tach (if I'm reading your post correctly). Something as simple as one of those "Kill-a-watt" meters will display frequency when plugged into the generator if it doesn't already have a meter on it. I'm assuming the generator has some sort of step-up gear box to turn 900/1800/3600 rpm with a 540 input speed to get to 60 Hz on the electrical side.

My gut feeling is that you should be able to squeeze out at least 4 kW from this setup and possibly up to 6 kW which would be a pretty good match. The KE75 is claimed to have about 15 hp at the PTO at peak power. Since you'll need to operate at around 2000 rpm you'll be slightly below peak hp on the engine. Not sure on generator efficiency, but a good rule of thumb is that you'll need 2hp for every 1kW of electrical power for direct-drive units. If you are going through another gearbox to get to the generator rotor, you'll probably lose another 20% (or require about 2.5hp/kW). So if you have about 12 hp going into the generator, expect around 5 kW output.

I'm thinking the governor on the engine is not well suited for maintaining good stability on the shaft speed. Certainly report back any findings. It would be great to know for sure. Sounds like a fun project. Good luck :thumbsup:

 

[Rod in Forfar]

Thanks for the comment. I may not buy the generator.

Turns out my 5 KW Honda EM is fine, just choked on some varnish. For years it has sat intact with stabilized gas. A spring dock project, though, and two summers forgotten without stabilizer, and it couldn't find any fuel to burn. An hour of tech time's all it took.

I'd still like to experiment with the 7 kw Winco generator, so I made a low-ball offer on it. If the deal goes through I'll likely write a series of blogs on the subject.

Any way to post the torque curve of the engine you mentioned?

Rod

 

[Ilikeurtractor]

K3A and B power/fuel consumption/torque curves attached.

 

[Rod in Forfar]

If this is a common pattern for small tractor diesels, the 2000 rpm level might not be bad at all. Interesting how the fuel consumption graph curves. My 2 cylinder KE 75 definitely has a sweet spot at about that speed, though it's pretty smooth throughout its rev range. Thanks for the graphs.

Rod