"Karl Townsend" wrote in message
link.net...
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 don't know this for certain, but would be willing to wager that the
pressure loss is due more to lost flow through the turbine nozzle than to
lost "pressure". More'n likely, the oriface isn't large enough to swamp the
flow requirements of your spray nozzle. All this, IF it's a "full flow"
system, with the turbine in series with the sprinkler nozzle.

If that's all the case, then you might consider putting it in parallel, and
running a small "secondary" spray nozzle to exhaust the portion of water the
turbine uses.

I've always been on a well (residential), and have had nothing but bad luck
with water-motor drives at the pitifully low cut-in pressure on most well
pumps. They tend to stall when the water pressure starts to get low, and
don't start to spin again (if ever) until the pressure peaks again.

LLoyd