3PT Generator Question

[TheGreyRider]

I have been looking at possibly buying a 3pt generator instead of using my gas powered in cases of lost power, i figure i need the tractor to haul the genny from the barn to the house anyway, why not just get a 3pt.

Question one is what RPM does the tractor have to run at to work? Does it matter?

Also does anyone have experience with them? Are they worth purchasing?

 

[windy acers]

Look at northern tool, you need 2 hp per 1000kw 10kw =20hp.3600 rpm is most common 1800rpm is availible at more cost but is the better set up.it is not wise to use the higher speeds of a 2 or 3 speed pto to keep the engine rpm"s lower on a 3600 rpm unit. 3600rpm is almost full throdale for most tractors.

 

[rambler]

I've no experience, but have heard what Windy says from many.

Tractor should run right at proper speed for a real 560 rpm pto speed - typically marked on the tractor RPM gauge or listed in the manual. I believe it is important to be pretty accurate here, to keep the 60 cycles correct.

--->Paul

 

[Deano]

We had a hurricane here last August. Needed my generator for 5 days. Did not run it at night, but ran it most of the day. While the generator was running, I was out with the thumb on the backhoe cleaning up trees that fell on my fences. I am glad I had use of the tractor while the wife and daughter were in the house with power.
That is just my situation. You may feel otherwise. Good luck with your decision!

 

[PHILIP8N]

PTO generators are set up for 540 rpm input, so you have to run your engine at rated PTO speed. Most PTO generators have a frequency meter so you can dial in your 60 hertz. Philip.

 

[nybirdman]

I have a Tiger Power 10K PTO Gen -set,just had to use it Jan.13-14 due to a ice storm and loss of power.Ran a total of 14 hrs and used 15 gallons of fuel on a L4240 Kubota(44hp).As stated need to run at 60HZ,which on mine is about 520 rpm pto speed.Worked very well and ran my whole house and garage.
Lots of reading here on stationary vs.Pto.I like my choice..I know my tractor will start and that I have enough fuel to run at extended outages.It takes only minutes to disconnect if I have other uses for the tractor.

 

[zoltanthegypsy]

Question based on total ignorance: does anyone make a 3-pt inverter generator - so it isn't so dependent on PTO RPM's?

It would probably be a needless complication and expense, but I'm curious.

Z.

 

[devildog1]

I have been looking at possibly buying a 3pt generator instead of using my gas powered in cases of lost power, i figure i need the tractor to haul the genny from the barn to the house anyway, why not just get a 3pt.

Question one is what RPM does the tractor have to run at to work? Does it matter?

Also does anyone have experience with them? Are they worth purchasing?

I guess it would depend if you only had one tractor and needed it for other storm related tasks during an power outage. I have 2 Honda generators and depending on what and how long I intend to run them will determine what one to use. Also remember the fuel required to run a large stand alone generator. My neighbor who operates a dairy farm has a huge PTO generator which he uses to keep the milk and barn equipment along with his house up and running. But in all fairness he has many tractors and the one I see operating the PTO Generator is usually a large IH 1066. Now he has other tractors to feed round hay bails and or keep drives clean so 18 wheelers can pick up milk. Just giving you different options, good luck.
DevilDog

 

[zzvyb6]

Yes you need to run the tractor so that the input pto is running at the generator's rated input rpm. Doesn't even have to be a tractor. I can run my 50KW Winpower off of my lawnmower for which I made a 540 pto output stub shaft.

No I don't need 100 hp to run my 50 kw generator (actually its an alternator). My tractor is 35 hp and my lawn mower was 22 hp when it was new. But I have never needed an equivalent amount of power from either motor for the house and barn, so it runs and performs its job just fine. I've NEVER hit the governor on either motor so it loafs along 100% of the time its being used.

No you don't need to run it full time. You run it long enough to get the house heated up or cooled, get water pressure up, catch some TV news, cook some dinner, or charge a phone, flashlight, computer, or weld something. Then you shut it down to use the tractor for something else if you need to. I don't understand why people feel the need to have their alternators running 24/7. In the worst of weather (hot or cold), mine is used for and hour or so and is off for several hours before its time to restart it.

 

[rbargeron]

Question based on total ignorance: does anyone make a 3-pt inverter generator - so it isn't so dependent on PTO RPM's? It would probably be a needless complication and expense, but I'm curious. Z.

As I understand inverter performance, they regulate output voltage AND frequency independent of the prime mover's rpm. They raise their engine's rpm when the total power being used requires it. It's that engine-speed-regulating function that would be difficult to connect to the tractor's engine so that it would be accurate and "play nice" with the rest of the inverter.

The simplest setup for running a generator with a tractor is to set the engine rpm to maintain a constant 60 hz generator output. Mine floats around with load a bit - maybe 59.5 to 60.5 - all the loads seem happy. I use a couple of these plug-in meters, one out by the tractor, the other in the house.

Another point I've noticed - a tractor's 2-speed pto can run a generator on the higher speed (lower engine rpm) but only if the tractor is big enough so changes in load don't affect it much. My 60 hp can loaf at 1700 rpm but but the 35 hp has to use the lower pto speed (engine at 2450 rpm) to be stable under changing load.

 

[zoltanthegypsy]

As I understand inverter performance, they regulate output voltage AND frequency independent of the prime mover's rpm. They raise their engine's rpm when the total power being used requires it. It's that engine-speed-regulating function that would be difficult to connect to the tractor's engine so that it would be accurate and "play nice" with the rest of the inverter....

Good point. Since the tractor's revs would have to stay up at all times, the small advantage of not having to maintain _exact_ revs wouldn't amount to much of an improvement.

Thanks for the thoughtful reply.

Z.

 

[RickB]

Another point I've noticed - a tractor's 2-speed pto can run a generator on the higher speed (lower engine rpm) but only if the tractor is big enough so changes in load don't affect it much. My 60 hp can loaf at 1700 rpm but but the 35 hp has to use the lower pto speed (engine at 2450 rpm) to be stable under changing load.

My Case 885 with 2 speed PTO can run the whole house easily in PTO high which is 540 PTO RPM @ 1100 ERPM and it burns about 1/2 GPH of fuel. Unless during a midsummer outage we decide to run the central air conditioning. Then I need to run it in the normal PTO setting of 540 PTO RPM @ 1800 ERPM.

 

[displacedPA]

Could I run my PTO of my B2320 at the high setting which is 960 then lower the rpms on the tractor until i reach the 540 range for the pto gen. i would not use it for a large duty cycle just on and off to run the well ect. ?

 

[psdx]

Could I run my PTO of my B2320 at the high setting which is 960 then lower the rpms on the tractor until i reach the 540 range for the pto gen. i would not use it for a large duty cycle just on and off to run the well ect. ?

Depends... The generator gearbox is meant to supply power at the proper frequency with the input to the gearbox spinning at 540 rpm. So first, you need to have a way (either built into the generator or with a separate test set) to validate the generator output frequency (unless maybe your tractor's tach has a mark for getting 540 with the selector set at 960).. Second, this assumes that your tractor generates enough hp at the lower engine rpm to keep the generator spinning at a constant speed when the load varies. You can figure about 2hp per kw of generated power. You can find your engine's rated hp at whatever speed it's going when you've throttled it back by looking on the web for Kubota engine specs and getting it from the hp curve chart.

...last point, your well pump is almost certainly the one item in your home with the largest electrical load at start. A well pump can draw as much as 6 kw to start. Your PTO power at full rated speed is easily capable of generating sufficient power to start your well. But if you want to seriously consider this, please post your well pump's hp rating and manufacturer name, e output rating of your PTO generator, and what the engine rpm on your tractor would be to spin the PTO at 540, when your speed selector is set at 960.

 

[PHILIP8N]

Could I run my PTO of my B2320 at the high setting which is 960 then lower the rpms on the tractor until i reach the 540 range for the pto gen. i would not use it for a large duty cycle just on and off to run the well ect. ?

Yes, As long as the tractor engine can keep up with the electrical demand and not loose rpm and begin to lug. Mind the in-rush load of the well pump. Philip.

 

[displacedPA]

yes i will have to investigate that perhaps I would run at full rated rpm to run the well pump. Then run at the lower rpm for everything else. thanks

 

[PHILIP8N]

Personally, I would just run at high engine speed and not worry about it. What are your engine speeds when running at 540 pto rpm? What are you saving? Fuel, not so much. Engine wear, some. But, a well maintained Kubota engine should last around 8000 hours before rebuild. Can you accumulate that in your lifetime? I have a 10kw gasoline portable backup generator I use to run our house in power outages. I have had it since 2000 (bought it on a deal after the electronic world ended as we knew it on Dec 31, 1999.). It runs 3600 rpm, I keep it well maintained, excersise it monthly, and it has just over 200 hours on it. What tractor do you have? We should be able to find an engine data sheet that will show you horsepower output and fuel consumption at different rpm's. That would help your decision. Philip.

 

[displacedPA]

I have a B2320,

I just looked at some engine data sheet and your right im not saving that much... and in reality your right I keep up on my maint. so what am I even worring about... I also do not need the gen. all the time so the tractor will not be run that much either.

 

[PHILIP8N]

I have a B2320,

I just looked at some engine data sheet and your right im not saving that much... and in reality your right I keep up on my maint. so what am I even worring about... I also do not need the gen. all the time so the tractor will not be run that much either.

Are these the same engine data sheets you found? You still need to know engine rpm at your two 540 pto output speeds to use the curves. Philip.

 

[chiefchicken]

I picked up a 10kw from IMD (a TBN advertiser) about 2 years ago. Excellent quality, and all in all it was the best price around. Nothing "made in China", the generator head and gearbox are made extremely well. They sold me an entire package that included generator, gearbox, 3 point hitch frame, and PTO shaft.

IMD - PTO Generators

After Hurricane Irene, we were out of power for 8 days, and I ran the generator approximately 5 hours per day. No complaints at all. On my BX2350, engine rpms are at 3050 for proper generator output.

For the first 4 days, there was NOTHING around us that was opened. Having a diesel tractor spinning my generator was great because all I had to do for fuel was transfer a few gallons each day from my heating oil tank (through a filter, of course).

When I wasn't providing power, the generator just stayed on the back of the tractor and provided a nice counterweight as I cleaned up the yard.

You have to weigh out what makes the most sense for you. If you are going to need to use the tractor (loader, etc) and the generator at the same time, you may want to consider a stand alone unit.

For me, the benefit of having the generator powered by my tractor work well. Your mileage may vary!