Engaging PTO at other than idle

OrangeGuy · Jul 6, 2004

Great discussion about how to engage the PTO on your CUT. Now my question is...How should you disengage the PTO? at high idle or should you reduce engine speed first?

My Allis Chalmers 620 tractor manual recommends that you engage the electric clutch at low speed (just as this discussion is recommending), but it recommends disengaging the PTO at high speed. Makes sense as the attachment will then coast to a stop putting no reverse forces on the PTO clutch. However, my Kubota tractors have hydraulically engaging PTO clutches that make sense with the low speed engaging, but at what speed should they be disengaged? At high speed, but what about the PTO braking mechanism? Will the attachment momentum of a bush hog or similar high momentum attachment quickly wear it out? Disengage at low speed and allow the PTO clutch pack to absorb the momentum? The manuals don't say.

Your thoughts!

OrangeGuy

ZackaryMac · Jul 6, 2004

I think an attatchment should be disengaged at low rpm, for a couple of reasons: 1) there is no hp being applied to anything, just momentum, so there will be less strain on everything than when under load, and 2) if you disengage at high rpm, you have NO control of your attatchment at all. If someone/something somehow got caught up in it, you'd have no way to slow it down any faster than it would do on it's own. If something got caught up in it at slowdown speed, at least you could kill the engine with the PTO engaged and stall the attatchment quicker.

Just a thought. /forums/images/graemlins/smile.gif

frank_f15 · Jul 6, 2004

I idel mine down, engage PTO bring engine up to PTO speed and start working, do the reverse when shutting off the pto. ithing the book on the tractor or mabey the RFM said to do it that way. BESIDES just seems like the right way to do it.

JWE · Jul 7, 2004

I engage mine at or below 2000 RPM (as stated, the manual says half throttle). I disengage at or below 2000.

John

ljh2 · Jul 7, 2004

JWE,

Er??? /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif I'm pretty sure the Max RPM of the BX is WELL below 4000. I think you'd be better off engaging/disengaging at or below 1500rpm. It's your rig, but I suspect it will serve you well for a lot longer if you do.

Anyway my 2cents on the whole issue is I engage mine at low RPM's and then trottle up to the needed speed for the use. I also try to throttle down before disengaging, especially with the rotary cutter, to slow the impliment down before disengaging. It brings the mower to a stop faster and will preserve the PTO brake.

JWE · Jul 8, 2004

Larry, you are right about the max RPM on the BX. It is around 3200 RPM. It idles at 1200 RPM so half throttle is about 2200 RPMs.

John

B2400 · Jul 9, 2004

When someone does this with their lawn tractor ( engage at WOT) I like to compare it this way: If you have a vehicle and everytime you take off, you rev the engine up as high as you can and dump the clutch, whats going to happen? 1- your going to wear your tires out ( same as drive belts) 2 your eventually going to tear up your drive train ie.. clutch, u-joints,gears,due to the immense shock load your placing them under.
As the others have said I engage and disengage at idle or nearly idle. Diesels make lots of torque and they're made to take a load at low rpm.

PineRidge · Jul 9, 2004

To start I also idle down, engage, and then up the RPM's to desired speed.

When finished, I idle down, and disengage the PTO slowly. I think it protects the brake on my PTO that way. Better than slamming it into the disengage position and a lot easier on the equipment I think.

JWE · Jul 9, 2004

It makes sense to me that engaging at a low RPM would be easier on the PTO clutch. However, I wonder why Kubota instructs to engage the PTO at half throttle.

John