Successful full performance test CEMEX dredge pump e-motor

The Marine Aggregate Dredger CEMEX Go Innovation, currently under construction for CEMEX Marine UK, is fitted out with a submersed dredge pump. This dredge pump is directly driven by an electric motor – and not an arbitrary one. As a first, the dredge pump drive is a permanent magnet 1,400 kW unit, that last week it underwent a large array of tests – passing them all effortlessly, Damen said in its release.

Submersed dredge pump drive
The hopper dredger is designed for mining marine aggregates at -55 m below sea level. The submersed Damen dredge pump is directly driven by a continuous electric motor – that is, without a gear box in between. Moreover, the electric motor forms an integral part of the trailing pipe structure. But the story does not end there: the air filled e-motor is of the Permanent Magnet type. And in addition to that, it usually functions at -25 m below the sea level, that is somewhere midway in the trailing suction pipe. This unique electric motor has been put to the test last week.

Performance test
At a specialised performance test facility not only the e-motor but the complete drive train - including the frequency converters - have been tested. During a full week of testing a large number of different tests have been performed. These included a full power test, an overspeed test at 120% of the nominal revolutions and a 130% torque test. All tests have been concluded satisfactorily.

The tests were closely monitored by the project team, including CEMEX representative, the supplier Marotechniek and the Damen project team. The CEMEX project manager Mark D.Williams said : “I was impressed with the quality of the equipment on test.” After a full week of testing, all gear will be shipped to the Netherlands shortly, where it will be fitted out with the dredge pump parts, and mounted into the trailing pipe system.

A technical feat
The 1,400 kW electric motor on test is the largest Permanent Magnet motor used in a submersed dredge pump drive to date. The air filled motor is smaller, lighter and more efficient than conventional asynchronous oil filled ones – with a staggering measured efficiency of 97% including friction of all bearings and mechanical-seal. The electric motor is controlled by a water cooled AFE drive. The electric motor has been designed in close cooperation between Marotechniek and Damen Dredging Equipment.

Background information
The hopper dredger MAD3500 CEMEX Go Innovation is currently under construction at the Damen Shipyard in Galati, Romania. The dredging equipment however is constructed by Damen Dredging Equipment in the Netherlands. The dredger will be used by CEMEX Marine UK to mine aggregates in the British Channel and North Sea. The innovative dredger has a number of special features, including the permanent magnet electric motor, which powers the dredge pump for mining aggregates at -55m.



Damen Shipyards Group
Damen Shipyards Group operates 36 shipbuilding and repair yards, employing 12,000 people worldwide. Damen has delivered more than 6,500 vessels in more than 100 countries and delivers around 175 vessels annually to customers worldwide. Based on its unique, standardised ship-design concept Damen is able to guarantee consistent quality.

Damen’s focus on standardisation, modular construction and keeping vessels in stock leads to short delivery times, low ‘total cost of ownership’, high resale values and reliable performance. Furthermore, Damen vessels are based on thorough R&D and proven technology.

Damen offers a wide range of products, including tugs, workboats, naval and patrol vessels, high speed craft, cargo vessels, dredgers, vessels for the offshore industry, ferries, pontoons and superyachts.

For nearly all vessel types Damen offers a broad range of services, including maintenance, spare parts delivery, training and the transfer of (shipbuilding) know-how. Damen also offers a variety of marine components, such as nozzles, rudders, winches, anchors, anchor chains and steel works.

Damen Shiprepair & Conversion (DSC) has a worldwide network of eighteen repair and conversion yards of which twelve are located in North West Europe. Facilities at the yards include more than 50 floating (and covered) drydocks, including the longest, 420 x 80 metres, and the widest, 405 x 90 metres, as well as slopes, ship lifts and indoor halls. Projects range from the smallest simple repairs through Class’ maintenance to complex refits and the complete conversion of large offshore structures. DSC completes around 1,300 repair and maintenance jobs annually, both at yards as well as in ports and during voyage.