PTO Generator Wet Stack?

[avc8130]

Are there any concerns with wet-stacking?

If the tractor is singing along at ~2550 rpm to maintain 540rpm at the PTO to maintain 60hz...this would be a BAD situation on a standalone diesel genset unless the generator is loaded at least 40% of capacity.

Is this "problem" non-existent on the tractor?

ac

 

[leonz]

Are there any concerns with wet-stacking?

If the tractor is singing along at ~2550 rpm to maintain 540rpm at the PTO to maintain 60hz...this would be a BAD situation on a standalone diesel genset unless the generator is loaded at least 40% of capacity.

Is this "problem" non-existent on the tractor?

ac

You have a load sensing generator?

As long as the tractor has coolant, engine oil,
fuel and an intact V belt for the water pump it
will run until it is run out of fuel or the squirrels
in the neigborhood steal it for a joy ride and crash it.

 

[avc8130]

You have a load sensing generator?

As long as the tractor has coolant, engine oil,
fuel and an intact V belt for the water pump it
will run until it is run out of fuel or the squirrels
in the neigborhood steal it for a joy ride and crash it.

So this:
Generator Discourse: Wet Stacking: What is it and why is it bad?
is not an issue?

ac

 

[radioman]

I think you just answered your own question. if a tractor NEEDS to be ~2550 rpm to maintain 540 rpm at the PTO then its fine for the tractor. For the standalone genny - I am sure its designed differently. Just like MY BX tractor. It needs to be at high RPMS to be at rated pto that is considered screaming to others who are used to larger engines that purrs at low rpms.

 

[simoutdoors]

If I understand the "wet stacking" issue correctly, the concern is engine deposits from repetitive cycles that don't load the engine and warm it to temperature. For a tractor mounted generator I would assume you use the tractor for other task. During those work cycles the engine should warm sufficiently to remove any deposits.

 

[avc8130]

If I understand the "wet stacking" issue correctly, the concern is engine deposits from repetitive cycles that don't load the engine and warm it to temperature. For a tractor mounted generator I would assume you use the tractor for other task. During those work cycles the engine should warm sufficiently to remove any deposits.

Sort of. The main concern is operating the engine at a high rpm (2550 in this case) to get the required 60hz, WITHOUT a load. Generally speaking, there will be very little load on the engine unless the generator is producing more than 40% of its rated output. For a 30hp PTO, that would be a 15kw generator with a 6kw load. This would generally only be the case when well pumps, fridges, and other large loads are actually DRAWING power.

ac

 

[CNC Dan]

i think the generators the article refers to are air cooled.
Your tractor likly has a thermostat that controls the engine temp.

 

[aczlan]

i think the generators the article refers to are air cooled.
Your tractor likly has a thermostat that controls the engine temp.

Actually, this is less of a problem with aircooled diesels as they run hotter.
IMO, if you are using it as a tractor regularly, this shouldn't be an issue. It more of an issue when gensets sit (a lot), don't get fully warmed up in testing and then are lightly loaded.

Aaron Z

 

[zzvyb6]

I hook up my 50kw Winpower just to run a 110v hedge trimmer out in front. Its been fine for 20 years. No I'm not worried.

Here is a sample Owners manual for these jobs. Note the comments about split-phase motors and starting current.

 

[avc8130]

It's not about a problem on the GENERATOR side, it's about whether it can damage the tractor engine.

Hooking up a 15kw pto genset, and running the tractor for 10 straight days during a power outage, only drawing a few kw.

That is my concern.

ac

 

[avc8130]

Do typical tractors have speed governors?

I'm not sure if my L39 does. If I set the hand throttle to a certain position and drive up a hill, the engine RPM will drop as the load on the motor increases.

This would be BAD if it was an electrical load as the frequency would drift.

ac

 

[SPYDERLK]

Do typical tractors have speed governors?

I'm not sure if my L39 does. If I set the hand throttle to a certain position and drive up a hill, the engine RPM will drop as the load on the motor increases.

This would be BAD if it was an electrical load as the frequency would drift.

ac

Yes, theres a governor. If the load is too high you can overcome it. The engine speed stability is best at rated pto rpm. Try your experiment a gear lower and at a higher set rpm.
larry

 

[jgayman]

I think most are getting off topic. It seems the issue is not the generator and not running your tractor at 2500 RPM for extended periods but more generally running the diesel for extended periods with little or no load.

I'm having the same questions quite frankly. I just purchased my JD 2720 in July and its primary duty is snow removal - having replaced my old '54 Ford NAA. So I have about 7 hours on the engine so far by just putting around the property, pulling a small trailer, doing a little gravel grading with a rear blade and just trying to run the engine once in a while. I have not done anything to put any kind of load on the engine. I'm not even sure how I would go about it. Am I harming the engine? Should I attach a chain to my car and drag it around the yard? Should I try to pull some 100 year old trees out of the ground? Would that even put a "load" on my engine? :confused3:

When I bought a diesel powered tractor I never though I would be worrying about how to load the engine.

 

[dex3361]

Your tractor has a governor and would do well running a PTO genny up to the power available on the PTO.

 

[RickB]

To prevent wet stacking, do whatever is necessary to keep the engine temp up in or near the operating range. Cover part of the radiator, whatever. If the temp is up, it won't wet stack, period.

 

[avc8130]

I think most are getting off topic. It seems the issue is not the generator and not running your tractor at 2500 RPM for extended periods but more generally running the diesel for extended periods with little or no load.

I'm having the same questions quite frankly. I just purchased my JD 2720 in July and its primary duty is snow removal - having replaced my old '54 Ford NAA. So I have about 7 hours on the engine so far by just putting around the property, pulling a small trailer, doing a little gravel grading with a rear blade and just trying to run the engine once in a while. I have not done anything to put any kind of load on the engine. I'm not even sure how I would go about it. Am I harming the engine? Should I attach a chain to my car and drag it around the yard? Should I try to pull some 100 year old trees out of the ground? Would that even put a "load" on my engine? :confused3:

When I bought a diesel powered tractor I never though I would be worrying about how to load the engine.

Simply moving the tractor around is probably enough load.

It is very hard for most to visualize and comprehend electrical induced loads. With the tractor running at 2550 to make 540 pto, and the generator just connected, the tractor is essentially "idling" at 2550 with no load.

Driving around puts the load of moving the tractor. Add in a few hills, and you easily have load.

ac

 

[avc8130]

Your tractor has a governor and would do well running a PTO genny up to the power available on the PTO.

I realized that after posting. I know I can't go up some of my hills with the brush hog running in the same gear I use on the flats. I'm probably out of the realm of the governor heading up my driveway, it's quite steep.

ac

 

[dex3361]

I realized that after posting. I know I can't go up some of my hills with the brush hog running in the same gear I use on the flats. I'm probably out of the realm of the governor heading up my driveway, it's quite steep.

ac

I agree. I have a L4400 and it holds right on 60hz when running the PTO generator. I also have a BX1500 with 10PTO HP and it holds 60hz as long as you dont exceed the ability of the engine.

 

[XSKIER]

AC,

Here is your simple solution:
Install a 20 cell bank of 12VDC marine batteries. Then install an inverter to get 240VAC. Next place a rectifier on your PTO gen set to output 240VDC. Now install a switch that is triggered by a voltage drop in the battery bank. It should start and stop the Kubota at 2550 rpms while under load. That way your tractor would never spend one second "un-loaded" therefore no chance to "wet-stack". The system would operate just like your air compressor, ensuring a steady flow of power with a steady "load" on the supply unit.

 

[daybreak1998]

Howdy,
Diesel engine wet-stacking =
When a diesel engine runs at a higher rpm with out any load on it. It can have a tendancy to wet-stack after a long time in this condition. A diesel generator operating only has the possiblilty for a load through electrical load. A diesel tractor operating a pto generator, and then driving down the driveway, up hills, down hills, different gears etc... does not have the problem with wet-stacking. In other words, every now and then, you want to hear the diesel growl (load(extra black smoke)) coming out the exhaust. Start your tractor out in the highest gear you have from a dead stop... that is a load. Now, can a tractor wet stack - YES, fill it full, and let it sit there running whatever rpm you need to run 540pto speed, and lest it run out of fuel 4-5 times with no load. You might get it to wet stack. maybe...

All generators =
all generators should be frequently tested and loaded. Some of the easiest home style loads are those oil filled electric heaters. 2x1500w Oil filled heaters plugged in and turned on high gives a nice 3000w load. Add on a hair dryer, a air compressor, a 1500watt work light.

All generators should be tested longer then 5 minutes. When you do test and load a generator, you should run the generator long enough to throughly heat the unit, and oil. The oil with actually release water vapor. That is the reason to run it long enough to work the unit. That is the reason all the built in auto test last like 30 minutes each month.