L3902 PTO
- Thread starter GigEmAggie87
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NCL4701
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L4701, T2290, WC68, grapple, BB1572, Farmi W50R, Howes 500, 16kW IMD gen, WG24
Based on the spec sheet on Kubota’s website if your L3902 has the gear transmission the PTO is “live continuous”. If HST transmission it’s “live independent with hydraulic clutch”. While “live continuous” is engaged/disengaged by the clutch, it isn’t transmission driven so the rotational inertia of an implement can’t backfeed into the transmission to push you after you disengage the clutch to stop the PTO.
For comparison, note the spec for the L3302 gear drive which is “transmission driven with overrunning clutch”. Being transmission driven, an overrun clutch is needed so they built one in as an integral part of the L3302 gear drive.
North Idaho Wolfman
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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
TheOldHokie
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L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Yes, I have the HST transmission. Its a new machine, and when I was doing some mowing yesterday with a PTO driven attachment, I accidently hit an object and the tractor turned off. I am of course concerned I did not damage transmission with the sudden stop.
Thanks for the information!!
TheOldHokie
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L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
An ORC does nothing to protect agsinst hitting things. For that sort of protection you want a PTO shaft with slip clutch.
Dan
If that attachment has a slip clutch, it needs to be adjusted. If it doesn't have a slip clutch or shear pin, get one.
What does 'live continuous' mean? If it doesn't have a separate clutch, couldn't power still backfeed into the transmission?
NCL4701
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L4701, T2290, WC68, grapple, BB1572, Farmi W50R, Howes 500, 16kW IMD gen, WG24
Uses the same clutch to engage/disengage but it isn’t transmission driven (that’s the “live” part) so it doesn’t backfeed the transmission. How exactly the mechanics of that work, someone else would have to answer. I’ve never owned or operated a tractor with that type of PTO.
North Idaho Wolfman
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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Some models have 2 input shafts one direct driven directly off the Crank for the PTO feed, and one off the clutch for the transmission feed.
Some the PTO clutch is after the HST driven off the same shaft as the input to the HST.
TheOldHokie
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L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
The PTO on my 1980s gear drive B7200 is transmission driven but it doesn't back feed because OEMs got smart around 1960 and started putting one way drives in the PTO itself.
Dan
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I understand most of this. We've had
*AC model C with transmission drive PTO, no brakes, that was exciting, never heard of over-running clutch
*MF model 50 with two-stage clutch, major improvement
*Ford 3930 with independent hydraulic clutch-brake, good enough
*K L35 with GlideShift and internal over-running clutch (I think), but unnecessary since transmission has separate hydraulic clutch
*Ford 1520 with tranny drive I think. In any case, you have to stop tractor to engage PTO.
I'm just not understanding the difference between the L2501, L3301/2, and L3901/2 gear drive setups. They all have single clutches and no PTO clutch, except some have over-running clutches and some don't. Some are called 'transmission driven' and some are called 'live continuous'. Without WSMs it's hard to understand the power flow.
TheOldHokie
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L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
The implementation details are interesting but all that really matters is operation. Live independent means exactly that. Disengaging the foot operated transmission clutch disengages the drive wheels but has no effect on the PTO. Just like first stage of a two stage clutch. The PTO has its own independent clutch that powers it. Unlike a two stage clurch it can be disengaged without disconnecting the drive wheels.
They all have overruning (one way) clutches of some sort in their respective PTO drivelines that prevent inertial feedback generated by a spinning implement from powering the drive wheels. The grandaddy of them all the old Ford N series is an example of a design that had the PTO shaft solidly coupled to the drive wheels. Depressing the drive wheel clutch disconnected the engine from the wheels but the spinning PTO mass was still connected and would continue to power the wheels leading to "Whoa Nellie !!!!" events. The workaround was to put an external slip on one way (overrunning) clutch on the PTO and then connect the implement to it. Did not take long for OEMs to realize the mistake and move that one way clutch inboard.
Dan
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