Live Vs independent PTO

[ericm979]

The only tractor I've operated has a live PTO. Some of the tractors in the 30-40hp class I'm contemplating have independent PTOs. Though I've not used it, it seems like it'd be convenient. Rather than stopping and clutching to start or stop the PTO you can just hit a button or move a lever, and you could do it while not on the seat for operating a chipper. Those of you with independent PTOs, how useful is it in practice? My PTO work is chipping and running a rotary cutter.

Independent PTO machines all seem to have clutches to ease startup. Some have auto mode where the PTO is shut off when the implement is raised. But wouldn't you have to throttle down before engaging the PTO again (or lowering the implement and have it auto engage)?

 

[CADplans]

I think the only difference is in the $$$$

How much money do you have,, versus,, getting on the tractor occasionally,,,:confused2:

:thumbsup:

 

[RickB]

With Live PTO the PTO cannot be started (or stopped) properly without stopping ground travel.
With Independent PTO both PTO and ground travel can be stopped and started independently of each other.

 

[japody]

Independent pto works well for me, particularly when bush hogging. Can start and stop the blades on the fly.

 

[jenkinsph]

I prefer independent pto for my uses. With all of my machines I can raise and lower the hitches without affecting the pto operation. All are independent pto and I would not want to go back to live or worst the transmission driven pto.

 

[ericm979]

Independent pto works well for me, particularly when bush hogging. Can start and stop the blades on the fly.

Do you throttle down to start the blades or does your tractor let you do it at normal (540 rpm pto) engine speed?

 

[TerryR]

I don't understand why one would want to engage the PTO at full engine speed. Isn't that a good way to break something?

A well-designed independent PTO has a clutch you can feather in to start heavy loads, like a wood chipper. Mine has as a two-stage action with the clutch pedal, where the first half of the throw controls the main clutch, and pressing further controls the PTO clutch. Works beautifully.

But I understand some are now designed with a switch that instantly fully engages the PTO. Some members here have complained about breaking shear pins when engaging a heavy load with such designs. I'd think that tractors with that design are to be avoided.

 

[IslandTractor]

I've had tractors with both live and independent PTO. I'll take the independent PTO any day. Other than having the added "risk" and potential complication of an electrical switch and hydraulic actuation compared to a simple mechanical clutch, there are no downsides I can think of for independent. Very convenient to just turn the PTO off while moving.

 

[IslandTractor]

Do you throttle down to start the blades or does your tractor let you do it at normal (540 rpm pto) engine speed?

You should throttle down before engaging independent PTO otherwise you will deliver big shock loads to both the implement and the PTO. Usually you don't go all the way to idle as engaging the PTO at idle can sometimes stall the tractor but just a few hundred RPM above idle works well and is safe.

 

[DK35vince]

A well-designed independent PTO has a clutch you can feather in to start heavy loads, like a wood chipper. Mine has as a two-stage action with the clutch pedal, where the first half of the throw controls the main clutch, and pressing further controls the PTO clutch. Works beautifully.

That would be a Live PTO with 2 stage clutch.
Independent PTO usually turn on/off by a switch.

 

[TerryR]

Thanks for explaining, Vince.

But why would anyone want a PTO system that doesn't let you feather in when you engage the PTO? Seems like a design sure to break things.

 

[IslandTractor]

Thanks for explaining, Vince.

But why would anyone want a PTO system that doesn't let you feather in when you engage the PTO? Seems like a design sure to break things.

There is a bit of a lurch when an independent PTO engages but no more so than the lurch that a truck makes when engaging first gear from a stop. The engineers who designed the tractor and truck presumably took those "shock" loads into consideration when designing and building the machinery.

 

[TripleR]

TractorData.com - Power Take-Off

We have most types and prefer hydraulic independent. We always reduce RPM on engaging/disengaging.

http://www.tractorbynet.com/forums/.../177989-disengage-pto-before-idling-down.html

 

[TerryR]

There is a bit of a lurch when an independent PTO engages but no more so than the lurch that a truck makes when engaging first gear from a stop.

Really? I've never seen a truck lurch when starting when operated by a competent driver. That's why gear-drive trucks have clutches.

The engineers who designed the tractor and truck presumably took those "shock" loads into consideration when designing and building the machinery.

How about the designers of the equipment that impose the loads? It's there that we see issues mentioned by members on this forum.

 

[IslandTractor]

Really? I've never seen a truck lurch when starting when operated by a competent driver. That's why gear-drive trucks have clutches.



How about the designers of the equipment that impose the loads? It's there that we see issues mentioned by members on this forum.

I don't recall ever seeing a post on TBN about failure of a tractor related to starting an implement with an independent (generally electrohydraulic activation) PTO. If I have any concerns about the one on my tractor it is only for the electrohydraulic switching, not the strain on the tractor. I engage the PTO at roughly 300rpm above idle to avoid stalling. I sense a lurch but no worse than the lurch felt when a bush hog hits a 2" sapling. I'm pretty sure that we'd hear about failures of implements if electrohydraulic independent PTOs were causing damage.

 

[IslandTractor]

Really? I've never seen a truck lurch when starting when operated by a competent driver. That's why gear-drive trucks have clutches.



How about the designers of the equipment that impose the loads? It's there that we see issues mentioned by members on this forum.

I don't recall ever seeing a post on TBN about failure of a tractor related to starting an implement with an independent (generally electrohydraulic activation) PTO. If I have any concerns about the one on my tractor it is only for the electrohydraulic switching, not the strain on the tractor. I engage the PTO at roughly 300rpm above idle to avoid stalling. I sense a lurch but no worse than the lurch felt when a bush hog hits a 2" sapling. I'm pretty sure that we'd hear about failures of implements if electrohydraulic independent PTOs were causing damage.

 

[GManBart]

Thanks for explaining, Vince.

But why would anyone want a PTO system that doesn't let you feather in when you engage the PTO? Seems like a design sure to break things.

You can ease the engagement of the PTO by lowering the engine RPM before flipping the switch/lever/control. Generally it's not necessary, but it won't hurt anything. I'm sure there's a certain amount of slip built into the system when it engages just based upon how smoothly they tend to engage.

 

[skipmarcy]

I've also owned tractors with both types and my current one with the independent is preferable to me. Mine has a rotary switch with an auto mode where the PTO will stop if you raise the hitch up to a certain height or push the clutch in, or manual mode where it stays on in those cases. In either mode you can turn it on/off with the push button switch on the steering column at any time. I almost always use it in manual mode. I don't like engaging at high rpms with the bushog on because of the mass to get moving but it's no problem with the finish mower, tiller or post hole digger. For the bushog I'll cut rpms back to around 1500-1800 before engaging.

 

[ericm979]

You should throttle down before engaging independent PTO otherwise you will deliver big shock loads to both the implement and the PTO. .

That's what I thought. But there are compact tractors with automatic independent PTO. If you raise the mower the PTO is automatically turned off. To resume mowing you'd have to reduce engine speed, lower the mower and then raise engine speed after the PTO automatically engages.

That seems to reduce the utility of the automatic PTO quite a bit. Which makes me wonder if on those machines the PTO engaging clutch engages gradually and is robust, in order to allow full engine speed engagement. (most of the tractors I have found with independent PTO have some sort of clutch, usually wet, that allows for gradual engagemnt.)

 

[DK35vince]

That's what I thought. But there are compact tractors with automatic independent PTO. If you raise the mower the PTO is automatically turned off. To resume mowing you'd have to reduce engine speed, lower the mower and then raise engine speed after the PTO automatically engages.

That seems to reduce the utility of the automatic PTO quite a bit. Which makes me wonder if on those machines the PTO engaging clutch engages gradually and is robust, in order to allow full engine speed engagement. (most of the tractors I have found with independent PTO have some sort of clutch, usually wet, that allows for gradual engagement.)

My tractor has the manual or automatic independent PTO.
In never use automatic (never found a use for it really). I use manual only and engage all my attachments at idle.