The Marine Aggregate Dredger CEMEX Go Innovation, currently under construction for CEMEX Marine UK, is fitted out with a submersed dredge pump, Damen said in its latest release.
“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.
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,” according to the official announcement.
This unique electric motor has been put to the test last week.
At a specialized 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, Damen said.
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.
The hopper dredger MAD3500 CEMEX Go Innovation 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.