Generator PTO vs Gas Engine Generator

[Kioti Tom]

hi,

i'm thinking of a 25kw PTO generator for my 105hp JD. it wouldn't be used often but there more for long term issues down the road if need be. i don't want to tap into our propane tank because i want that fuel available elsewhere and i'ld probably burn 2 gallons of propane/hr. just how many gallons of diesel per hour would my tractor burn at 540rpm? i've got the 4 cylinder diesel engine.

thanks,

First, :welcome: to TBN. You have to consider the rpm you have to run your tractor to get 540 rpm on the PTO. My Kioti
produces 540 PTO at 2600 rpm. That can use up the diesel. If you can work that out, then you will have an approximate
idea of fuel useage...
Good luck
Tom

 

[aczlan]

Do you have the 1000 RPM PTO option (aka "e-pto"?) If you have a way to spin your PTO faster than normal (such as a 1000RPM mode) you can probably save a little on fuel that way
The Nebraska tractor tests lists that tractor as using 1.43 to 5.75 gallons per hour depending on the load (Source: http://tractortestlab.unl.edu/deere/5105m.pdf) and most 25KW gensets want 50HP. If the generator is using 50HP, the tractor will use ~4 gallons per hour. If you are lightly loading it, you will probably still use at least 2 gallons per hour.

Aaron Z

 

[Soundguy]

fuel usage will be based on electrical load. ( hp used )

hi,

i'm thinking of a 25kw PTO generator for my 105hp JD. it wouldn't be used often but there more for long term issues down the road if need be. i don't want to tap into our propane tank because i want that fuel available elsewhere and i'ld probably burn 2 gallons of propane/hr. just how many gallons of diesel per hour would my tractor burn at 540rpm? i've got the 4 cylinder diesel engine.

thanks,

mike

 

[msch2112]

thanks for the replies guys. yes, the PTO has a 540E and standard 540. according to the manual, in 540 mode i reach 1000rpm PTO at 2100 rpm engine speed. i am just guessing right now i'ld use 50% of the load for a 25kw.

i was just thinking that not buying another motor in a generator is one less repair/maintenance task for me! i'm not a genius in the electrical department at all and kw, v, a, and watts is killing me.

mike

 

[leonz]

Check the Nebraska tractor tests for your mules fuel consumption
at the throttle high idle setting for 540 rpm.

 

[Soundguy]

i also prefer having 1 less engine to feed. plus i trust my tractor engine alot more than the lawnmower eng on most small gennies..

thanks for the replies guys. yes, the PTO has a 540E and standard 540. according to the manual, in 540 mode i reach 1000rpm PTO at 2100 rpm engine speed. i am just guessing right now i'ld use 50% of the load for a 25kw.

i was just thinking that not buying another motor in a generator is one less repair/maintenance task for me! i'm not a genius in the electrical department at all and kw, v, a, and watts is killing me.

mike

 

[msch2112]

Do you have the 1000 RPM PTO option (aka "e-pto"?) If you have a way to spin your PTO faster than normal (such as a 1000RPM mode) you can probably save a little on fuel that way
The Nebraska tractor tests lists that tractor as using 1.43 to 5.75 gallons per hour depending on the load (Source: http://tractortestlab.unl.edu/deere/5105m.pdf) and most 25KW gensets want 50HP. If the generator is using 50HP, the tractor will use ~4 gallons per hour. If you are lightly loading it, you will probably still use at least 2 gallons per hour.

Aaron Z

great site you referenced! i'm a little shocked to see i use that much fuel on the PTO alone. guess i hadn't paid attention. since i'm using 5.75gal/hr in at 2100rpm at 1000, i'm not sure this is as economical i thought it would be. not sure running the generator at 50% would reduce fuel consumption that much.

thanks again!

mike

ps. i can't believe all the info out there on tractorbynet. looks like i've been missing alot.

 

[schmism]

since i'm using 5.75gal/hr in at 2100rpm at 1000, i'm not sure this is as economical i thought it would be.
.

as your over driving that genhead with about twice the hp as needed... i wouldn't be surprised if your in the 4gal per hr.

a standalone 25Kw genset runs at roughly 2.2 gal diesel an hr or 3.3 gal propane an hr (on ~50hp engines)

 

[daybreak1998]

great site you referenced! i'm a little shocked to see i use that much fuel on the PTO alone. guess i hadn't paid attention. since i'm using 5.75gal/hr in at 2100rpm at 1000, i'm not sure this is as economical i thought it would be. not sure running the generator at 50% would reduce fuel consumption that much.

thanks again!

mike

ps. i can't believe all the info out there on tractorbynet. looks like i've been missing alot.

Howdy,
Do not believe any of that information on that site. It really has no bearing on running a PTO generator. That's like saying running a hay tedder at 540, would use the same fuel has running a batwing bushhog at 540.

Which JD is it?
6430premium (listed at 135hp or true 109 pto hp) here with the 540e running a tiger power 30kw generator with a load af about 17kw, I was burning approx 1.4g/hr by looking at the computer panel for fuel usage. The actual engine rpm is around 1610rpm with of course the pto shaft at 540rpm
Like anything, I am not trying to run the generator at 100% capacity either. If you go with a 25kw generator, I am sure it will run everything you have.

Larger PTO generator will have 4 pole heads = a good thing = the internals then spin at 1800rpm = which translates into less gearing from the shaft = quieter performance
smaller PTO generators will have 2 pole heads which need to sping along at 3600rpm = more gearing = more noise from gears and internals spinning fast = longevity compromised

 

[aczlan]

Howdy,
Do not believe any of that information on that site. It really has no bearing on running a PTO generator. That's like saying running a hay tedder at 540, would use the same fuel has running a batwing bushhog at 540.

Did you read the PDF I linked? It has a table with x PTO HP used = y gallons of fuel used per hour.
Of course you will use less fuel running a tedder than you would running a bush hog, but that tractor will use ~1.7 gallons of fuel per hour just to spin the engine at 2200 RPM.

His profile lists a JD 5105m, so that is what I looked up on the Nebraska Tractor tests which are very well regarded at measuring the actual output of a tractor.

Aaron Z

 

[Soundguy]

Did you read the PDF I linked? It has a table with x PTO HP used = y gallons of fuel used per hour.
Of course you will use less fuel running a tedder than you would running a bush hog, but that tractor will use ~1.7 gallons of fuel per hour just to spin the engine at 2200 RPM.

No.. obviously he didn't.. or didn't understand what he read.

load determines fuel usage...

 

[daybreak1998]

No.. obviously he didn't.. or didn't understand what he read.

load determines fuel usage...

Howdy,
The problem is I did read it.
The answer is I have real world results, but with a different tractor. I saw the JD 5105m listed as his tractor. He said he has a 105hp tractor. To me that is then really into the 6000 series tractor. But with all the naming changes with Deere tractors, I dunno.

True.. a 25kw pto generator running off a 48hp tractor totally loaded amp load to 25kw prime. Yes, it will swallow some diesel. Tractor data shows his 5105m can have the 540e mode. I am not sure if he ordered that. (yes, lots of folks flip the shaft and run 1000 pto speed then with a converter (21-spline to 6-spline))

 

[Soundguy]

no matter HOW you do it. load determins fuel usage.. period...

 

[Mark Petrowicz]

Mike,
fuel consumption would be the same if you were running the tractor at 2500 rpm with or with out the generator i imagine as you will need th pto up to a certian speed to generate the power. to generator 25kw u will need a very large coiled motor . what were you lookin at for voltage and amperage? you might want to generate 3 phase power say 480v and step it down with a transformer if you need a lot of power. always consult an electrical engineer before you go into anything like this prior to putting down any green backs.
Good luck
Mark

 

[davel8257]

A theoretical approach based upon the energy content of diesel fuel is interesting. Here's a link to a website that converts Kwh to gallons of diesel fuel: Convert kWh to gallon [U.S.] of diesel oil - Conversion of Measurement Units

If you plug in 10Khw, it comes up with .245 gallons (per hour). That's the theoretical maximum, no friction, no losses, 100% efficiency. If our cars could do that, we'd all be getting more than 100 MPG.

 

[aczlan]

Mike,
fuel consumption would be the same if you were running the tractor at 2500 rpm with or with out the generator i imagine as you will need th pto up to a certian speed to generate the power.

Not so. Take a look at page 3 of my link earlier.
From that page:
HP - RPM - Gal/hr
91.76 - 2100 - 5.71
68.65 - 2106 - 4.51
45.54 - 2093 - 3.35
22.88 - 2103 - 2.21
0.59 - 2107 - 1.15

So, 91HP used at 2100 engine RPM burned 5.71 gallons per hour while 22.8 HP used at 2103 engine RPM burned 2.21 gallons per hour and 0.59 HP used at 2107 engine RPM burned 1.15 gallons per hour.

Aaron Z

 

[Mark Petrowicz]

Aaron,
Thanks for the info.

 

[Soundguy]

Aaron,
Thanks for the info.

yep.. it's not the 'rpm' that uses the fuel.. it's the LOAD... load determins fuel. though you will get a practical 'floor' where you will have some minimum amount of fuel usage no matter what.. etc..

 

[msch2112]

Not so. Take a look at page 3 of my link earlier.
From that page:
HP - RPM - Gal/hr
91.76 - 2100 - 5.71
68.65 - 2106 - 4.51
45.54 - 2093 - 3.35
22.88 - 2103 - 2.21
0.59 - 2107 - 1.15

So, 91HP used at 2100 engine RPM burned 5.71 gallons per hour while 22.8 HP used at 2103 engine RPM burned 2.21 gallons per hour and 0.59 HP used at 2107 engine RPM burned 1.15 gallons per hour.

Aaron Z

i can't believe a 7rpm increase resulted in a 4.56gph reduction! guess it's the decrease in HP.

Mike

 

[aczlan]

i can't believe a 7rpm increase resulted in a 4.56gph reduction! guess it's the decrease in HP.

Yes, it is all about the HP used. Compare the numbers for 68.65 HP (2106 RPM, 4.51 GPH), 45.54 HP (2093 RPM, 3.35 GPH) and 22.88 HP (2103 RPM, 2.21 GPH)

Aaron Z