What does this mean?

mcfarmall

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I was browsing through the M5660 manual that I printed off the internet and in the section on the PTO/engine hour readout operation there was an illustration that showed what the display would look like in the PTO mode and it was 540 n/m.

What does n/m stand for? I can figure out r/m to be a funky shorthand for rpm but the illustration clearly shows n/m...I even showed the illustration to my wife without prior discussion and asked her, she said n/m.

In my vocation, n/m is a metric torque value that stands for Newton/meter.

Here is from acronymfinder.com

Acronym Definition
N/M Not Meaningful
N/M Nevermind
N/M No Message
N/M No Marks (cargo)
N/M Newton Per Meter
N/M Nuthin' Much
 

GeoHorn

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Nm is one method of indicating Newton-Meter (or metre) and is a measure of determining torque. As a form of misapplication of the term, since torque represents energy transferred or expended per angle of revolution,... it is sometimes mis-used to indicate revolutions.
 

Rosher18

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N is a notation for a quantity of things, in this case revolutions, as others have pointed out.

It seems like they're reminding you that you're not looking at engine rpm by using units of n/m instead of rpm.

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GeoHorn

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N is a notation for a quantity of things, in this case revolutions, as others have pointed out.

It seems like they're reminding you that you're not looking at engine rpm by using units of n/m instead of rpm.

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This response is not a criticism of your very good comment.... but, in conjunction with your comment.... it seems to be another misapplication or lack of conformity to when they then specify PTO output as “540 RPM” ... (the 540 refers to PTO not engine.)
 

mcfarmall

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Thanks for the replies...seems like with the right LCD panel Kubota could have easily done something that would have been a little easier to understand. Maybe the PTO icon with the rotational arrow and the abbreviation rpm. Oh well, until I get a job in the engineering department at Kubota, I'll just have to be happy with n/m and whatever it may mean.
 

Palmettokat

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how about they don't us rpm for most think of engine speed when they read or hear that so they use N/M for number/minute? or 540 N/M.
 

Rosher18

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This response is not a criticism of your very good comment.... but, in conjunction with your comment.... it seems to be another misapplication or lack of conformity to when they then specify PTO output as “540 RPM” ... (the 540 refers to PTO not engine.)
Very good point. I hadn't considered that everybody thinks of PTO rpm as that, rpm!

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Russell King

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Most of the world (outside USA) understands that n/M better than RPM. I think the use of the SI (metric) system drives it somewhat.

We should have converted in the 70s and be done with the change.


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angelo c

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Most of the world (outside USA) understands that n/M better than RPM. I think the use of the SI (metric) system drives it somewhat.

We should have converted in the 70s and be done with the change.


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Well young fella....that's where's yer wrong....WE are "most of the World" in 'MURICA....and e'ry body else is just places to fly over.... :)
 
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GeoHorn

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Well young fella....that's where's yer wrong....WE are "most of the World" in 'MURICA....and e'ry body else is just places to fly over.... :)
You’re being tongue-in-cheek, of course, ... but that is a curious example of how a typical ’merican-bubba has his own version of snobbishness. (Usually reserved for elitists.)
 
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SidecarFlip

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This is way over my head....lol I tend to think it was a mis print myself. I am surprised he read an owners manual. Most don't today. They watch a Pew Tube video and become an instant expert.
 
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Thunder chicken

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on a lot of turbine powered airplanes, 'N' is used as 'rotational speed' on engine gauges. I'm sure there's a fancier way to say it. I assumed it was a German or french word but having spent some time googling it now, cause now I want to know after all these years, there seemed to be no good answer on the interweb.
Np - prop rpm
Ng/ N1- Gas generator rpm

I like the tractor display this way, we can see exactly what the PTO is doing. With no mark on the tach it's easy to forget what rpm the engine should be at!
 

GeoHorn

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Not trying to be contrary, but I believe when a gauge is labelled “N” it refers to “percent” of RPM of the primary (N1) or secondary (N2) turbine wheel.
I’ve got thousands of hours operating/teaching/examining pilots in turbine powered airplanes and in the ones I flew the “N” doesn’t refer to the rotational speed. It refers to the turbine wheel which the designated “N”-gauge is sensing. N1 would indicate the primary wheel (or the first one inline such as compressor), N2 the secondary (such as an output or propeller-shaft.) The gauge is usually inscribed to indicate PERCENT of RATED-RPM, not the actual RPM and that is a correct usage of the “N” term (although there are exceptions to this as chosen by the mfr’r.* Beechcraft and some others use percent of N1 but RPM of N2 and that is because their N2 gauge is actually labelled “Prop” rather than a turbine wheel.

*even mfr’s sometimes depart from the engineering terms

At least that’s the case usually with the airplanes I recall operating. I’ve slept since then and cannot figure out how I ever had time to go to work since I retired.
 
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GreensvilleJay

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gee if Metric is soooo great... WHY is it here in Canada, where we've been 'metric' for decades , do the cops and media ALWAYS say 'be on th elookout for the bad guy, 6 foot 3, 210 POUNDS ????
meanwhile temps are in *C, speeds in Km/h...
sigh

Jay
 

GeoHorn

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My buddy says he now weighs 14 stones. 🤔
 

JerryMT

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on a lot of turbine powered airplanes, 'N' is used as 'rotational speed' on engine gauges. I'm sure there's a fancier way to say it. I assumed it was a German or french word but having spent some time googling it now, cause now I want to know after all these years, there seemed to be no good answer on the interweb.
Np - prop rpm
Ng/ N1- Gas generator rpm

I like the tractor display this way, we can see exactly what the PTO is doing. With no mark on the tach it's easy to forget what rpm the engine should be at!
I worked with Rolls-Royce commercial turbofan engines and they had three spools so the was N1, N2 & N3 for the fan/low pressure turbine, intermediate compressor/intermediate turbine , and the high compressor/high pressure turbine, respectively.