Special permanent magnet generator with explosion protection

TÜV Nord grants Huebner generator IEC 60079-0 /-15 Ex certification.

Hübner Giessen is taking another step in its mission to develop custom solutions for specific needs. The provider of drive and encoder technology now offers its DSG P 112.14-6 Ex three-phase synchronous generator with IECEx certification for explosion protection. This certificate confirms that the generator meets international standards for technical work on explosion-proof products and can be used in explosive atmospheres. The device does not generate sparks, reducing the risk of explosions in atmospheres with free gases and preventing production losses and injury due to explosions at the site of the generator’s use.

TÜV Nord in Hanover, Germany – one of the world’s most respected IECEx certification authorities – has examined the generator’s explosion-proof qualities. It has confirmed that the Hübner generator passed the type verification and tests on test devices. A TÜV Nord audit has additionally shown that the company has an effective quality management system in place. “This internationally recognised certification does not yet exist for permanent magnet generators, so this is a real breakthrough,” according to Professor Ewald Ohl, Head of Energy and Drive Systems at Hübner Giessen.

Ex-protected generator for gas liquefaction plants

The Ex-protected Hübner generator has now been used for the first time as a pilot exciter at a gas liquefaction plant. In gas liquefaction, the expansion of gas under pressure creates surplus energy as a by-product. This is fed into a gas-expansion turbine and a power generator to electrify the plant instead of emitting it into the environment. The pilot exciter from Johannes Hübner Giessen is used in this setting in black starts, an emergency start, to restore power following complete outages of the main electricity supply. 

Through its rotating magnetic field, the pilot exciter induces voltage in the turbine of the main exciter, which supplies the power generator with the necessary exciter field and ensures that the emergency power system remains functional. 

The main exciter will lose its remanence (remanent magnetisation) if a plant is idle for a longer period of time. As a result, the power generator will not have an exciter field during a complete outage of the main electricity supply and will not work properly. When this happens, a permanent magnet pilot exciter generator is needed. With every rotation of the turbine, the pilot exciter generates voltage and supplies the main exciter with a new magnetisation curve. By doing so, the pilot exciter guarantees the availability of the main exciter and ensures the power supply at all times. 

Hübner has developed the generator especially for this application. Thanks to this new Ex-protected version, it can be used in gas liquefaction plants for the very first time. In addition, the DSGP 112.14-6 Ex has been coated with RAL 7035 worldwide, a seawater-resistant coating that makes it perfect for use in coastal locations. It has an ingress protection rating of IP 55 and Ex nA IIB T3 Gc explosion protection.