fuel usage pto generator

[d17man]

hi all, I bought an older 15kw pto generator for the purpose of powering the house during storms/power outages. my question is what tractor would be most economical to run it.
option one: my allis d17 diesel. my concern with it is this tractor might be getting a little tired(runs 35-40psi oil pressure when warmed up) and during a long power outage may have to check/add oil often. the other downfall to using the d17 is it is hard starting in the winter.

option two: our john deere 2550. this is probably the best choice as its a good cold starter, easy on fuel and fairly quiet. the problem is this is our loader tractor and if there is a snow storm we need it for plowing and cant really have it tied up on a generator.

the last option is our international 1086, yea a bit overkill but I was wondering if we put a 1000 rpm to 540 rpm adapter on it if we could power the generator at a lower engine speed and use less or the same amount of fuel as the two smaller tractors.
your advice and opinions are appreciated, thanks

 

[Bob Bancroft]

Option 4.
Buy my AC "C" ! It used to be my yard/auger/PTO tractor, but I don't need it anymore.
I have a 25/15 KW alternator I have only ever run once overnight to power the house. The C ran it easily. It was quiet as PTO speed is a leisurely 1350 engine RPM. Of course it will start anytime. And if it did run out of fuel, no big deal.

 

[Anonymous-0]

I think you are on the right track with the 1086 on the 1000 rpm shaft. I use a 9000 Ford on irrigation pumps, tractor runs less than half throttle. We think it saves fuel and doesn't tie up other tractors that we use more.

 

[VicS]

I would try the 1086 on the 1000 pto. But my neighbor tried that on a 35 kw gen and we couldn't get the mix-mill to start, have to have the feed blower running first. It would not start the grinder. The clutch was slipping in the pto. We changed it to the 540 shaft and revved the engine up. It pulled it easily, and didn't slip.

 

[jm.]

This is a hot topic on here and what I am about to say is just one mans opinion BUT I have 28 years experience selling, servicing generators. The pto operated generator is not a good choice for house operation. Here is what happens you hook up you tractor/generator set the tractor rpm to get the desired output. Now ten minutes latter the load changes because the well , hot water heater or what ever kicks on then you burning out your tv or something else due to low voltage. I see folks power a milk barn or things for short times with the pto generators with no trouble but long term for the house can be problems. I would think about it before I bought the pto adapter but the larger tractor with the adapter would be my choice for your question but thinking you may want to rethink the complete thing. And yes there will be folks answer in a few that say they have never experienced any problems. About like the ethanol/ gas thing on here some have problems so do not.

 

[JDemaris]

I powered my complete house many, many times with a 15KW PTO generator before I switched to solar electric. Never had any issues with burning out anything. Not even when my kid revved the engine way too high and the light bulbs in our house got VERY bright. No TVs burned out, not did anything else.

Picking the most fuel efficient will be choosing the smallest tractor that can power it, assume they are all diesels. When running an entire house - much of the time the tractor will hardly be be working hard and will lug down a bit when a power surge comes up. Any tractor is most efficient when run at the peak of its torque curve. That means that much of the time that tractor is running it will only be using 5-10 horsepower. At max to make 15KW maybe 30 horse. The most efficient would be a tractor with a max of 30-35 PTO horsepower. Very easy to verify. Look at some Nebraska tests and how much fuel big tractors waste when run at low power levels.

 

[samn40]

We used our 6 cylinder 100 hp Massey 699 on the genny with the 1000rpm shaft. tractor revs were around 1150 to get 540 PTO and it run the complete farm and house. Any tractor with less power died away unless running on the 540 shaft at 1900 rpm on the engine. I am sure the 699 was the most efficient.
Sam

 

[wisbaker]

PTO not a good choice? Wonderful (the art of politics, think BS and say "wonderful") thought adjusting the throttle to keep the speed consistent was why we have governors on tractors? If we apply the same logic NO engine driven generator would be acceptable 'cause the rpms would change with the load.

 

[fixerupper]

The governor on that rotary Bosh pump on a 1086 isn't very active at lower speeds. 540 on the 540 shaft is at 1900 RPM's give or take and the governor will be responsive as it will ever be. The 1000 shaft run at 540 means the engine will be running maybe 950-1000 as an educated guess, maybe less. The governor's not much good in that RPM range. Jim

 

[JDemaris]

Here are a few gallons-per-hour figures at low power levels. No doubt the IH 1086 would be the worst. I'm figuring the most that 15KW is going to use is 30 horse. The biggest tractor will be the biggest dog at low power levels.

AC D17
12.2 horse @ 1.7 GPH
23.8 horse @ 2.1 GPH
28 horse @ 2.4 GPH
34.6 horse @ 2.6 GPH

IH 1086
30.6 horse @ 4.2 GPH

JD 2550
14.6 horse @ 2 GPH
29 horse @ 2.5 GPH

 

[RodinNS]

I'd be inclined to use the Allis. A whiff of ether will make it run...
Having a DT running at a fast idle is a recipe for slobber. Not a great thing for that engine.

Rod

 

[Tech 7]

What ever tractor you choose put Murphy Switches on it. One less thing to think about.

 

[Fordfarmer]

In the 30+ years we've had a PTO generator, the only time we've needed to run it more than a few hours at a time was when a tornado leveled a big part of the town and ruined miles of power lines. Ran it 4 or 5 days then. Only shut down to refuel.
If it was me, I'd plan on using either of the smaller tractors - whichever one isn't needed elsewhere. If the D17 won't start, use the JD until the D17 is warmed up, then switch. Maybe get the adapter as a 'just in case', but you're better off using the smaller tractors.

 

[Anonymous-0]

I agree with that. Some diesels can be run for long periods at low RPM but other's will slobber worse than a dozen St. Bernards and can actually get glazed up where they won't rev up. Cat 3200 series are an example of engines that shouldn't idle for long periods. I've seen an IH 966 that slobbered like a pig too from too much idling. The other problem you run into is the engine not getting to proper operating temperature. Not good for a diesel. That's why most diesel trucks have a hand throttle to speed them up so they warm up and stay warm. Diesels need to work and if the injection pump is working properly, it will act as a governor. Diesel gensets don't have special governors added that I know off. The throttle on a tractor might creep though.

 

[d17man]

Thank you for all the replys. I think the d17 will be our choice of tractors

 

[ss55]

I think 2 horsepower per kilowatt is the recommended engine size for most generaors. You might check with a manufacturer to see what size tractor they recommend for a unit like yours.

 

[Bret4207]

(quoted from post at 16:40:55 10/17/13) This is a hot topic on here and what I am about to say is just one mans opinion BUT I have 28 years experience selling, servicing generators. The pto operated generator is not a good choice for house operation. Here is what happens you hook up you tractor/generator set the tractor rpm to get the desired output. Now ten minutes latter the load changes because the well , hot water heater or what ever kicks on then you burning out your tv or something else due to low voltage. I see folks power a milk barn or things for short times with the pto generators with no trouble but long term for the house can be problems. I would think about it before I bought the pto adapter but the larger tractor with the adapter would be my choice for your question but thinking you may want to rethink the complete thing. And yes there will be folks answer in a few that say they have never experienced any problems. About like the ethanol/ gas thing on here some have problems so do not.

During our infamous Ice Storm of 98 we were without power for 15 days, much if it in sub zero temps. Some folks around me ran PTO gensets. What they found lines up with the post above. It's one thing to run the barn at milking or the well pump and freezers, it's another to run the TV, computer and other more delicate items. We also found out the gear boxes on a lot of PTO gens were just not up to 24/7 usage. No one ever thinks to service those gearboxes. Just FYI.

 

[RMinVa]

I use a Deutz Fahr Agrofarm 100 to run the same size generator. I sift to 1000 rpm pto and run engine at 1200 rpm to get 540 on the pto display.

I've listened to the tractor engine and watched the rpm's while my wife would turn on different appliances in the house and never saw a rpm change or heard the engine change tone at all. We use tv, laptop and desktop computers and have no problems. I also hooked a fluke 85 meter up while running to watch hertz and voltage and see no change to be concerned with.

Tractor engine is 4 cylinder w/turbo and has high pressure fuel rail. 96 hp. They deliver fuel according to load very well. Chisel plow it uses about 3.5 gph. Running that generator it uses about 1.2 gph. I run a wood splitter at 1200 engine rpms and can get 38 hours out of a 40 gal. tank of fuel when fuel light comes on. Never any diesel slobber at low rpms because of the fuel management system.

Other tractors I used with the generator was 574 IH, 2610 Long and Farmtrac 80. All were 540 only and they used 2-3 gph. So you might want to try the 1086. May use less fuel.

 

[JDemaris]

The difference is - self-contained fuel-powered gensets generally do not have adjustable throttles like farm tractors do. They are set to run at only only one governed speed to make the correct Hertz Cycle (if an AC rig and not DC inverter type). When a PTO generator is hooked to a farm tractor, it's easy to under or over rev it just by hitting the throttle. Happened here many times. Never hurt anything though. Just made the clock run fast and light bulbs extra bright.

 

[RodinNS]

One other thing... you should get a multimeter that has a frequency/hertz function in it. That way you can set the speed at 60 Hz and then you know it's running at the right speed. The Magnate MK II that I use will also make 60Hz at 250 Volts but that may not be the same for whatever gen you have... but that can be a pretty close guide if you don't have a meter with Hz function.

Rod

 

[VaTom]

Sounds like you"re set.

I can pull 17 Kw out of my PTO generator with my 25 hp compact tractor. Our house doesn"t need anywhere near that much so during an outage I use the 1000 PTO speed to greatly reduce the engine RPM and save 1/3 on fuel.

The meter on my generator is adequate for setting engine speed to give proper frequency for house electronics. Never any problem.

When I need more current, like for portable welding, 540 PTO speed works well. This is a 25 Kw generator, doesn"t mind at all a small power plant. Thought I"d power from a Cat hydraulics, bought the hydraulic motor, but realized I have no need for that much current. Much better to fuel a compact tractor.

 

[Fordfarmer]

2 h.p. per kw is roughly the minimum needed when the generator is at full load.

 

[mkirsch]

Using the 1000 PTO on the generator did not work well for us.

Tractor was a 1066. Dad thought he could save some fuel by running on the 1000 PTO. At the time the tractor dynoed 180HP.

The problem was the governor could not react quickly enough to something like a silo unloader starting. It would overcompensate, then get to "bouncing" worse and worse until it eventually popped the main breaker on the generator.

Of course the generator was overloaded to begin with so that may have contributed to the issue.

 

[buickanddeere]

2HP per KW output is the rule of thumb for sizing. Actually takes approx 1.5HP to make 1KW.
Over sizing is to provide motor starting overload capacity . And to reduce engine wear from operating at max.

 

[buickanddeere]

Goes to show the difference between the modern ECM controlled common rail engine. And a worn out mechanical 1086 governor operating below it's rpm design range.