Cable reeling system

Abstract

A cable reel system for use in conjunction with a mobile installation movable relative to a fixed base station and being connected to the fixed base station via a cable, the system comprising a reel on which the cable is stored, the reel being connected by a motor shaft to an AC motor which drives the reel via reduction means to pay-out cable whilst the mobile installation moves away from the base station and to reel-in cable whilst the mobile installation moves towards the base station, the reel system further comprising sensing means located adjacent said motor shaft and operable to provide a signal representative of the position of the motor shaft, and a controller, which receives the signal and calculates a torque demand signal, the controller further continually varying a stator current of the motor in response to cable paying-out or reeling-in operating conditions pertaining at a given instant by using the torque demand signal to calculate and supply phase currents to the motor to provide a required torque at the motor shaft for maintaining tension of the cable extending between the mobile installation and the fixed base station within a predetermined range of values.

Dependencies are inferred from the claim text.