Kifco T40x1320 - Two Axle 380,601 - Present Operator Manual - Manual (Page 21)

P/N 19302460 Copyright © April 2012 by Kifco ® Inc.
Start Up & Operation
Speed Compensation
Speed compensation is necessary for uniform application of water. The buildup of tube on the spool gives the
spool a larger effective circumference with each layer. With a constant speed of rotation, each layer of tube
on the spool makes a significant increase in the rate of sprinkler cart retraction speed during the irrigation run.
From the beginning of the irrigation run to the end of the run the typical speed increase of a hard-hose travel-
er is about 40%. This means that without speed compensation, if you set the travel speed to apply 1 inch of
water at the beginning of the run, you will get only 0.6 inches at the end of the run. On the average, the depth
is only 0.8 inches. This level of uniformity is unacceptable in most cases.
To better manage the uniformity of application, the Water-Reels are equipped with a speed compensator.
The compensator slows the rotation of the spool at approximately the same rate that the tube builds up on
the spool so the velocity of the incoming tube stays relatively constant throughout the irrigation cycle.
The compensation system monitors the diameter of the spool by use of a bar that rides on the tube and slows
the drive system to offset the increase in the circumference of the spool. The bar is attached mechanically to
the turbine motor or to the throttle of an engine drive system.
For Cruise Control equipped machines, the Cruise Control electronically compensates the rotation of the
spool. The Cruise Control knows the size of the Water-Reel it is controlling and knows how much tube is on
the spool. It then calculates the diameter of the spool and adjusts the rotational speed accordingly. The bar
that rides on the tube is not used for speed compensation. It is used for shut-off in the event of a mis-wrap or
when the sprinkler cart reaches the machine.
The compensator systems will maintain a reasonably constant sprinkler cart retraction speed throughout the
run.
See the “Maintenance & Adjustments” section in this manual for more information about adjusting the tur-
bine or engine compensators.
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