Bearings for Cement Manufacturing

Large electrical machines have been used in the cement industry since the turn of the century. As cement production has become more complex, so has the equipment and automation systems that support the manufacturing processes. Electrical motors form the backbone of most of the processes involved in cement manufacturing plant such as kilns, crushers, ID fans, separators and cooler fans etc. Reliability of electric motors is important factor for the production and manufacturing of cement. Motor manufacturers serving cement industry are often faced with challenging tasks of designing motors suitable for various operating conditions and requirement which is not only reliable but also cost effective. Out of the several factors which may cause motor failure and reliability issues in cement plant, one of the most frustrating and involving is bearing failure. Although the cost of bearings is a small part of the motor its failure may cause costly equipment damage and expensive downtime. It is not uncommon for a motor bearing to operate fine during normal operation but fail during turning gear application on ID Fans. A fan ID drive may be required to operate a de-energized motor rotor at speeds as low as 50 rpm during turning gear applications which may lasts up to several hours. Sleeve bearing electric motors operating at low speed, such as during turning gear operations, require careful attention on bearing design for reliable operations. Sometimes bearings can be less forgiving at lower speeds than at higher operating speeds. A good understanding of various operating and ambient conditions, along with possible failure modes, helps the designer to design reliable bearings. Good design along with regular preventive maintenance practices can lead to longer bearing and motor life.