Live Vs independent PTO

[IslandTractor]

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.)

My tractor also has the automatic mode. I don't use it. It is a safety device primarily and I understand the reason for it but I simply never raise my spinning flail mower when anyone is around and I never leave the flail running when elevated off the ground when I dismount.

 

[TerryR]

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.

No, and that's not what I said. But I have seen posts about shearing pins on attachments on startup with this system. See for example: this one

 

[Texasmark]

My 6530 has a live function in addition to Ind. There are no double clutch discs like in my 3000. The function is basically ind., but when in the live function you can depress the clutch and it will shut off the pto. I think I have 24 (wet) fluid cooled/"coddled" clutch discs in the system that act as shock absorbers, sequentially connecting.

It also has the switch controlled shut off for when you lift the implement at the end of a row (for example) and reinitiates it when you drop it. I also has a switch that operates the 3 pt. so you don't have to move the lever up and down each time you want to raise and lower; your arm rests on the control panel, thumb on one side, index finger on the other flip this way, flip that way implement up, implement down.

You pre set the lower limit of the 3 pt for setting depth of draft implements (and it does have the Ferguson system draft pressure selection lever also) with another arm height lever at the rear which you also use when you need to connect an implement and you can move the arms up or down. That's another nice feature. You have precision location capability with arm positioners with 10 holes and a drop pin to lock in place....no flopping all over. Then the ends of the arms have extenders for another 2" of fore aft adjustment and then the lift to move the arms up and down and finally the balancing leveler (like most tractors) where you can set the arms at different heights with respect to each other.

These niceties and more, including the Cummins B 3.3NA 4 cyl naturally aspired engine are the reasons I went with the badge.

 

[DK35vince]

No, and that's not what I said. But I have seen posts about shearing pins on attachments on startup with this system. See for example: this one

I had that issue with my 6' brush mower. (sheared pins when engaging at idle)
I put a slip clutch on my cutter to solve the problem.
My brush mower was the only place I notice the harsh start up.
7' finish mower, tiller, auger, Etc. it has been a non issue.

 

[TerryR]

I'd think a rotary cutter and a chipper would be the two most likely to be an issue. Both start fairly hard. Other tools I use don't have that much inertia and start pretty easy.

 

[ovrszd]

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

Yep. Me too. Both of my tractors have independent that is controlled by a linkage. I normally idle down and slowly engage. But occasionally I slowly engage with raised engine rpm. Either way it's possible to do it with minimal shock. Best part is not having to stop forward motion of the tractor to engage.

 

[IslandTractor]

No, and that's not what I said. But I have seen posts about shearing pins on attachments on startup with this system. See for example: this one

Yes, shearing pins/bolts would be a bother but one easily remedied by installing a slip clutch.

 

[LRover]

My Massey 1635 has an electrically engaged PTO but also has a "soft start" button that can be selected when using equipment like a brush cutter. Seems to work well and prevents the shearing of pins etc.

 

[IslandTractor]

My Massey 1635 has an electrically engaged PTO but also has a "soft start" button that can be selected when using equipment like a brush cutter. Seems to work well and prevents the shearing of pins etc.

Sounds like a desirable feature. Wish mine had that. I like the electrohydraulic activation but it would be nice to have a "soft start" option.

 

[Musdalen]

Is a Kubota L3901 a live or an independent PTO?

 

[ovrszd]

My Massey 1635 has an electrically engaged PTO but also has a "soft start" button that can be selected when using equipment like a brush cutter. Seems to work well and prevents the shearing of pins etc.

I've never heard of that. Excellent idea. My little JD is instant on so I always start it at idle. My Ford and Kubota are both linkage operated and you can soften the start a little with patience. Always start them at idle too.

 

[Texasmark]

Why would a manufacturer put 24 sequential clutch discs in a PTO system if it weren't to have a soft start? It doesn't take a rocket scientist to figure that the kinetic energy required to get a mower rotating at PTO rpm from a dead stop is one heck of a whack and since numerous things can interrupt the drive and re-apply something has to be inherent to prevent a problem. Get a parts breakdown on your tractor and look at the PTO clutch.....es!

An implement slip clutch isn't made for a soft start. It's made to disengage upon hitting an obstacle. If it were set for soft start you never would mow anything...it would slip......think about it! Slip clutches were here long before synchronized transmissions, live or independent ptos.

 

[IslandTractor]

Slip clutches may not have been designed to soften the start after PTO engagement but I don't see why they wouldn't work. A slip clutch doesn't "break" like a shear bolt with shock loads. It just gives until the load is lower than what the clutch spring compression is set for then the clutch reengages and transmits power. When mowing and hitting a stump the slip clutch reengages as soon as you pass over the stump and the same thing would happen with a "hard" PTO start.

 

[Texasmark]

Slip clutches may not have been designed to soften the start after PTO engagement but I don't see why they wouldn't work. A slip clutch doesn't "break" like a shear bolt with shock loads. It just gives until the load is lower than what the clutch spring compression is set for then the clutch reengages and transmits power. When mowing and hitting a stump the slip clutch reengages as soon as you pass over the stump and the same thing would happen with a "hard" PTO start.

Sounds good in theory and I agree. Problem is getting that sweet spot on the spring tensions and having that pressure remain, especially considering rusted plates that press against the braking discs hampering proper operation by most folks (self included) leaving shredders out in the weather. The manual calls for setting the tension by spring length. Well that's all well and good but that isn't all there is to it. And on the subject, that's the same type multi-disc setup as is used on the disc type tractor IND. pto, only not as many. I think the ones I had were around 3-5 discs.