PTO generator horsepower.

I bought a Winpower PTO generator to use with the old Lincoln buzz box building corner braces, etc. Best I can tell it is a 25 KW. If it were needed to put out something close to that what kind of horsepower would it suck? It's overkill but I got a good deal. Just curious about requirements.

Would I be better off with a diesel on it? They seem to have a little tighter governor parameters than an old gas tractor. It would be handy to have it just hooked to one of my old gas tractors that isn't in high use. I guess the old buzz box isn't going to go haywire about a small amount of fluctuation. That would be a lot easier than using a field or chore tractor.

It is 25 KW X 1.5 = 37.5 HP assuming no losses

I would want at least 45 PTO HP

A simple calculation including losses and a little extra is 2 HP per 1KW. In your case 50 HP for a 25 KW Gen My guess is that you won't need that much power and a tractor with half that HP would run most households with no problem.

Use to run one with a 800 Case diesel when we milked. With everything in the barn going and the house heat on, it would work the 800 pretty good. We could only have lites on in the barn when running the silo unloader. 800 Case was about 50 horse, 25 KW generator.

I"ve had the 25/45 KW unit since 1977. Typically had it on the 53 pto hp D17, or the 70 pto hp 3020. Maximum single motor I had to start was a 10 hp on the manure pump, then start the 3? hp on the barn cleaner. Usually running the two 5hp motors on the vacuum pumps at the same time. Feeding had to wait til after milking- too many 5- 7 1/2 hp motors to run then. Gave the D17 a good workout, but didn"t phase (pun intended) the 3020.

As DavidG pointed out. 38 pto HP would be demanded with a steady 25Kw load.

And of course, if you're running 1/8" 6011 at 100 amps you're drawing about 4 kw.

I can't remember, do you still have an M sized Farmall? It should do fine for that running a welder. They have quite a bit of rotating weight for the HP size and you'll have plenty of momentum at high idle. I agree that a few Hertz more or less isn't going to hurt a plain old welder.

Yup, that was just the one I had in mind. It's been relegated to mixer grinder duty and a few other odds and ends. It would do it good to run the generator in the field.

Running just a welder a super h or 300 would do it. That's what we usually used on ours to run the grain elevator.
Houses, barn, and related equipment is going to take a little more.

I was told 2hp/kw also. I used to run my 50hp massey that I don't have anymore on a 15kw. All it would do is make the engine slightly sound different when flipping the breaker, then acted like almost no load at all.

1 KW equals 1.34 hp. so at 25 KW you are putting out 33.5 hp. however when it comes to generators, the rule of thumb i've heard is to provide 2 hp per kw. the important thing is to keep rpms steady no matter what the load. let the circuit breaker be the limiting factor, not the engine.

I think Winco recommended 45 hp for the 25 kw one I had at one time.

That said, the one time I tried using it with a welder I burned out a rectifier in the generator.

The 2 to 1 rule of thumb is to provide reserve on the prime mover to power the generator through momentary overloads.
As said before the mechanical input to the generator is 38HP to produce 25kw of electrical output given typical generator efficiency.
Any other non electrical trained and experienced persons wish to weigh in with "what they heard from Bubba" ?

Lets put it this way.... 25 KW = 37 HP. (26/.675) That is the maximum output of the generator. I've never seen a generator or anything else that was 100% efficient. The usual factor I was taught to apply was 85% efficiency.... So take that 37hp and divide again y .85..... and now you're up to 43.5 HP input to spin the gen at maximum output. Then factor in that the gen may possibly produce more than the rated 100 amps output depending on how well the circuit breaker actually works and also depending on how fast you actually spin the gen.... You spin it faster and it makes more voltage... thus it makes more power... and takes more power.
The 2 hp per KW was always a rule of thumb, but a fairly accurate one as a bare minimum for full load operation. We often ran our 25KW Magnate MK II on our 4000 that was rated for 52 hp... and when a compressor or large electric motor was trying to start, little blue was banging for hell to keep that turd spinning...

If you're just running a welder you'll obviously get away with quite a bit less tractor... but if you're going to hook it to the house with 100 amps of resistance heat you better have lots of guts in front of it.

Rod

25KW/.746/.85% =39.5HP shaft HP to operate the 25KW generator at full rated load.

I'm another one that tried a welder on a generac pto unit and it has an electronic voltage regulator and it got fried real quick. I'll never run another welder with one. Best get a welder and use it for a generator.