Combines Rotor drive power consumption

I guess I do not know how much power it takes to run the cvts but I do know after running 8010s and cvts since 04 I would not go back to belts so much nicer to run big heads with no more belt problems and rotor belts yes 8010s had a lot of growing pains till they got them figured out. And the new 70 series J.D. still run belts but they also have one size combine fits all 96-98 just turn up the power and raise the price! let see it took close to 20 years to copy the axial flow it will probably take them 15 for the cvts.

How much energy is lost to a CVT or worse yet a hydraulic drive rotorIJ Good question, see how large an oil cooler the combine has compared to a mechanical drive. The power going into the rotor drive comes out only two ways, motion or heat. If the oil cooler is huge compared to a mechanical drive, then there may be quite a bit of loss, if not, then their may not be much difference.

I'll take a stab at this one and say the reason that Deere uses a belt is because a belt is cheaper; it results in more parts sales for mother Deere; and they don't have to have anything better because they can still sell the STS despite it being a very poor design. The 70 series still runs a belt. That said, it doesn't mean that I'm 100% sold on CVT or hydraulic rotor drives either. A properly designed belt for the application will have the best efficiency, to be sure, and can last a very long time, again, if properly designed and matched to the application. There are pros and cons to each system.

Best I can remember from class, a belt drive will exceede 98% efficiency when adjusted and run properly and hycraulics are about 86% efficient.

Remember that for every right angle transfer of power (through a gear box, chain box, diff., transfer case, etc.) you'll lose on avg. 2%. For example, on an STS you have the main engine gear case out to the rotor drive gear box (2%) to run the VS belt; out to the shaft (2%) that goes down to the transfer case to the feeder house drive (2%) to the reverser gear box to drive (2%) the feeder house and head, for a total of 8% power loss. CVT's have always been notorious for being 85-90% efficient and since the AFX isn't a true stepless CVT it's going to be less efficient, probably around 80-85% efficient. Hydrostats are by far the worst but great for control, which leaves power shift and belt drives as the two top winners for most efficient. Power shift is going to be the top winner for its nearly 100% efficiency rating while belt drives are above 95% efficient. These are basic facts taught in most beginner drivetrain classes at trade schools and technology_engineering colleges.

Sounds to me that the extra power to drive a cvt is not a big deal. Myself, I like the idea of having reverse option on the rotor, especially in rice.

I would agree that all the advantages of the cvt drive outweigh the slight loss in effieiency.

Anyone here in the midwestIJ I read an interesting article yesterday saying there is a diesel shortage in this area until all the refineries are switched over to their seasonal winter fuel operating status. Is this trueIJ Fuel efficiency will be a major concideration in the future and the soothsayers are predicting natural drying will be the way of the future. Back to the original question. Belt drives are around 95 to 98% efficient and can be as low as 90 with an old belt that stretches. Hydraulic pumps or motors can achieve 90% and a pump_motor combo (hydrostat) is around 80%. Therefore on a 300 HP machine 1 to 2 gallons an hour can go to drive the drive system. I presume thats why industrial equipment and highway trucks dont use hydrostats

You should mention what belt drive power loss is 3-5%. From what I know about transmissions angle gear loses 1.5- 2% so 2% is max not average. There are some more things. For example max torque available thru belt and mechanical or hydrostatic. Max transfer ratio you may get from belt. And last but not least dimensions. Consider all those things together I and I believe you shall not even thing about the belt drive on the machines bigger then 400 hp.