What does "At rated engine RPM" mean?

[TNhobbyfarmer]

I did some spraying this weekend with a PTO driven sprayer. It is helpful to know tractor speed when spraying. My users manual has a chart that tells speed in all gears "at rated engine RPM". What does that mean?

 

[kuboman]

I did some spraying this weekend with a PTO driven sprayer. It is helpful to know tractor speed when spraying. My users manual has a chart that tells speed in all gears "at rated engine RPM". What does that mean?

Usually means max underload rpm which is usually 2-300rpm below max high idle rpm.

 

[wrooster]

I did some spraying this weekend with a PTO driven sprayer. It is helpful to know tractor speed when spraying. My users manual has a chart that tells speed in all gears "at rated engine RPM". What does that mean?

i would take "at rated engine RPM" to mean the engine RPM associated with maximum torque.

For example, the gearing will be set up such that the PTO will be turning at 540RPM at (or slightly above) the engine RPM associated with maximum torque. This is by design.

Wrooster

 

[LD1]

I have always taken it at WOT. MAx RPM.

When you are looking at the speed chart, it will list the MAX speed for each gear "at rated RPM", and that is the MAX the tractor will go in that gear. (Unless you are going down hill and hit the clutch)

 

[dynasim]

It is the speed at which the pto(not engine) turns at 540 rpm. The power and speed references for all tractors I have been follow that rule.

Chris

 

[jonyyuma]

I have always taken it at WOT. MAx RPM.

When you are looking at the speed chart, it will list the MAX speed for each gear "at rated RPM", and that is the MAX the tractor will go in that gear. (Unless you are going down hill and hit the clutch)

Overspeed, which might be 750rpm above max rating, might get the connecting rods mixed up???

 

[LD1]

Overspeed, which might be 750rpm above max rating, might get the connecting rods mixed up???

That would only happen IF coasting down a big hill with the clutch in and you let the cutch out in too low of gear

 

[rbargeron]

I did some spraying this weekend with a PTO driven sprayer. It is helpful to know tractor speed when spraying. My users manual has a chart that tells speed in all gears "at rated engine RPM". What does that mean?

Pretty sure they are talking about the rpm that would give 540 pto rpm. Calibrating a sprayer for accurate delivery of material per acre takes some doing.

 

[murphy1244]

That would only happen IF coasting down a big hill with the clutch in and you let the cutch out in too low of gear

Would they switch cylinders then? I hate when that happens.

 

[jonyyuma]

Would they switch cylinders then? I hate when that happens.

I really don't know if you could get one to go into overspeed?? I remember seeing it on some big trucks dashes years ago?? As to breaking connecting rods only had that happen twice, and it was on single-cylinder engines. Once i promoted it by holding govenor on Mini-bike for a little more speed?? My tractor has a good govenor, but i still don't try to force revs...Only operated it WOT with the tiller fully engaged into the clay soil..But it is a mess when a diesel pops a piston and starts that old hard slap??Ask me how i know it sounds on a 1000+hp..Gen-set???