Patent ID: 9661808
Date: 2017-05-30
CPC Classifications: A01G

Claim:
1. An irrigation system having a movement direction over a ground surface of a field, the irrigation system comprising: at least one intermediate span and at least one end span; a tower structure configured to support each span above a ground surface; and a dual-controller drive assembly of a tower structure having: (a) at least one wheel configured to contact a ground surface below the irrigation system; (b) at least one span motor configured to drive at least one wheel so as to propel the tower structure over the ground surface; (c) a drive controller unit configured to control power supplied to the span motor, the drive controller unit including a fixed-speed drive controller and a variable-speed drive controller; and (d) at least one selector switch configured to select between: (i) a first operational mode of the drive assembly characterized by the fixed-speed drive controller controlling power supplied to the motor to operate the motor and the wheel at a fixed speed to maintain a uniform movement speed of the tower structure across the ground surface; and (ii) a second operational mode characterized by the variable-speed drive controller controlling power supplied to the motor to operate the motor and the wheel at a variable speed to vary the movement speed of the tower structure across the ground surface.