Power loss between engine and PTO

[EuroYanmar]

83-87% pump efficiency for most. Awful for Tym. They must be using a centrifugal pump vs. probably a gear type for the others; wonder if they have an overpressure bypass like typical of others; wouldn't need with a centrifugal. That loss goes as heat that has to be cooled off in the hydraulic cooler.

Hi RalphVa,

Very interesting explanation. Is it for HST models only ?
So, for Branson F47 (4815 in US) we have only 11 % power loss with the same model of KUKJE engine.
Does it mean the pump is different ?
Where is this pump located ? In the transmission or on the engine ? What kind of pump is it ?

Thanks,

Phil

 

[ptsg]

Phil, keep in mind that the European Branson F47 uses a 3 cylinder Turbo engine, while the 4815 in the US uses a 4 cylinder engine, no turbo.

Regarding the pump, since we're speaking about PTO HP, on TYM and Branson, they use the power steering gear pump to engage the clutch pack. This applies to most brands actually.

I don't quite get what Ralph is trying to say about centrifugal pumps?

 

[EuroYanmar]

Phil, keep in mind that the European Branson F47 uses a 3 cylinder Turbo engine, while the 4815 in the US uses a 4 cylinder engine, no turbo.

Regarding the pump, since we're speaking about PTO HP, on TYM and Branson, they use the power steering gear pump to engage the clutch pack. This applies to most brands actually.

I don't quite get what Ralph is trying to say about centrifugal pumps?

Hi PTSG,

I did not notice this.
Maybe in 2021 they will share the same engine because of stage V regulations.
I wonder if Ralph refered to a different system in the HST transmission.
If yes, the problem stays with the gear model tractor.
My opinion is that even if cab TYM T474 and cab BRANSON 4815 looks like they have a different transmission.

Phil

 

[oosik]

Interesting - the Op Manual for my 2009 Kubota M6040 ( Hydraulic shuttle, I.E - geared ) says - - 62 engine hp, 57 PTO hp.

 

[K5lwq]

It would be nice if all Manufacturers would actually test their ratings rather than compute or guess at it.

My Branson manual shows both HST and gear tractors have the same PTO HP. We know that isn't correct.

There was one Branson model, do not remember which one, that when it was first released it produced way more HP than they thought. The Branson rep for the west was telling me the story so the numbers might be off from my memory. The tractor was rated somewhere around 60 HP and on the PTO dyno it produced over 90 HP. A few of them made it to customers before it was corrected and are still out there. I bet those guys love their Tractors. :laughing:

 

[ptsg]

I'm with K5. We can't really focus too much on any of these numbers. Most are just theory and not are actually tested.

For instance, TractorData specs for the Branson 3725:

3725R - Engine HP: 37HP - PTO HP: 33HP
3725H - Engine HP: 37HP - PTO HP: 32HP

I'm sure this is not accurate at all.

If the tractors were properly tested, I'm sure we would see a significant decrease on PTO HP over all brands.

 

[ericm979]

The PTO is not driven through the HST. Even on CUTS with live PTO. When the tractor is stopped and running the PTO, the HST is in neutral and not pumping oil. So it should be consuming little or no power.

Is PTO HP rated when moving or when stationary?

 

[ptsg]

The PTO is not driven through the HST. Even on CUTS with live PTO. When the tractor is stopped and running the PTO, the HST is in neutral and not pumping oil. So it should be consuming little or no power.

Is PTO HP rated when moving or when stationary?

Exactly. When the HST tractor starts moving, it's where the PTO HP will have a decent drop.

 

[RalphVa]

Hi RalphVa,

Very interesting explanation. Is it for HST models only ?
So, for Branson F47 (4815 in US) we have only 11 % power loss with the same model of KUKJE engine.
Does it mean the pump is different ?
Where is this pump located ? In the transmission or on the engine ? What kind of pump is it ?

Thanks,

Phil

I don't know about HST pumps so much. Just surmising from what I learned about pumps in specifying and observing them in 31 years of chemical engineering. Just one of the things some of us did. Most of the pumps are located inside the HST casing. The 1025R's pump (looks like a gear one) is located at the top rear of it.

Ralph

 

[RalphVa]

The PTO is not driven through the HST. Even on CUTS with live PTO. When the tractor is stopped and running the PTO, the HST is in neutral and not pumping oil. So it should be consuming little or no power.

Is PTO HP rated when moving or when stationary?

If this is so, why such a big loss? If it's direct gear, there should be something like 2 or 3% loss. Makes more sense that it's the PTO hp like to a bush hog while the tractor is underway. Then, the PTO hp while standing would be up substantially.