Feature Drives & motors A modern design
An integrated drive and control system featuring Control Techniques MP DC drives has helped modernise the Terminal de Contenedores de Yucatán container and cargo-handling terminal
Yucatán peninsula began operation in 2005, the two Panamax Starporter ship- to-shore cranes, manufactured by Star Iron & Steel of Tacoma, Washington State, USA, were already nearly thirty years old. During the next seven years, however, keeping the cranes operational was becoming difficult – despite being mechanically sound, they were in a poor electrical condition. Furthermore, finding replacement parts for the old DC drives was nearly impossible. To overcome the issue, Emerson
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Control Techniques proposed a new fully integrated drive and control system featuring its Mentor MP DC drive. David Asensio, project man- ager for Grub TCB of Spain, which owns the terminal, explained that being rugged and easy to maintain, this drive solution proved to be the best for the application. The control system encompasses
all the electrical equipment including low-voltage auxiliaries, DC drives, PLC, I/O, crane management system and MCC; plus new remote I/O and control stations, RF Ethernet-based remote diagnostics, and a modern rotating operator’s chair and consoles. A 120 amp Mentor MP was selected
for the hoist, which uses a 373kW motor rated at 50 tons and has a speed of 45/min. The 55kW trolley, with a speed of up to 120m/min and the 55kW boom with a maximum speed of 6m/min, share a 210 amp Mentor MP, which is switched between the two. The eight 14kW, 45m/min gantry motors have their duty shared between four 105 amp Mentor MP DC drives.
Increasing reliability Described as a reliable, flexible and powerful digital DC drive, the Mentor MP is designed to maximize motor per- formance, enhance system reliability and interface digitally with the latest control equipment using Ethernet and a wide range of industrial networks – making it suitable for modernising port cranes and equipment. Additional features of the range
include user-configurable functions – including master-slave management, electric shaft function, digital or analogue feedback and torque control –
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hen the Terminal de Contenedores de Yucatán – TCY – container and cargo- handling terminal in Mexico’s
that are arranged logically in different menus and preconfigured with default values to facilitate commissioning. The operational parameters can be selected and modified from the drive keypad or through the Windows-based software CTsoft. The SM-Application module is an easy plug-in second processor, capable of writing application specific programs without needing to use a PLC or stand alone controllers. It is programmed using SyPT, an IEC 1131 compliant programming tool incorpo- rating function blocks programming. The SM-Application modules of
the two drives, which operate the hoist- ing motors and connect via Control Techniques’ own high-speed network CT-net, use a load balancing function to control container hoisting and calculate the maximum lifting speed as a function of the load hooked to the spreader. With the spreader empty, the SM-Application modules enable movements at the maximum programmed speeds. Crane productivity is maximized by
using a series of bespoke basic, modular and open-ended software packages, developed by Control Techniques specifically for crane control. These are
The Mentor DC drive was selected, which offers a rugged and easy to maintain solution
programmed into the PLC and onboard SM-Application mod- ules, and connected via fieldbus, optimising movements in order to relieve the operator of these delicate and repetitive tasks. In addition, hoisting, trolley, boom and gantry movements are
all driven by DC motors that are controlled by means of Mentor MP digital drives connected via a Profibus network to a controlling PLC. Control Techniques also designed
the Crane Management System inte- grated into its basic software and enhanced with control modules for the maintenance guide and diagnostics. Operational at the various levels of automation, the software automatically signals events as they occur.
Control Techniques
www.ControlTechniques.com
The benefits of Pseudo Direct Drive technology W
hen an application demands high levels of continuous torque with minimal ripple and noise, the Pseudo Direct Drive (PDD) from Magnomatics can provide the solution.
Gearboxes are used in many applications to permit relatively high rotational speeds in electrical machines. By operating
at these higher speeds, the electromagnetic torque required from the machine is minimised, leading to lower electrical stresses, lower losses and smaller machines with a lower capital cost. The drawbacks normally associated with this type of system are the reduction in efficiency caused by the mechanical gear, additional system complexity, increased probability of failure and the use of fluids and lubricants which require regular maintenance and present a potential environmental risk. Magnetic gears offer the advantages of mechanical solutions while avoiding issues such as system reliability and the
need for regular maintenance. The benefits are further enhanced by the full mechanical and magnetic integration of the gear system within the central core of the electrical machine, resulting in an extremely compact unit. The resulting combination of magnetic gear and motor is referred to as a Pseudo Direct Drive (PDD). In it, a rotating
Section through a PDD
field in the outer stator is used to drive the inner high speed rotor. The interaction of the flux from this rotor with steel pole pieces and the outer static magnets results in a magnetic gear. With gear ratios typically between 5:1 and 15:1, this produces compact electrical machines with torque densities that exceed conventional technologies by up to 300%. The bearings apart, the PDD is lubricant free and there are no wearing parts. While mechanical gearboxes are over-rated to tolerate occasional excessive loads, repeated or excessive high load conditions will cause catastrophic failure. The magnetic gear is tolerant of excess loads and is designed to slip then re-engage once the torque is back within stated limits. Furthermore, the natural compliance, or elasticity, inherent in a magnetic gear provides a degree of torsional damping, resulting in a very smooth, low-noise drive (ripple <0.3%). A final benefit of the PDD is that it is highly efficient over a broad range of operating points. With power ratings ranging from a few watts up to 20MW, applications can be in a wide range of industries – from marine propulsion, renewable energy, hybrid and electric vehicles, to industrial and aerospace actuation.
www.magnomatics.com
Magnomatics Enter 220
Enter 221 JUNE 2013 Design Solutions
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