PTO speed question

   / PTO speed question #1  

smfcpacfp

Veteran Member
Joined
Nov 21, 2007
Messages
1,346
Location
Sands Township, Marquette Co, Michigan
Tractor
Kubota B3030HSDC
Ok guys be patient because I have only owned my B3030 for about 3 weeks and operated it five times snow blowing, but there is something that isn't crystal clear in the operating manual.

When using a PTO set the hand throttle lever control to the "PTO" setting on the tachometer. To control the tractor running speed, chose the appropriate L M or H gear and use varying pressure on the speed control pedal. When not operating the PTO, I would guess that you don't need to run the engine speed at that that high of an RPM, even if you are driving the tractor. Is this correct?
 
   / PTO speed question #2  
That is correct. I don't even run mine up to the PTO speed when using implements now because I only have about 12 hours on my B3030, I try to keep my RPM's varied from 1,400 to 2,100 or so. There are lots of opinions on break-in but I am trying to go easy for the first 50.
 
   / PTO speed question #3  
As a sweeping generalization;
PTO speed is 540 (or 1,000 - maybe some other special set speed) at the indicated rev for maximum power (force times speed).
Only SOME PTO implements/attachments are really speed sensitive, e.g. generators. Things like tillers and some sprayers may have a maximum PTO speed, but lower speeds are unlikely to harm them. They may be less efficient at say 450 or 400, but won't just quit and turn belly up.

You didn't ask and it may not apply to your particular tractor, but in many cases it is practical to run 540 RPM implements off the 1,000 RPM gear with the engine running at 54% (or so) of the recommended engine RPM.
 
   / PTO speed question #4  
There will be plenty of times when you will be running a PTO impliment, say.... even your snowblower, when you may find it more enjoyable to run it at less than "PTO speed". You may find it blows snow just fine at 3 - 400 rpms less , and is quieter in the cab at that RPM. Or, if you are running a brush chipper on just smaller limbs, you may find that the chipper operates just fine @ 1800rpm. Like anything else, once you've got more hours under you belt........ you'll make adjustments in your operating habits that work better for you.
 
   / PTO speed question
  • Thread Starter
#5  
Thanks for the useful information, guys. I have been running with the snowblower at less than the PTO speed. It is definitely quieter, and we haven't more than 9" of low moisture content snow at any one time, and it just seemed so effortless for the tractor.
 
   / PTO speed question #6  
Another question - isn't it harder on the tractor and more likely to bog the engine down when running an attachment at less than 540 PTO RPM? For instance a tiller, brush hog, chipper all could run just fine at 400 - 450 PTO RPM right up until that one branch or root gets caught up and then you are lugging and bogging the engine. Also at those speeds you are way more likely to lug the engine to the point of shut-down because you are not running at peak power. And all this can happen very quickly and I would assume that this is not good for the tractor? Right? I guess it would come down to the risk factor. Are you willing to take the risk of possibly damaging the tractor to save a few RPM that the diesel engine was designed to run at to begin with. I am not saying that it will do damage the first or even second time, but we all say that bogging and lugging the engine is not good at all and I would think that by running an implement with less RPM than designed to that you are putting the tractor at risk. Thoughts??
 
   / PTO speed question #7  
I do understand that a snowblower on the other hand is way less likely to bind up or bog down unexpenctantly. I was speaking more for tillers, brush hogs, chippers, etc.....
 
   / PTO speed question #8  
I certainly understand your point, but in reality, this could happen at any power setting if you hit an unexpected object with a tiller or brush hog, and the result would be the same. I run enough power so the implement operation does not impact the engine RPM's. As an example, when tilling, lowering the tiller to the lowest point does not cause the engine to bog down when being operated. Certainly, I could hit a root or rock which could cause bogging, but the implements usually have a slip clutch or shear pin to prevent damaging the tractor in the event you hit a solid object. Since I don't run anything that is speed sensitive like a generator, I'm not all that concerned with actual PTO speed. Also, knowing the ground you are working is clear of things like stumps and discarded wire or fencing is always a good idea. Stan

Adam23 said:
Another question - isn't it harder on the tractor and more likely to bog the engine down when running an attachment at less than 540 PTO RPM? For instance a tiller, brush hog, chipper all could run just fine at 400 - 450 PTO RPM right up until that one branch or root gets caught up and then you are lugging and bogging the engine. Also at those speeds you are way more likely to lug the engine to the point of shut-down because you are not running at peak power. And all this can happen very quickly and I would assume that this is not good for the tractor? Right? I guess it would come down to the risk factor. Are you willing to take the risk of possibly damaging the tractor to save a few RPM that the diesel engine was designed to run at to begin with. I am not saying that it will do damage the first or even second time, but we all say that bogging and lugging the engine is not good at all and I would think that by running an implement with less RPM than designed to that you are putting the tractor at risk. Thoughts??
 
   / PTO speed question #9  
It won't hurt the engine to bog. It can only produce a certain amount of torque regardless of the RPM. The torque is limited by the amount of fuel introduced by the injectors. Once the RPM starts to drop even slightly, the governor opens the fuel flow to max where it stays until the engine stops. The greater chance for damage is a sudden stop from a high RPM. The sudden stop such as jamming a rock in a rotating device that doesn't slip or shear a pin will produce a shock load. I use generally use the slowest engine speed that gets the job done. If the grass is short and drought stricken, I mow at 2,500 RPM. If high and thick, 3,300. If you drop the revs back even a little, you'll see the fuel consumption drop drastically.
 
   / PTO speed question #10  
I have a GL4630gstc and have just hit 50 hours. With front mount blower i have been running engine at 1800 to 2000 and blower works fine. Also used these speeds for 3pt log splitter. My father inlaw is old school and says don't rev engine if not required.
 

Attachments

  • gl4630.JPG
    gl4630.JPG
    240.8 KB · Views: 182
 
Top