Efficient, integrated vertical mill drive with high performance

Vertical mills are used, for example, to crush raw material and cement in the building materials industry or coal in coal preparation. The trend on the vertical mill market is toward larger production facilities.

The EMPP vertical mill enables drive applications involving power ratings from 500 kW to 15 MW to be operated with high plant availability. This is made possible by an integral, permanent-magnet synchronous motor supplied by a frequency converter. The omission of the bevel gear stage and the coupling enables the high forces to be optimally transferred, with the result that less complex components are required, which increases the efficiency of the mechanical system.

The grinding plate can be precisely controlled via the closed-loop speed control of the frequency converter. This means that although different grinding materials are involved, the grinding process becomes more even and can be optimized locally. Load surges resulting from short interruptions in the power supply are avoided by means of the electrical decoupling of the drive system, thus ruling out damage to the mechanical components. Rotary oscillations excited by the grinding process can be actively dampened via the drive. As it is often difficult to transport large components, from a certain size the EMPP drive can be delivered in two parts and assembled on site. The mill drive meets the requirements of the ATEX Directive that is of particular importance for coal mills with flammable coal dust.

The Siemens Industry Sector (Erlangen, Germany) is the worldwide leading supplier of environmentally friendly production, transportation, building and lighting technologies. With integrated automation technologies and comprehensive industry-specific solutions, Siemens increases the productivity, efficiency and flexibility of its customers in the fields of industry and infrastructure. The Sector consists of six divisions: Building Technologies, Drive Technologies, Industry Automation, Industry Solutions, Mobility and Osram. With around 207,000 employees worldwide (September 30), Siemens Industry achieved in fiscal year 2009 total sales of approximately €35 billion.

The Siemens Drive Technologies Division (Nuremberg, Germany) is the world's leading supplier of products and services for production machinery and machine tools. This includes standard products but also encompasses industry-specific control and drive solutions. Integrated technologies along the entire drive train with electrical and mechanical components offer highest potential to reduce energy consumption in industrial plants. The services provided by the Division include mechatronics support in addition to online services for web-based fault management and preventive maintenance. With around 36,000 employees worldwide (September 30), Siemens Drive Technologies achieved total sales of €7.5 billion in fiscal year 2009.

Reference Number: IDT2010032313e