The Manchester Ship Canal Company has reduced maintenance costs for its dock gates at the Queen Elizabeth II Oil Dock, by switching from a two speed motor control arrangement to variable speed control, using Eurotherm Drives’ sensorless vector inverters.
The two lock gates forming the entrance to the dock are operated in sequence, allowing shipping to safely negotiate the passage from dock to river or vice versa. The lock gates are pulled open and shut from two winch houses located at either end of the lock. The winches are driven by hydraulic variable flow pumps which are controlled by movable swash plates.
The existing control for the swash plates was via a fixed speed motor, with associated electrical switchgear. Recognising the time had come to update the control system, Manchester Ship Canal installed a variable speed solution at Queen Elizabeth Dock built around Series 605 sensorless vector drives from Eurotherm Drives, under a choice of manual or PLC control.
The 60’s sensorless vector algorithium provides high torques at low speed, whilst allowing accelerations and decelerations to be precisely controlled, exactly matching the demands of oeprating the lock gate machinery. With the speed no longer fixed, the acceleration and deceleration of the gates can be optimised, while accurate control of the swash plates is achieved using limit switches, greatly reducing the possiblility of damage to the gates or the hauling machinery.
At the same time, the new solution has enabled all the old switchgear to be removed from the motor controls, so removing a drain on both time and resources, whilst giving the opportunity if replacing the two speed motor with a compact and cost effective standard one.
Available in powers from 0.75 to q5kW, series 605 drives combine sensorless vector power with a function block programming control scheme which provides flexibility in demanding applications, whilst ensuring many others can often be satisfied straight from the box.