"Karl Townsend" wrote in message
link.net...
I burned the bearings out on my drive turbine for the traveling irrigator.
To get by, I removed the turbine completely and I'm pulling hose in with
the tractor PTO.

I LEARNED SOMETHING! The turbine takes its power out of the water
pressure. Its reducing pressure to the sprinkler from 115 PSI to 100 PSI.
And the gun works WAY better at the higher pressure.

The power from the turbine is dinky. You twist it by hand to start it when
it stalls. I'm going to guess 10 ft lbs. It runs at maybe 500 RPM. There's
then a gear train that reduces the speed by maybe 500:1 to give high
torque to the bull gear driving the reel. This assembly pulls in a 3"
water hose at 50 feet per hour.

I'm wondering if a DC motor and deep cycle batteries would do this job.
This thing needs to be super reliable, it runs more than 120 hours a week.
Am I within the power range of a DC motor setup? I'd need at least 8 run
hours between recharging. What would be the best unit in terms of
efficiency?



I doubt it. It still takes a lot of power to pull in the hose- have you ever
cranked one by hand? I have.We sell lots of travelers and I've never heard
of a turbine bearing failure (We used to sell Kifco and switched to Micro
Rain a year ago).
FWIW- your 15 psi pressure drop is caused not only by the turbine, but also
the drag in the rest of the water circuit ( there is a lot of loss in all
that hose) and attempting to go above a water velocity of about 5 fps by
boosting pressure ( you can't boost flow) only makes things worse by
introducing turbulence in the system.

Why not rebuild the turbine and be done with it? It'll be super reliable and
run more than 120 hours a week no worries.

-Carl
--
The future isn't what it used to be.