Near Intersection of I-35 & I-90 Southern Mn. | I agree. The IVT that we have doesn't have a variable ratio between the Engine RPM and PTO speed (well except for 540 vs 1000). In order for the generator to be run at the correct RPM, the engine would need to run at a certain RPM.
Whether you had IVT or not the engine would use a certain amount of fuel to keep the PTO running at that speed. The normal engine controls would handle the fuel management.
There is a rotary switch on the dash on our 7830. The second position has a picture of a PTO on it. When the tractor is operating in this position it will reduce the ground speed to help keep the PTO running at a certain speed. For example, if you were chopping hay and the chopper started to pull down, the system would reduce the ground speed in an effort to reduce the load.
This has nothing to do with sationary work such as a blower or generator.
In positions three and four the system will reduce engine RPM to maintain a certain ground speed. In other words if you set a certain ground speed and engine speed, the system will reduce the engine RPM and increase the transmission ratio to achieve the desired ground speed with a lower engine speed.
My thinking is that the owners think that the PTO works that way too and thus should have improved fuel economy. I suppose something like that could be done with the PTO drive arrangement but such is not the case on our tractor anyway.
I believe some Deere tractors had an "E" position for economy for light PTO loads. This changed the engine ratio to PTO ratio so that the engine would be run at a lower RPM which might translate to fuel savings. This was not a variable design but just a different constant ratio.
I remember as a kid reading about the first Ford Select-O-Speeds. I believe there was a way to use the transmissions output to the PTO. The PTO ratio then depended on the gear that the tractor was in. This was sort of a ground drive equivalent and the PTO speed was directly proportional to the ground speed. I'm not sure what that would be used for. |
IVT and power outage
