Ready for the boat: Drive controllers are now marine-certified
KEB COMBIVERT F6 drives for offshore applications and ships
The COMBIVERT F6 drive controllers from KEB Automation have successfully received marine certification. With this, the systems provider of automation and drive technology has created a drive solution optimised for the requirements of ships, offshore applications, speedboats and similar vessels. A total of four relevant certificates have been issued for the F6 Drive Controllers. This was preceded by extensive testing, during which the devices were subjected to various demanding environmental conditions, amongst other things.
It’s now time for KEB’s COMBIVERT F6 Drives to cast off: The frequency inverters in the “Application” and “Pro” variants are available for use in various marine applications with effect from now. Customers can choose between an air-cooled built-in or push-through variant, or a liquid-cooled push-through variant. The drives cover a power range from 2.2 to 450 kW and can be combined with KEB’s standard filters and chokes. On board, the F6 drives are used, for example, to operate propulsion systems, auxiliary motors or artificial networks.
There are currently four certifications
Bureau Veritas (BV) has classified their use on all steel ships in environmental category EC31. This means, specifically, that the equipment has been tested and approved for use on the navigation bridge and on open decks of ships. The DNV certification applies to ships, offshore installations, and high-speed and light craft. The drives are certified by Lloyd’s Register (LR) for maritime, offshore and industrial applications for use in environmental categories ENV1, ENV2 and ENV3 (use in general power distribution areas) as defined in LR’s Type Approval System, Test Specification No. 1 – 2024. Finally, the drives are also certified for use on vessels and offshore installations classified by ABS (in accordance with the listed ABS rules and international standards). However, it is not only the COMBIVERT F6 drive controllers that have been certified, but also the underlying production process at KEB and BV, DNV and LR have therefore carried out a comprehensive factory audit.
Solution for harsh environmental conditions
“Maritime applications generally involve particularly demanding environmental conditions for drive technology. Our certified drives are therefore optimised for temperature ranges of five to 45 degrees Celsius and relative humidity of five to 85 per cent. The drives have protection class IP20 and are designed for installation in control cabinets,” says Jean-Paul Rebelo, project leader at KEB France. Furthermore, the units can also be operated at temperatures between 45 and 55 degrees Celsius, with a power reduction of five per cent per degree Celsius. The inlet temperature of the cooling medium is between five and 45 degrees Celsius for the air-cooled version and between five and 40 degrees Celsius for liquid-cooled versions.
Extensive testing
Before the certificates were issued, the drive controllers were subjected to numerous tests, which can be categorised into environmental tests, immunity tests (or tests for electromagnetic compatibility) and electromagnetic emission tests. As part of the environmental testing, the vibration loads, insulation resistance and the behaviour of the drives at a test voltage of 2,000 V were assessed, amongst other things. It was also demonstrated that operating the units in cold and dry heat conditions does not cause any damage. Damp heat is also one of the conditions under which the drives operate. They were therefore exposed to temperatures of up to 55 degrees Celsius at over 95 per cent relative humidity in two cycles (each lasting 24 hours).
The electromagnetic compatibility testing included testing for fluctuations in the power supply, immunity to conducted low-frequency interference, electrostatic discharges and electrical transients. The tests also included a power supply failure test. The relevant test procedure specified three interruptions within five minutes. For equipment that requires a start-up procedure, an additional interruption had to be carried out during the start-up process. A 30-second pause was specified between switching off and switching on again. As part of the electromagnetic emissions test, particular attention was paid to radiated and conducted emissions.
The drive package from a single source
As a system provider, KEB Automation not only supplies the appropriate frequency inverters, but also offers users the opportunity to obtain complete drive solutions from a single source. On ships and offshore installations, in particular, combining these with the appropriate motors is highly recommended. In applications that have already been implemented, the integration with KEB’s asynchronous or synchronous reluctance motors, amongst other things, has proved to be a powerful combination.
“Whether it’s a turbo compressor or a drive control system – every marine application is different and has very specific requirements for drive design. We are delighted that, with the certified COMBIVERT F6 Drives, we can offer a high-performance solution that is precisely tailored to the needs of the marine industry,” says Jean-Paul Rebelo.