Help me understand PTO speed

[Sean2202]

Greetings,

Hopefully someone can help me out here. I have a Kioti RX6010C. Reading in the manual it states "The rear PTO rotates at 540rpm when the engine speed is approx. 2,444". This tractor has been used to operate a SR60 deep tine aeration machine for a few years and there always seems to be trouble so I am trying to understand if the tractor is not right to operate this machine or is it the machine itself. We operate the aeration machine in first gear lowest range with turf tires and the speed in the tractor owners manual states 1.16mph

Here is the new recommendations that I just received from the SR60 aeration machine which I never had a book for until today.

[*]

• The machine should be operated at 1mph, 1.16 seems pretty close to me.
• The SR60 aeration machine should be operated at 450PTO with short tines or 400PTO speed with long tines. We use the long tines.
• We operate the tractor at about 2100RPM when using the machine.
• What am I missing or doing wrong here?
  
  Is this the wrong tractor for this application?

Thanks for any help
Sean

 

[KennyG]

The only issue I can see is that, if my math is correct, you should run at about 1800 engine rpm.

 

[Sean2202]

How exactly did you figure that out...Math is not my strong point.

 

[oosik]

Well - - 2444 engine rpm will give you 540 PTO rpm. So what engine rpm( X ) will give you 400 PTO rpm?


2444/540 as to X/400 this gives you . 540X = 977,600 . Do the division and you get - 1810 rpm's.

OR figure it this way. Divide 2444 by 540. This equals = 4.54. This tells you that the engine must turn 4.54 revolutions to get one revolution of the PTO shaft. You want 400 revolutions of the PTO shaft. Multiply 400 time 4.54 = 1810 engine rpms to get 400 PTO rpms.

 

[bcp]

Find a ratio calculator and fill in the blanks. Here's one:



Bruce

 

[hosspuller]

Help me understand …. What is the trouble with the SR-60 when you're using it ? Besides operating it too fast...

 

[CobyRupert]

Right.
Here's another way. Use units when doing your math so you know the answer makes sense.
The manual tell you Engine (rpm) to pto (rpm) is: 2440 (eng)/540 (pto). This is also the same ratio as saying 540 (pto)/2440 (eng.) Then pick the one of these to multiply by. Pick so that the some units "cancel out" and your left with the answer that makes sense.

You desire 400 rpm (pto):
400 (pto) x (2444(eng)/540(pto) = 1810 (eng) rpms because "pto" divided by "pto" cancels each other out and you're only left with "eng" rpms.

so.....
how fast will you be going at 1810 rpm in first gear?

1810 rpm (eng) x 1.16 mph/2444 rpm (eng) = .86 mph

We sort of took a short cut and skipped a step. Could of also said

1810 rpm (eng) x 1.16mph /540 rpm(pto) x 540 rpm(pto)/2444 rpm (eng) = .86 mph, again ALL the units cancel each other out except for mph.

 

[Sean2202]

Thank you all for the explanation on the PTO speed. Thanks for the math and calculator! I will try this and see if it clears up some issues.

It is a very old violent running machine that was left outside many years and has a lot of neglect. I just sourced a manual for it so I will try to do some reading on it and post up any updates when I have them. The machine isn't used much about 40 hrs per year if that.

 

[CobyRupert]

I don't know anything about aeration machines, but if you're forward ground speed doesn't exactly correspond with rpm of the aerator, does it become more of a "roto-tiller" than an aerator?

 

[ChevyBlazerBoy]

You can buy a non contact digital tachometer on amazon for 20 bucks. It should be able to give you the rpm of your pto. You just put reflective tape on it. Point at it with the laser and thats it. Digital Photo Laser Tachometer Non Contact Tach RPM Meter Amazon.com: Digital Photo Laser Tachometer Non Contact Tach RPM Meter: Automotive

 

[rademamj1]

Same number I came up with. 1807rpm in low gear should do the job at a 400PTO speed which comes out to .88mph actual ground speed. Your tractor should have no problems doing the job. It's a very slow methodical process. Find a testing area to get your procedures right, before doing it on the greens and fairways. I am always fascinated watching the SR60 at work.

 

[Sean2202]

@CobyRupert I have used many different types of aerators and yes it can be a "rotor-tiller" in certain conditions. We have Toro 648 walk aerator and it can take quad tines. If the speed is set too low, tines too large, root zone very shallow this can all lead to tearing of the turf and rotor tilling. The SR60 had 14" tines that go deep into the ground. The speed that it is currently run it tears when first going into the ground which tells me the ground speed is too fast. This machine is only used on golf greens which are a mix of sand and native soil from 1917 when the course was constructed.

@ChevyBlazerBoy good thought on the photo tach! I have one and use it often for checking RPM on machines. Never thought about using it on a PTO shaft! Thanks for the tip.

The SR60 is quite a overbuilt machine. I think it weighs just under 1 ton.

 

[CobyRupert]

.. Reading in the manual it states "The rear PTO rotates at 540rpm when the engine speed is approx. 2,444 ( eng. rpm).......in first gear lowest range with turf tires and the speed in the tractor owners manual states 1.16mph

Here is the new recommendations that I just received from the SR60 aeration machine which I never had a book for until today.

[*]

• The machine should be operated at 1mph, 1.16 seems pretty close to me.
• The SR60 aeration machine should be operated at 450PTO with short tines or 400PTO speed with long tines. We use the long tines.
• We operate the tractor at about 2100RPM when using the machine.

• 
  
  @Sean2202:
  
  ...but you can see that with a gear tractor (vs. a hydro), that when you adjust engine speed for correct pto rpm you're also adjusting ground speed (and vise-versa)....so it may be impossible to get 1 mph at 400 and/or 450 pto rpm. Now whether it still works at a slower ground speed in 1st gear (or faster in 2nd?); or turns into a "roto-tiller" is the experiment.

 

[Sean2202]

We have used it in first gear and second gear Lowest range in the past. I think that the RPM is just too high.