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PTO Engagement

#1

D

dannyboy44

Just got my first zero turn.

Can somebody explain why most brands (that I know of ) instruct to engage and disengage PTO at 1/2 or greater throttle?

Logic tells me to engage at idle and slowly increase RPM to minimize shock to the drive train.

I would think engaging at a high RPM would be a sudden jolt to components.

On my tractor i engage at idle to prevent undue torque to PTO shaft and implement.

I am really lost on this.

Thanks


#2

K

KennyV

You are correct... the lowest rpm you can expose stationary components to , the better everything will endure that shock...
Engines are being built with HP and Torque ratings that are generally at or near operation rpm. That Plus a reduction in flywheel (and associated rotational weight including clutch parts)... there is not enough inertia at lower (more desirable rpms)... Most modern engines will stall near idle rpm.... that will generate a lot of customer complaints, so the 'fix' is increase the rpm and assume that slippage will take care of the added shock load.

The best you will be able to do is find the lowest you can engage the clutch without killing the engine... :smile:KennyV


#3

D

dannyboy44

KennyV said:
You are correct... the lowest rpm you can expose stationary components to , the better everything will endure that shock...
Engines are being built with HP and Torque ratings that are generally at or near operation rpm. That Plus a reduction in flywheel (and associated rotational weight including clutch parts)... there is not enough inertia at lower (more desirable rpms)... Most modern engines will stall near idle rpm.... that will generate a lot of customer complaints, so the 'fix' is increase the rpm and assume that slippage will take care of the added shock load.

The best you will be able to do is find the lowest you can engage the clutch without killing the engine... :smile:KennyV
Click to expand...

Got it. So why is it that my tractor does not stall when i engage PTO at idle. Example I hook up a 6 foot flail mower, engage at idle and slowly raise RPM. Nowhere near stalling. Is this because my tractor is 40 HP diesel or just a whole different system on a zero turn with belts and all?


#4

Ric

Ric

dannyboy44 said:
Just got my first zero turn.

Can somebody explain why most brands (that I know of ) instruct to engage and disengage PTO at 1/2 or greater throttle?

Logic tells me to engage at idle and slowly increase RPM to minimize shock to the drive train.

I would think engaging at a high RPM would be a sudden jolt to components.

On my tractor i engage at idle to prevent undue torque to PTO shaft and implement.

I am really lost on this.

Thanks
Click to expand...

Your going to get a lot of different answers for this question and all maybe appropriate but not necessarily correct. Every manufacturer is going to be different, some will say engage at slow others will say mid throttle and others will say engage at full throttle. I'm not going to guess at what to tell you but I can tell you for sure I run a Toro Grandstand and my manual says to engage the PTO at full throttle, my CC ZTR says the same but the lawn tractors say different. My suggestion to you would be to check the manual and do what the manufacturer says to do and not what someone here on the forum is maybe guessing at.


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