What RPM's do you run at when using PTO?

[Bob_Young]

Re: What RPM\'s do you run at when using PTO?

You members that run full PTO RPM on your implements and have a digital PTO RPM display; how do you handle it when the going gets tough and the PTO RPM drops? Assume you're already creeping at a snail's pace and you've got the reserve power to bring RPM back up. Do you just feed more throttle to it to hold the rated RPM? How much of this is too much? What's the limit? Does anyone have experience with this leading to equipment failure?

I've run into this blowing snow with a NH TV140 and have reason to believe it's a recipe for disaster. The TV140's turbocharged, so that may be a factor.
Bob

 

[JerryG]

Re: What RPM\'s do you run at when using PTO?

As long as RPMs don't go down low enough to lug the engine and the engine doesn't over heat, it is fine to give it more throttle.

 

[_RaT_]

Re: What RPM\'s do you run at when using PTO?

While I rarely run full PTO RPM, when I mow and I hear the engine load up, I just back off on the hydro pedal and I not only slow the feed rate down but take load off the engine by requiring less forward speed. As soon as it picks back up, I resume or modify my ground speed. It's all based on conditions. Wet, tall grass obviously requires more power which typically requires me to slow down.

 

[PineRidge]

Re: What RPM\'s do you run at when using PTO?

I'm with Rat as I don't fiddle with throttle when it's so easy to change ground speed with the hydro pedal. This is where hydros really shine. Once the RPM's come back to normal the cruise goes back on.

 

[AndyMA]

Re: What RPM\'s do you run at when using PTO?

</font><font color="blue" class="small">( You members that run full PTO RPM on your implements and have a digital PTO RPM display; how do you handle it when the going gets tough and the PTO RPM drops? Assume you're already creeping at a snail's pace and you've got the reserve power to bring RPM back up. Do you just feed more throttle to it to hold the rated RPM? How much of this is too much? What's the limit? Does anyone have experience with this leading to equipment failure?

I've run into this blowing snow with a NH TV140 and have reason to believe it's a recipe for disaster. The TV140's turbocharged, so that may be a factor.
Bob )</font>

Bob I don't believe its a receipe for disaster at all. Especially on something as strong as a TV. On my turbocharged TN75, when the going gets tough the "torque reserve" kicks in and the engine just lugs harder to maintain PTO speed. Tractor engines, especially Utility size and above are strong beasts designed to work under full load conditions day in and out. High end consumer grade compacts are also strong, but most of them aren't in the same league with a true utility or ag tractor when it comes to longevitity. In engieering school we spent quite a bit of time studing various forms of power generation (that was my speciality in school at least) and as I remember it most diesels are designed to run at what we are referrign to as PTO speed continously. In fact if you look at the technical spec sheets on the engines themselves, I believe you will fine it called High Idle Speed /forums/images/graemlins/confused.gif Makes you wonder just why they use the word Idle. I think you may find that the peak stresses (other than the rotational and linear friction components) are actually higher at lower rpm's on certain of the driveline components. I may be all wet, but thats how I see it.

BTW I only run rated PTO speed for all mowers and a few other implements. For mowers, it's all about "blade tip speed" -they are designed to run at a certain "blade tip speed". Snowblowers- rated PTO speed and let the governer do it's job. For most other implements I run at "what feels right" /forums/images/graemlins/cool.gif


Andy

 

[KiotiJohn]

Re: What RPM\'s do you run at when using PTO?

</font><font color="blue" class="small">( In fact if you look at the technical spec sheets on the engines themselves, I believe you will fine it called High Idle Speed Makes you wonder just why they use the word Idle. )</font>
I'm glad to see someone else comment on this as I HATE that term. To me idle is the lowest speed the engine can run, not just that it hits a certain speed and is held there. I'm sure that's what they mean, that it's held in place at a high speed, but it just grates on me when I hear that term used for anything but "low idle." LOL
John

 

[ksmmoto]

Re: What RPM\'s do you run at when using PTO?

I seen lots of local farmers run both gas and diesel tractors on irrigation pumps around the clock. All running at pto speed night and day.

ksmmoto

 

[jinman]

Re: What RPM\'s do you run at when using PTO?

</font><font color="blue" class="small">( I'm glad to see someone else comment on this as I HATE that term. To me idle is the lowest speed the engine can run, not just that it hits a certain speed and is held there. I'm sure that's what they mean, that it's held in place at a high speed, but it just grates on me when I hear that term used for anything but "low idle." )</font>

The high/low idle terms make me uncomfortable too, but I think the reference to the rpm of the engine is the "high/low" portion of the term and "idle" represents that the engine is under no-load conditions. Most of us set the engine speed under no-load conditions and then proceed to do work while letting the governor maintain the rpm. I have as hard a time as you with that terminology, but I can see where it sorta makes sense. /forums/images/graemlins/crazy.gif /forums/images/graemlins/smile.gif