TC45D load performance

[dynasim]

Sorry about not listening to you RickB.

I assumed that the PTO was HST driven since there is a significant loss in PTO HP between the 45A and 45D. As I said, I am learning.

I plan to mount the generator on the tph, and couple it(with the operational position being on the ground) with a standard PTO coupling. There won't be any side forces on the tractor's pto shaft.

Thanks for the caution and advice.
Best Regards
Chris

 

[RickB]

Chris, RickB was a NH tech for many years. You can take his word as fact on issues regarding NH tractors.

Gosh Jim, I was kinda hoping for a blanket endorsement of my input on any topic, not just New Holland Tractors!!! Anyhow, thanks for the kind words. You know me; seldom wrong, but never in doubt.
Seriously, I try very hard to post accurate info, but unfortunately it sometimes doesn't work out to my expectations.

 

[jinman]

I assumed that the PTO was HST driven since there is a significant loss in PTO HP between the 45A and 45D. As I said, I am learning.

Now that is a very good observation, Chris. There is indeed a difference.

On the gear tractor, all that is there to sap engine HP is the engine mounted hydraulic pump that drives the 3PH and/or the FEL. Anytime you are using either of those, there will be less than full HP available to the PTO. That is the same for either the 45A or 45D.

On the 45D, there is a "charge" pump attached to the input shaft going into the HST transmission. That pump runs all the time and circulates HST hydraulic fluid up through the HST cooler and supplies it to the input to the HST transmission. That saps some HP that a gear tractor would not have lost. Therefore, the PTO HP is slightly less on the HST model.

The PTO clutch/brake pack is hydraulically actuated by the main engine mounted pump on both the 45A and 45D; therefore, I think the HST charge pump is solely responsible for the difference in PTO horsepower.

Am I way off base here RickB?

 

[RickB]

The charge pump, the hydro pump and the load caused by the regulated charge pressure buildup would all contribute to parasitic HP loss. If you really want an eye opener, look up Nebraska test results for '70's era IH farm tractors that were tested with both gear and hydrostatic transmissions. An example is the IH 966; Gear drive PTO HP 96.2 Drawbar HP 80.4. IH 966 Hydro PTO HP 91.4 Drawbar HP 68.08. Guaranteed the hydrostatic version had a higher maximum fuel setting on the injection pump than the geardrive. Comparative drawbar HP figures for today's compacts are hard if not impossible to find. Wonder why?

 

[dynasim]

That is interesting. What that means is, for example on a PTO generator, the parasitic losses are directly proportional to engine speed(assuming the supply pump is gear driven), and the optimimum engine speed for driving a 15 hp(10 KW) generator would be lower than one would think, particularly if it wasn't at peak load much of the time(such as construction work).

I ought to design the PTO generator to be able to use the lowest engine speed that can provide the peak power need, and not worry about engine efficiency because the parasitic losses will likely overwhelm any engine efficiency effort.

Does that sound right?

I guess it also means that I should throttle back when sitting still for any length of time. I don't do that now(I normally run at ~75% of full speed all the time).

Thanks a million for your help.

Chris

By the way, I am going to include an overspeed, overvolt, disengaging clutch.

Thx.

 

[Soundguy]

I think you are being QUITE optimistic thinking that you will only need 15 pto hp to operate a 10KW generator. The general rule of thumb is ~2hp per KW generated. There is some 'fat' in that calc.. but it's a pretty safe.

My 12.5kw generator head specified it wanted a 25 PTO hp tractor ~minimum~.

The HP load the pto generator will consume will be proportional to it's electrical load. That is.. an unloaded 10kw genny not powering anything will take very little pto hp to just 'spin up'. If you load the genny by 50%.. assume that it will be using ~ 50% of it's rated input pto hp.

Also.. You need to keep pto rpm at a constant rate, based on the input needs of the pto generator. The power frequency is based on the pto gens # of poles and it's rpm.. that tells you what kind of gear reduction you will need.. etc. The more poles, the less head speed needed. Generally there is a step up gear box. For instance my head is a 3600rpm unit.. the gearbox is a 1:6.67 ratio step up from 540 pto rpm speed to the gennies 3500 rpm speed.

I think the overspeed / overvolt clutch is uh.. not needed. Your tractor has a governor.. set your throttle for the rpms you need.. and if the governor is in good working condition, it will work to keep the engine there...

Soundguy

That is interesting. What that means is, for example on a PTO generator, the parasitic losses are directly proportional to engine speed(assuming the supply pump is gear driven), and the optimimum engine speed for driving a 15 hp(10 KW) generator would be lower than one would think, particularly if it wasn't at peak load much of the time(such as construction work).

I ought to design the PTO generator to be able to use the lowest engine speed that can provide the peak power need, and not worry about engine efficiency because the parasitic losses will likely overwhelm any engine efficiency effort.

Does that sound right?

I guess it also means that I should throttle back when sitting still for any length of time. I don't do that now(I normally run at ~75% of full speed all the time).

Thanks a million for your help.

Chris

By the way, I am going to include an overspeed, overvolt, disengaging clutch.

Thx.

 

[dynasim]

Soundguy

The head I intend to install is a 10 KW peak, 7 KW continuous head. The peak power is(for my purposes) intended for starting electric motors, which means the peak load lasts for <2 seconds, and there is enough momentum stored in the engine to provide the last bit of peak power. I plan to tune the speed of the tractor to provide the 7 KW continuous electrical power without smoke, which will actually consume 12-13 HP of PTO power. Note that, if I were to run the tractor at full speed, more than 5 HP would be continuously consumed by the tractor just driving the internal hydraulic systems(it is an HST).

However, that was not what I meant when I said "15 hp(10 KW)". 10KW is 14.1 HP(by definition) or as close to 15 as I can come using mental math.

Soundguy: "I think the overspeed / overvolt clutch is uh.. not needed."

I do remote construction projects, and, as I said, would like to depower the driver(tractor) to minimize fuel use and wear by using a lower-than-peak engine RPM. The biggest problems are not so much the actual cost of the fuel, but the cost and inconvenience of transporting the fuel, as well as the tractor noise at full power. Therefore, I plan(after thinking about it a bit more, and discussing with various people) to run the PTO at ~400 rpm(final value yet to be determined).

If a generator that is running at its rated speed is hooked to any electronic device, and the speed of the generator is increased by 35%, catastrophic, perhaps dangerous, failure is likely. That event would occur simply by someone unconciously putting the tractor to full throttle. It is unlikely that anyone would sell me insurance against such an event for $75(the material cost of a clutch system).

The overspeed / overvolt clutch is needed in the situation I described.

I forgot the uh..

Thanks for your feedback. I am learning, and will attempt to make my writing more clear.

Chris

P.S. This discussion is a prime illustration of why U.S.A. consumed tractors do not have the PTO "energy saver" option.

 

[kensfarm]

Have you thought of using a heavy flywheel.. like they have on square balers to store energy for the "peaks"?

 

[dynasim]

That is a good idea and amenable to what I am thinking. Thanks

Chris

 

[Soundguy]

I still think the 14hp/10kw number is just not going to be realized unless you have divine permission and assistance. Most sources i see give a generous quote of 2hp consumed per generated kw.

I know.. i know.. your numbers on paper work.. but that isn't real life. If everything worke dlike it did on paper.. then the titanic wouldn't have cost white star lines so much business that day...

The genny and coupling will also introduce inherent ineficiencies that will effect your 'perfect scenerio' hp calculation.

I still don't see the need for the emergency fandago disconnect. Your example of accidentially increasing throttle to max and getting 35% more rpms.. is an example of extreme paranoid failure study.

For instance.. If a terrorist comes to my house to blow himself up tonight.. i don't need to worry about collecting social security when i get older... Guess what.. i aint quitting my job. Your scenerio is the same as if you had a 540 pto gen setup and some boob climbe dup there and ran the throttle up to max. On my 8n I think yuo can spin the pto upwards of 700 rpm with the engine zinging...

In the end.. it's your money and time. If yuo just want to do it to do it.. go for it. My opinion is that you will have way more time and a factor of money involved vs just buying a premade 7kw pto genny...

An electric clutch? Way easier ways to limit overvoltage using a comparitor and some simple switching circuitry to brak the electrical connections in the event of 'x' over voltage. Could probably rig it to kill the fuel solenoid onthe tractor too.

As for ecomony pto.. Hmm... I'm pretty sure I have seen an epto on some tractor over her.. I.E. one that can hit proper pto rpm.. but at a reduced hp output due to a different engine speed.

Course there is always the 1000 rpm pto option.. then just run her at half speed. A couple of my tractors hav that option just by swapping a pto shaft...

The amount of fuel you haul will be based on your consumption. I think you will find that fuel consumption will be based more on the amount of work you are doing, vs the rpm you are running. I.E. if you are generating 7kw of power.. then you will be using that equivalent amount of fuel.. don't matter if your pto is turning 400 rpm.. or 540.. the fuel needed to generate that power will be used.

Sure.. ya might burn a hair more with extra engine rpm just due to drag and ineficience.. but my bet is that the difference could be measured with a thimbol. Here's why i think that. I've mowed my pasture both with my 10' mower and 15' mower, and use dmy Nh 7610s and ford 5000 on the 10' mower. Here is what I have found. The 10ac i cut takes 5 gallons to do it... Don't matter if it is with my 70 hp ford 5000 on a 10' mower taking 3 hours... Or with my 95 hp 7610s and 10' mower, taking 3 hours. or with my 95 hp 7610s and 15' mower taking 2 hours... It still takes me that same 5g of fuel to do that set amount of work. I was kinda surprised that the 7610s didn't really burn any more fuel than the 5000 untill i realized that both were pretty much only buring enough fuel to get the job done.. only difference was the 5000 was working closer to max output than the 7610s was.. no difference inthe end result.. a mowed pasture, and 5g less fuel.

Have fun. i sometimes build things that i can buy cheaper and easier.. just because I want to do it.

Soundguy

Soundguy

The head I intend to install is a 10 KW peak, 7 KW continuous head. The peak power is(for my purposes) intended for starting electric motors, which means the peak load lasts for <2 seconds, and there is enough momentum stored in the engine to provide the last bit of peak power. I plan to tune the speed of the tractor to provide the 7 KW continuous electrical power without smoke, which will actually consume 12-13 HP of PTO power. Note that, if I were to run the tractor at full speed, more than 5 HP would be continuously consumed by the tractor just driving the internal hydraulic systems(it is an HST).

However, that was not what I meant when I said "15 hp(10 KW)". 10KW is 14.1 HP(by definition) or as close to 15 as I can come using mental math.



I do remote construction projects, and, as I said, would like to depower the driver(tractor) to minimize fuel use and wear by using a lower-than-peak engine RPM. The biggest problems are not so much the actual cost of the fuel, but the cost and inconvenience of transporting the fuel, as well as the tractor noise at full power. Therefore, I plan(after thinking about it a bit more, and discussing with various people) to run the PTO at ~400 rpm(final value yet to be determined).

If a generator that is running at its rated speed is hooked to any electronic device, and the speed of the generator is increased by 35%, catastrophic, perhaps dangerous, failure is likely. That event would occur simply by someone unconciously putting the tractor to full throttle. It is unlikely that anyone would sell me insurance against such an event for $75(the material cost of a clutch system).

The overspeed / overvolt clutch is needed in the situation I described.

I forgot the uh..

Thanks for your feedback. I am learning, and will attempt to make my writing more clear.

Chris

P.S. This discussion is a prime illustration of why U.S.A. consumed tractors do not have the PTO "energy saver" option.