The growth of electric propulsion in shipping is continuing unabated. As manufacturers of these propulsion engines are increasingly busy, they are seeking out system partners to prefabricate components of their products, such as the magnet rotor. However, the bar is set high. The system partner must possess superior knowledge and technology in order to be able to meet the engine manufacturer’s stringent requirements.
Increasingly a system
partner for electric
Maarten de Bekker | Product Group Manager
“for complicated magnet technology they call on us”
Bakker Magnetics in Sciencepark Eindhoven is seeing demand from the marine sector rising. This Dutch high-tech company has been around more than 50 years and specialises in the manufacture and engineering of permanent magnets and PM assemblies. Magnets are at the core of electric propulsion systems for professional shipping and recreational vessels, meaning Bakker notices any growth in this market immediately. According to Maarten de Bekker, Group Manager of Bakker Magnetics’ Magnetic Technology & Assemblies division: ‘There are quite a number of medium to small producers of electric engines for smaller professional and recreational vessels. They can’t be expected to have all the knowledge in house, and for complicated magnet technology they call on us.
“We specialise in optimising the magnet assembly, so that the very best performance and maximum longevity are achieved“
The growth signals from this market are abundantly clear. Electric propulsions systems for large freight and cruise ships are built by only a handful of multinational manufacturers. Although they have the magnet technology in house, there is also an increasing demand from that market, primarily to facilitate these major manufactures. We take magnet-assembly construction and optimisation out of their hands, so that they can concentrate on their core competencies.
It makes sense that more and more vessels have electric propulsion, says Maarten: ‘Mainly because such engines are quiet, meaning you can even berth in port at night. Another benefit is the direct propulsion: put power into it and you’ve got torque straight away, even at low rotational speeds. You don’t need a large engine room with gearboxes, either. What’s more, the large engines fitted under a cruise ship, for instance, can rotate 360 degrees, meaning a large ship like that is still relatively easy to manoeuvre. And then of course there’s the sustainability aspect, since electric propulsion doesn’t require diesel.’ Because electric engines still have a limited range, the majority of large ships use a hybrid system: electric propulsion for ports and short voyages, and a diesel engine for longer distances. ‘We’re also seeing this in aviation: a jet engine for the flight and an electric engine for taxiing. As technology advances, the more important electric propulsion is becoming, and thus also its core: magnet technology,’ explains Maarten.
“We can offer major engine manufacturers the external support they increasingly request from the market“
Magnet technology is crucial for an electric propulsion system’s performance. ‘This is where an engine manufacturer can really make a difference’, says Maarten. ‘We specialise in optimising the magnet assembly, so that the very best performance and maximum longevity are achieved. It involves a whole range of factors, including, of course, the magnet material itself. Our joint venture in China allows us to produce the highest quality magnets in any form and grade, to order. This secure grip on production is essential for consistent quality. For instance, flux constancy is extremely important for submarines and frigates in order to create a vibration-free and therefore ultra-silent engine. That constancy is of course determined by the design, but also by the consistent quality of the magnet material. We’re able to offer clients certainty in this respect. Another factor is the immense strength of the magnets applied in large electric marine engines. For example, we use ultra-powerful 1.4 Telsa neodymium super magnets, which have to be glued or mounted with customised tooling and the utmost precision in a highly controlled and safe manner, to a complex bow-thruster rotor. This is an extreme specialism, just like the design: we like to provide our input in this respect, too. Although a Halbach configuration is more expensive, for instance, it provides greater flux density. What is the decisive factor? And: what is the ideal positioning of the magnets to have the engine achieve optimum performance? Or the best marine coating for protecting the magnets from corrosion? Our engineers calculate this precisely, too. We optimise the magnet rotor’s operation using all that expertise, resulting in significantly higher engine efficiency with greater longevity and minimum maintenance. And that makes a real difference for clients.’ says Maarten.
A recent project proved Bakker Magnetics is not too small for big shipping. Despite one the world’s largest manufacturers of electrical marine propulsions having high-quality magnet technology in house, it outsourced magnet-module production to Bakker Magnetics. ‘A prestigious order, that might well be a prelude to further cooperation’, says Maarten. ‘It involved electric POD engines for under a cruise ship. Each engine contains a huge rotor with around 70 magnet modules, with nine powerful magnets positioned and enclosed in each one. We produced the magnets in China and assembled the modules here in the Netherlands in a special production line. Due to the immense forces, this was once again a process that had to be performed with the utmost in terms of precision and safety. Errors are simply not an option, ever.’
“Each engine contains a huge rotor with around 70 magnet modules, with nine powerful magnets positioned and enclosed in each one“
According to Maarten, the project clearly demonstrated that Bakker Magnetics can handle large-scale marine projects. ‘We can offer major engine manufacturers the external support they increasingly request from the market. They don’t have to worry about that. We also provide smaller manufacturers with full assistance. And that’s not all. Even with a sizable project such as this, with all the requirements and complexity involved, the client complemented us on our flexibility and approachability. And this is actually what we’re happiest about. After all, at Bakker Magnetics, while we aim to be specialist with extensive knowledge and experience, we think it’s just as important to take on challenges and to experience the intensity of each phase of the process, together with clients. Celebrating successes together. This is why we want to be a system partner.’