Pto speed on mower

So l have been pricing mowers these last few weeks.
Just a plain 3m mounted without conditioner . Usual wide range of prices but on calling one dealer for the final round of getting the best price he asked if l wanted a 540 or 1000 pto model. Both mowers exactly the same apart from pto speed. Oh the 1000 pto one will cost one hundred more.
Will it be any better? All the tractors here are 540 , 540 eco and 1000. Thanks
 

Mur Huwcun

Member
Livestock Farmer
Location
North West Wales
Any chance you or anyone can explain this to a simpleton like me.

High speed, low torque. The faster the shaft spins, the less torque loading it’s transmitting. Look at car driveshafts, about an inch diameter but spinning at ridiculous speeds. Shaft from tractor engine into transmission is spinning at engine speed therefore is quite a thinnish shaft but then the speeds are dropped down in the transmission and then trumpet reduction to turn the wheels slowly, the shaft sizes are doubling as the speed halves.
 

john432

Member
Location
Carmarthenshire
This is where I wish I had the ability of @Cowabunga to explain.

Horse power or kilowatt power ,is defined as torque X rpm , so a big steam traction engine could have the same hp rating as a small very fast petrol engine. One has masses of torque (leverage)at a very low speed , petrol engine the opposite.
So on a mower, to put 50hp through the pto shaft, , turning all most twice as fast ,will reduce the leverage strain on the joints by half.
 

Bury the Trash

Member
Mixed Farmer
High speed, low torque. The faster the shaft spins, the less torque loading it’s transmitting. Look at car driveshafts, about an inch diameter but spinning at ridiculous speeds. Shaft from tractor engine into transmission is spinning at engine speed therefore is quite a thinnish shaft but then the speeds are dropped down in the transmission and then trumpet reduction to turn the wheels slowly, the shaft sizes are doubling as the speed halves.
With that taken into consideration Less strain on the tractor engine as well of course.if the engine is also working at higher revs as ours needs to... to get 1000 shaft speed when its selcted
 
Last edited:

Horn&corn

Member
I asked for our rear mower on 540 so I could use eco but dealer recommended 1000 as then the speed just keeps dropping as power goes through the drive train. I’ve actually never mowed without one on the front so would have never had opportunity to test other engine speeds etc
 

Mur Huwcun

Member
Livestock Farmer
Location
North West Wales
Simplest way is
If everything else is on 540
Then get 540
Saves swapping stub over all the time
It was always a pain with the Claas baler when it was on 1000rpm, when everything else is on 540

Nearly everything comes on 6 splines now anyhow regardless of what speed they need. Only the real power hungry machines need the extra contact area of 21 splines
 

Cowabunga

Member
Location
Ceredigion,Wales
The only possible advantage of the 1000 over the 540 pto speed is 1000 would be about half the torque so joints etc should last longer. Can't think of anything else.
Spot on. Except that its not only joints but shafts themselves. If you look at it the other way around, a 1000 rpm drive can take up to twice as much horsepower for the same size and strength of components as one turning at 540.

However, it has to be remembered that at the final working point of the implement, it has to be geared down to the same speed as if its primary drive was 540, so those components need to be much stronger if the power put into driving the system is higher to start with [a bigger tractor].
 

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Man fined £300 for bonfire-related waste offences

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Written by William Kellett from Agriland

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A man has pleaded guilty at Newtownards Magistrates’ Court to waste offences relating to a bonfire next to the electrical sub-station on the Circular Road in Newtownards, Co. Down.

Gareth Gill (51) of Abbot’s Walk, Newtownards pleaded guilty to two charges under the Waste and Contaminated Land (Northern Ireland) Order 1997, for which he was fined £150 each and ordered to pay a £15 offender’s levy

On June 25, 2018, PSNI officers went to Gill’s yard, where they found a large amount of waste consisting of scrap wood, pallets, carpet and underlay.

Discussion with Northern Ireland Environment Agency (NIEA) officers confirmed the site...
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