On Mon, 23 Jul 2007 18:52:49 GMT, "Karl Townsend"
wrote:


You sure about the 10 lbf-ft from the turbine? That seems like a lot
but I have no experience with irrigation systems.

Pure guess, and on the high side. I plan on measuring force to pull the hose
at the PTO/hand crank shaft. And the exact gear reduction the system has
today. Makes sense to not re-use the existing gear reduction setup. Then I
could look for a DC gear motor. This should be way more efficient.

Why do you think so? One way or another, the motor speed must be
matched to the load speed regardless of who sold the gears. Some
gear trains are more efficient than others, though. For high
reductions, worm gears tend to be more efficient than trains of spur
gears because it takes fewer gears to achieve the same ratio.

I know that Lorenz Mfg. in Benson uses some Boston worm gear drives,
don't know if they'd sell ya one or not. They make electric winches
among other things. Also farm machinery.

The traveler is close to the reel today. I'll measure tomorrow when a full
length of hose is out. The place I'll set it out is also an uphill lie, so I
can get max. force. I'll just have a static torque wench number, moving
force will be lower.

Might be helpful to know the ratio (if any) between PTO/handcrank and
hose reel, or (perhaps better) what rev rate of PTO/crank results in
hose retreival of 50 ft/hr.