Measuring/calculating PTO speed (not PTO speed = Machine speed / implement speed)

[wbj2]

I DAGS and searched the forum for PTO speed etc.

So. I have a Hinomoto N279 32HP tractor. Maybe I bought badly as it does not even have its own section here

However.. The N279 has a 4 gear/speed PTO. I know the flail mower I have bought requires a 540 RPM PTO speed. But I do not know for the N279 what PTO speed results from what engine speed in each PTO gear. The Tacho has no indication of PTO speed for each PTO gear.

So how do I measure the PTO speed? I tried writing on a spline with liquid paper. But 540 RPM is what.... 9 per second. Try counting that.

To add to that, the 4 PTO gears do not make sense to me: they do not go 1=slowest 2=a bit faster...etc. They seem to duck and dive, based purely on non-measure obs.

Or do I just wing it, going as high-gear as I can without labouring, running at 1500 RPM of the 200RPM of the N279, and yet getting a decent thrashing?

I understand that the whole thing revolves around also looking at Forward Movement Speed and is all a balancing trick. But I would like to know the figures as a starting point.

I notice Amazon sells a digital tach that looks identical to Princess Auto's (all the makes look the same and are probably made by the same Chinese company) for about $25.00

 

[oldtimer 66]

PTSG noted the 4 pto speeds. 540, 750, 860, 1000. The PTO speed is directly proportional to the engine speed. You could idle the tractor and count the revs. in each of the 4 pto speeds. Lets say 900 rpm is engine idle speed and 2500 rpm engine speed is the 540 rated PTO speed. Therefore you would only need to count 3.24 revs per second. Think of it as a waltz tempo, 3/4 time. Three beats to the measure but at double time, 6/8 time. Lawrence Welk EH! The 860 PTO speed would be like a 4/4 time as in a Sousa march, again at double time plus, Stars and Strips for Ever. Easy peazy I say. LOL.

 

[ROUSTABOUT]

That or similar^

Just don't get anywhere close to that spinning shaft, especially at 540. I'd probably mount it somehow to take some measurements, no way I'd hold it close to the shaft.

People hold them close to shafts regularly. That's how they measure speed. Oscilloscope works the same way. Timing light works on spark plug engines.

 

[sea2summit]

People hold them close to shafts regularly. That's how they measure speed. Oscilloscope works the same way. Timing light works on spark plug engines.

Holding it up against a spinning lathe, an engine on a stand or anything else spinning in the shop is much different in my mind than the body position/exposre required to get close to a tractor's PTO shaft. I'm not safety Sally, feel free to do whatever you want I just don't see myself getting that close to a tractor's spinning PTO shaft.

 

[ROUSTABOUT]

Holding it up against a spinning lathe, an engine on a stand or anything else spinning in the shop is much different in my mind than the body position/exposre required to get close to a tractor's PTO shaft. I'm not safety Sally, feel free to do whatever you want I just don't see myself getting that close to a tractor's spinning PTO shaft.

Well un hook the shaft and shoot the pto stub itself.

 

[animal12]

Take your readings off the driveshaft .The driveshaft is the same rpm as the output shaft . If your that close that the spinning shaft is too close for comfort then your too close .
animal

 

[Brendanspapa]

Check to see if there is a optical tachometer app for a cell phone .....

There’s one for iPhones, called video tachometer. There may be some for Android phones too.

 

[ScubaJonL]

Check to see if there is a optical tachometer app for a cell phone .....

THIS IS THE ANSWER! Don’t waste a dime.

I’ve never used the tach app but I found an adjustable strobe light app will “freeze” the shaft when your strobe frequency matches PTO speed. Make sure it’s set to RPM and not Hertz or you’ll have to do math.

Be warned it should also “freeze” it at 270 (540/2), 180 (540/3), 135 (540/4), … and 5.4 (540/10) flashes per minute. Double check that at 1080 flashes/min you should now see the back side of the shaft every other flash.

Just another way mathematics relates to your every day life.

 

[OldNick]

I have a compact international 234 diesel, I was debating to get a pto generator or a gas. when I seen the pto generators needed to run at 840, I checked for the pto speed on my tractor,it would need to run at 2200 RPM's to get 840 at the pto. I bought a gas generator. I didn't want the engine to run that long at 2200 rpm. but I would run yours at that RPM since it is not for half the night and all day at a time. I would see no problem with 2200.

Yeah as I said I am not happy at running a diesel at 2000-2500 rpm. IT makes a lot of noise and just _feels_ wrong. This from someone who has run a tractor for 30 years and a Dozer and Loader for 10. I used to get them up to higher revs, but only in bursts. To run it constantly at 2000-2500 RPM just does not work for me.

HOWEVER....there is a lot of opinion here that that's the way to run a diesel under load!

I think I will go back to tractoring by the seat of my pants, hoping I have a good enough feel for a labouring engine and adjusting accordingly.

 

[OldNick]

There’s one for iPhones, called video tachometer. There may be some for Android phones too.

There are, but I could not find one that actually worked