Thruster development allows ROVs to go electric

Soil Machine Dynamics Ltd (SMD), an advanced global supplier of Subsea equipment, was faced with the challenge of moving to an all-electric version of its Remote Operating Vehicles (ROV) to reduce environmental impact, improve reliability and performance whilst maintaining longevity, stability and consistency.

Magnomatics was asked by SMD to design, build a prototype and test a high-performance, electric version of its existing Hydraulic Thruster unit. The EV ROV Electric Thruster, developed incorporated state-of-the-art Magnetic Gear technology, increasing torque density over the existing hydraulic unit whilst maintaining reliability and durability.

The SMD and Magnomatics design teams together worked closely to outline the challenging specification and then a roadmap to turn this into reality through detailed design, analysis, prototyping and testing. This resulted in the first EV ROV on the market, exhibited at the Offshore Europe Expo’ in September 2019, only a year after the project started.

The SMD Thruster project was challenging on a number of fronts not least being the design for the smallest machine envelope, with the highest torque and Prop Curve response. Magnomatics’ engineers managed to fulfil the customer’s requirements and deliver a full set of prototypes.

The SMD Thruster units have a separate magnetic gear coupled to a high-performance permanent magnet motor. The magnetic gear comprises a high-tech bonded composite metal structure and close tolerance running clearances. To achieve the required tight space restrictions, the Thruster unit’s internal compactness provided additional challenges to the build team. Finally, the whole internal structure had to be designed to perform seamlessly in oil and be pressure compensated in service to operate at an incredible depth of 6000m.

For underwater ROVs the technology is exclusively available from SMD and Magnomatics is now actively looking for other applications for surface marine applications. Magnomatics is also setting up manufacturing facilities to make small to medium volume production for electrical machines such as this.

By Jake Frith