“There’s a global trend towards larger-scale plants, with the capacity of the individual processing equipment increasing as well,” says Ms Karita Forss of ABB’s high voltage induction motor product management. “Higher output motors are needed to drive the bigger machines, and our new flameproof motor will be ideal for these applications.”
With the new motor, ABB’s high voltage flameproof range is extremely broad: from 160 kW to 8 MW. These motors deliver a number of benefits which make life easier for the user. No purging is needed before starting, and no pressurisation system or inert gas is required. There is no thermal limitation for the ‘te’ time, and no need for a system test in variable-speed drive (VSD) applications – individual certification is not required. The motor is designed for low vibration running, which helps to increase reliability and improve the overall lifetime. Reduced maintenance requirements lower the plant operator’s cost of ownership.
Designing higher power motors to meet the requirements of flameproof protection (Ex d) involves considerable technical challenges. The main focuses of development were on optimising internal clearances, the labyrinth seals and enclosure. Advanced FEM (finite element method) techniques were applied to ensure that the new labyrinth seal design and thicker enclosure meet rigorous safety demands and provide sufficient robustness. Full compliance with all requirements was confirmed by an extensive program of testing. Both ATEX and IECEx certifications are available.
The motors are intended for fixed speed applications from 333 rpm (18 poles) to 3,000 rpm (2 poles), with 20-pole motors also available. They can be VSD fed. Operating voltages are 3 to 11 kV, 50 Hz or 60 Hz. The motors are tube cooled (IC511 or IC516) and can be supplied for either horizontal or vertical mounting.