Vertical mill drive solves surge problems

Paul Boughton
Siemens Industry Drive Technologies Division has launched a new Flender vertical mill drive that prevents load surges arising from short term power interruptions and optimises performance between drive and mill, enabling power ranges to be expanded to 15MW.

Reliability is also enhanced through a reduction in the number of components susceptible to faults. 

The EMPP (electrical motor and two planetary gears) vertical mill drive is an innovative drive concept, featuring a newly developed motor in which the gear housing is built in under the planetary gear. The power transmission features a permanent magnet synchronous motor with a highly efficient cooling system, and the drive is controlled by a frequency converter.  This ensures maximum running smoothness combined with optimum grinding results for varying operating conditions.

Vertical mills are commonly used to crush raw material and cement in the building materials or coal industries and trends are towards larger production facilities. The new units are available in power ratings from 500kW to 15MW, and above a certain size, units can be delivered in two parts and assembled on site.

The footprint of the new drive means that no laborious retrofitting is necessary. This new mill drive meets the requirements of the ATEX Directive – of particular importance for coal mills with flammable coal dust.

The Siemens Drive Technologies Division is the world’s leading supplier of products and services for production machinery and machine tools. Integrated technologies along the entire drive train combining electrical and mechanical components offer the highest potential to reduce energy consumption in industrial plants.

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