NH Engineering & Design

[JimBinMI]

Bird,

No problems, just have several projects keeping me busy and two teenagers that also limit my time on the computer.

I read about the absence of Thomas and sent him a private message yesterday but no response yet.

Hope he's OK.

JimBinMI

 

[jinman]

Rat, the hi-lo (turtle-rabbit) electro-shift on the NHs is nothing more than energizing a solenoid to adjust the wobble plate in the hydraulic motor to 15º (lo) or 9º (hi). The motor works like a hydraulic pump in reverse, so the wobble plate position requires more or less fluid flow for rpm. The larger angle requires more fluid and produces more torque but lower speed (low range). The 9º angle produces more rpm for the amount of fluid and has less torque (hi range). As long as the solenoid will energize/de-energize, the ranges will shift. NH even made it easier by putting the solenoid on the outside of the case. If it fails, you can replace it without having to go inside the tranny. Ain't that neat?/w3tcompact/icons/cool.gif

JimI

 

[MODiesel]

Jinman:

I had read your description of the "turtle/rabbit" before & found the setup interesting.

Additionally, I climbed on a TS100 last weekend [no cab model -- odd, but very roomy], and it had a similar setup. Do you know if the Boomer setup was adopted from the larger tractors, or if it was introduced simultaneously across all models? I'm just wondering if it has a proven track record. Admittedly, NH made it easy to service, but I'm just curious.

Best Regards,
Jay

 

[jinman]

Jay, I'll have to plead ignorance on the rest of the NH line of tractors. The reason I know so much about my TC45D is that I bought the Repair Manual and it tells/shows the operation of the hydro tranny in great detail. As to long term reliability, I don't think this type of actuation has been used for very long on the NHs, but solenoid actuation has a long history of reliable operation for as long as I can remember (over 50 yr). Since most solenoid failures I have seen have been related to dirt inside the actuator cylinder, the fact that this is a sealed unit makes me think it will outlast the tractor. Now...there are the two switches which actuate the hi/lo ranges. We all know how "cantankerous" switches can be. Having redundancy there gives me a "warm fuzzy" for reliability. For the convenience of having that speed shift right on the FEL control, I'll take a little risk. After all, an all-metal seat is more reliable than a cushioned and upholstered one, but my butt likes the latter much more than the more reliable one. /w3tcompact/icons/wink.gif/w3tcompact/icons/smile.gif

JimI

 

[JATO_RaT]

Jim, does'nt the foot pedal also adjust the wobble plate? I'm trying to understand it. It sounds like a volume of fluid control rather then anything else. How do you like it? I know of no other company that does this. The closest I have seen is on CAT loaders. On the shuttle shift, they have the electricaly shiftable speeds 1, 2, and 3 simply by rotating the knob on the shaft. On many tractors the joy stick has the ability to disengage the clutch at the touch of a button so that high RPM's can get the pump running high for loader operation without moving forward or backward. NH has built in some nice features in their tractors. Rat...

 

[jinman]

Rat, I'm so glad you asked (the teacher in me is starting to show). When you depress the pedal, you are changing the wobble plate (NH calls it a "swashplate") on the pump instead of the motor. The hydro tranny has both a pump and a motor. By stepping on the pedal, you change the displacement of the pump by constantly varying the angle of its wobble plate. That variable output goes to the motor which has either hi-range angle or lo-range angle depending on the turtle/rabbit switch. The range I or II settings are even a different subject, since they are a physical gear change (meaning you have to stop the tractor to switch them). So two ranges on the hydro motor and two physical gear ranges give us four total ranges and constant varying speed within each of these ranges with the hydro pedal. Pretty slick!/w3tcompact/icons/cool.gif

Now for tomorrow, boys and girls, we will learn about forward and reverse....Oops sorry!/w3tcompact/icons/shocked.gif I have to switch back out of teacher mode here./w3tcompact/icons/blush.gif

Hope this helps, Rat./w3tcompact/icons/smile.gif

JimI