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Floating barges in Nigeria have achieved massive energy savings, greatly improved
control and virtually eliminated maintenance costs thanks to an integrated control
system using Optidrive
Plus 3GVvariable speed drives.
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The floating barges use winches to haul the vessel and to control the spud palls,
the anchoring system used on this type of river barge. Known as spud barges these
are riverboats that are most commonly used as work barges, or as a loading or unloading
platform.
In this application four spud pall winches were required to provide a hauling force
up to 20,000 Kg and a holding force up to 30,000 Kg.
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Each winch was required to have an integrated control system capable of providing
reliable motor control in this high torque, harsh environment.
The solution was provided by Marotechniek BV of the Netherlands (www.marotechniek.nl),
a young and dynamic company founded by Martin Bossenbroek and Rob Molenaar who between
them offer more than 20 years experience in winches, mechanical and electric drive
systems for the marine and dredging industry.
Marotechniek manufactured, installed and tested the four planetary winch systems
with switchboxes on each winch using a 37kW power output
Optidrive Plus 3GV unit. These units were supplied by
Hiflex Automatiseringstechniek B.V. (www.hiflex.nl), the Invertek Drives Sales Partner
in the Netherlands.
This resultant system provides a highly superior solution to alternative approaches
using either hydraulic or direct on-line (DOL) control. Using Optidrive to control
the winch not only provides vastly improved speed control but also eliminates the
high maintenance costs associated with hydraulic systems.
In addition, the
Optidrive Plus 3GV control system requires a smaller generator
than hydraulic alternatives and hence provides large energy savings. The Optidrive
system also lowers installation costs by eliminating the need for a hydraulic power
pack, allowing the winch to be wired straight to the generator.
John van der Lugt, Sales Manager at Hiflex Automatiseringstechniek
B.V confirms:
"The innovative design features of the Optidrive range delivers significant performance
benefits and cost savings which ensure that it will remain the control system of
choice for the vast majority of winch applications"
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Technical Viewpoint
Justin Peters, Product Manager at Invertek Drives, describes the key technical issues arising in the marine winch AC drives application for floating barges in Nigeria..
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All Optidrive AC drives provide excellent performance in marine winch applications whether on ships, offshore platforms, or located within the harbour or dock area.
In this type of application a primary consideration is the level of exposure to the environment that the drive will be required to withstand, particularly if this exposure involves salt water. The different IP ratings offered with Optidrive allows the correct level of drive enclosure to be chosen for each application, ensuring reliable protection of the Optidrive electrical circuitry and connections even in highly corrosive environments such as these.
An integrated brake chopper is available for the majority of Optidrive products and is a feature available on all Optidrive models commonly specified for winch applications. In winching and dredging applications, where regeneration of braking energy is frequently required, this feature ensures simple and fast commissioning of the Optidrive. With this integrated braking resistor mounted directly to the standard Optidrive heat-sink, avoiding any requirement for a dedicated heat dissipater, the Optidrive continues to be one of the most compact units available in its class.
A key benefit of the Optidrive Plus 3GV in winch applications is the sensor-less vector performance that provides up to 200% torque down to zero speed. This allows the drive to operate in open loop without the need of an encoder, a major advantage in harsh marine environments where the costs of installing and protecting an encoder to ensure reliable performance can be very high.
The Optidrive provides highly accurate control of mechanical winch brake release and re-engagement through an integral relay output.
Compared to hydraulic winch systems the
use of an Optidrive can provide a more reliable solution with an easy to use
interface, less maintenance and often significant energy savings. Typically a
hydraulic system can require 25% more electrical power than an equivalent AC
drive and motor solution, primarily due to losses in hydraulic pump and
distribution systems. A hydraulic system also requires a regular maintenance
program that greatly increases the running costs. This maintenance cost can be
effectively eliminated through the use of an Optidrive operating an AC induction
motor. The highly efficient Optidrive range is therefore able to deliver major
costs savings compared to most hydraulic winching systems
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