Diesel Power Generator Question

[BHD]

the Rpm of a generator head is

3600 RPM @ 60 cycle for a two pole,
1800 RPM @ 60 cycle for a 4 pole,
1200 RPM @ 60 cycles for a 6 pole generator

 

[franklin2]

the Rpm of a generator head is

3600 RPM @ 60 cycle for a two pole,
1800 RPM @ 60 cycle for a 4 pole,
1200 RPM @ 60 cycles for a 6 pole generator

3200rpm is what came out of the owners manual. That must have been the engine rpm, and they had a certain size pulley on the engine to make it work out, since what you are saying makes sense. I don't have the original pulley that came with the Honda engine. Somehow it all worked out with what I have.

 

[buickanddeere]

The generator's head rpm has to stay at 3600, 1800, 1200 or what ever is required to make 60HZ.
The engine and generator slowing down is not acceptable.
There is not enough savings in fuel or wear to make it worth belting rpms to operate the engine at half rpms.
1800rpm is minimum rpm to operate that engine . Lower rpms and making the engine work will over heat an air cooled engine. It was engineered to operate with that cooling fan up to rates rpm.

 

[buickanddeere]

10KW or 12.5KW would be a good match with 16HP. I don't like operating small generators at or near max nameplate capacity. Manufactures are often optimistic on their equipments capacity. Or the capacity is a peak or intermittent rating.

 

[Kubotafan]

I have herd that a regular generator makes "dirty power" with more variance in power and an inverter generator "clean power" with less variance. If a regular generator is used and only operating at 2/3 or 3/4 of its capacity does this make less variance in the power generated?

 

[franklin2]

The generator's head rpm has to stay at 3600, 1800, 1200 or what ever is required to make 60HZ.
The engine and generator slowing down is not acceptable.
There is not enough savings in fuel or wear to make it worth belting rpms to operate the engine at half rpms.
1800rpm is minimum rpm to operate that engine . Lower rpms and making the engine work will over heat an air cooled engine. It was engineered to operate with that cooling fan up to rates rpm.

In my case, I am using a 20hp diesel engine to run a generator that used to have a gas engine rated around 10hp. It seems very happy to run at 1500rpm running that little 4.5kw generator. It has a hz meter on it but it's broken. It would be nice if I could fab up a control panel that had a nice voltmeter and some other type of setup to measure the frequency. I already have plans to give the generator a permanent home beside my garage with a little roof over it to keep the weather out. When the power goes out, I can take the mower off the tractor and drive up to the side of the garage and hook up the pto and let it run.

 

[bigdeano]

Harbor freight has a 7200 watt 3600 rpm generator head on sale for $300. Get some cast iron pulleys from surplus center, build a frame and you're almost done.

I built a generator with an Isuzu diesel car engine and a 10kw gen head. It's worked very well. I had to machine a shaft to mount a pulley to the flywheel. It's some work to make, but it was worth it.

 

[Groo]

I bought a old Honda 4.5kw generator that had a blown engine. It was one of those really old units that used a belt between the engine and the generator.

I have a f2000 kubota mower with a 72" deck. I wanted to use that to power the generator. A long time ago the Surplus Center had mower deck driveshafts and one of them plugged right into my pto. I took the blown engine off, used two pillow block bearings and a shaft with brackets and mounted all that in place of the blown engine with a new belt.

Then came the calculations for rpm. First off, my engine is 20hp. This generator would not need all that horsepower, and I didn't want it screaming at high rpms constantly wasting fuel while running the generator. With the 72" deck still on it, I played with the rpms to see where the best spot was were the engine seemed to have power and the governor could kick in when it needed. I found I could run the engine at about 1600rpm, and it still seemed to react ok to a load.

I then measured the pto speed, and in high, the pto speed was exactly the same as the engine speed. The specs on the honda generator called for 3200 rpm for 60hz full output operation. So I knew I needed to double the speed of the shaft I installed.

I measured the pulley diameter at the generator, and it was 5 inches, so I knew I needed a 10 inch pulley for the drive. I called some local places and they wanted right much money for the proper pulley, and by the time I paid shipping from the Surplus Center, it would have been close to the same price. So I went to tractor supply, they have those universal pulleys where you weld in the hub. All they had was a 12 inch, so being cheap I bought it.

Theoretically the 12 inch is too big,, but in reality it works ok. I still run it at around 1600 rpm, and when a load is put on it, the tractor slows to about 1450-1500rpm. It seems to work fine, I have used it already during one power outage. And with the 5+ gallon tank, it should run a long time like this without needing re-fueling.

some electronics are real sensitive to "bad" power. Dad's cordless tool charger wont run on his generator, but motors are fine.