Live Vs independent PTO

[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.