PTO Speed.....can I run less without harm?

[Fordiesel69]

At 540rpm PTO that places my engine at 2450 RPM. With a woods 72" rear finish mower, can I run at 2000RPM to 2200RPM without harming the tractor? It is a new holland boomer 30. I get just as good of cut at the slower RPM, but not sure if this is harmful.

Grass does not get terribly long either so engine does not have to work hard.

 

[k0ua]

At 540rpm PTO that places my engine at 2450 RPM. With a woods 72" rear finish mower, can I run at 2000RPM to 2200RPM without harming the tractor? It is a new holland boomer 30. I get just as good of cut at the slower RPM, but not sure if this is harmful.

Grass does not get terribly long either so engine does not have to work hard.

Thats fine, you are not going to hurt anything.. typically the cut is not quite as good at lower speeds, but if you are happy with it I don't see any harm. Just less noise, probably less fuel used, and as long as the tractor is not lugging down, which it does not seem to be, then I think you are fine. Obviously if the grass was higher or wetter you might have a problem then. I often bushhog. (trimming not mowing a field) at much lower RPM's mainly as a safeguard to not throw rocks so far if I hit any. I have some rough areas to trim with the rotary cutter.

James K0UA

 

[MHarryE]

Classical energy formula E=1/2 mass x velocity squared. If you increase the speed to rated speed, the blades will carry more energy to carry them through the cut, and that energy increases with the square so for example increasing from 400 rpm to 540 rpm increases the energy at the blades by 1.8 times. It allows them to carry through the cut and throw the cut material out of the way better. So there are advantages to running at rated speed but if the slower works for you... Mine doesn't. At lower speeds there is more hammering and banging going on, but I am often cutting tall, heavy grass with some brush where blade momentum is most important.

 

[Combustix]

Depending on grass height I will run from 1800 to 2200. 540 is about the same rpm on my b2710

 

[bigbull338]

youll be fine running at 2000 to 2200rpms.i have yet to run the pto at 2450rpms for 540 pto.when i shredd i run at 2000rpms give or take.

 

[foreman Etexas]

youll be fine running at 2000 to 2200rpms.i have yet to run the pto at 2450rpms for 540 pto.when i shredd i run at 2000rpms give or take.

Same here even pulling my 15ft batwing I dont run but 2,000rpm's

 

[TripleR]

I run mine at or near full 540, but as you can see, this varies. I seem to remember an old really long thread on this.

Some of our older tractors lost gauges long ago, so on those my brothers guesstimate just like I always did and they are still running; no problems.

 

[bigbull338]

I run mine at or near full 540, but as you can see, this varies. I seem to remember an old really long thread on this.

Some of our older tractors lost gauges long ago, so on those my brothers guesstimate just like I always did and they are still running; no problems.

on those tractors that the rpm meters no longer work.you can tell just about what the rpms are just by listening to the moter.

 

[TripleR]

on those tractors that the rpm meters no longer work.you can tell just about what the rpms are just by listening to the moter.

You sure can; one of them I have driven since dad bought it new in 1955; Massey Ferguson since new in 86, Case 995 was well used when we bought it, but you can just "feel" it.

My brother has put aftermarket oil pressure and temp gauges, but the rest is by instinct. We use a stick for a fuel gauge.:laughing:

 

[Jay4200]

Classical energy formula E=1/2 mass x velocity squared. If you increase the speed to rated speed, the blades will carry more energy to carry them through the cut, and that energy increases with the square so for example increasing from 400 rpm to 540 rpm increases the energy at the blades by 1.8 times. It allows them to carry through the cut and throw the cut material out of the way better. So there are advantages to running at rated speed but if the slower works for you... Mine doesn't. At lower speeds there is more hammering and banging going on, but I am often cutting tall, heavy grass with some brush where blade momentum is most important.

I think mower blade cutting ability is more of a momentum thing then an energy thing. If so, linear with velocity, not squared.

JayC