Condition monitoring helps to keep plant availability high

E.ON Kernkraft in Germany is benefiting the FAG VibroCheck online condition monitoring system from FAG Industrial Services (F'IS), the maintenance and condition monitoring company within the Schaeffler Group. Since its initial implementation in 2004, FAG VibroCheck has on several occasions identified damage to bearings, imbalance in fans and unstable machinery at an early stage, thereby enabling the maintenance team to order the necessary spare parts and resources and to plan the replacement of the damaged part within the regular maintenance schedule or shift.

The FAG VibroCheck is suitable for condition monitoring of critical rotating machinery and components, such as gearboxes, bearings fans and pumps. Using selective frequency monitoring, the FAG VibroCheck automatically detects imbalance and misalignment in rotating plant and machinery, as well as damage to individual bearings and gears. Selective frequency monitoring enables even minor damage or defects to be detected at an early stage, since these cause an increase in the amplitude of the characteristic frequencies. FAG VibroCheck also uses demodulated signal analysis, as this is useful for monitoring shock pulses.

Up to 2048 measuring points can be monitored and the system can be easily integrated into a plant's existing systems. Remote monitoring is possible and alerts can be sent via email or SMS text message to the appropriate individual.

At E.ON Kernkraft, more than 200 separate measuring points on 90 electric motors, pumps and fans are being monitored by the FAG VibroCheck system, which provides maintenance managers with information on the condition of rolling bearings, gear sets, shafts and imbalanced rotors in fans and pumps. Although 12 staff at E.ON are trained to use the FAG VibroCheck system, the company also has a teleservice contract with F'IS, which includes the online remote monitoring of the plant and technical support by F'IS vibration monitoring specialists, who help to analyse and evaluate recorded data.

Bearing damage detected

For example, the FAG VibroCheck system at E.ON Kernkraft recently detected bearing damage in a pump at an early stage. This damage was then confirmed by visual inspection and the bearing replaced in a timely manner by the maintenance team. If left undetected, the bearing damage would have led to failure of the pump, resulting in a complete shutdown of the plant.

As a subsidiary of E.ON Energie, E.ON Kernkraft GmbH is a major contributor of electricity generation in Germany. The company operates six nuclear power stations in Bavaria, Lower Saxony and Schleswig-Holstein and is involved in a further five plants. The company employs around 2500 staff and generates a total annual output of 8500kW.

E.ON Kernkraft's Grafenrheinfeld nuclear power plant in Germany was commissioned in 1981. The pressurised water reactor is rated at 1275MW and is cooled by two, 143m high, natural draught cooling towers. The plant generates electricity for base load applications.

The working availability of the plant at this site has to be very high, at more than 90 per cent. This is not only because of safety reasons but also for efficient maintenance of plant and machinery. Failure of individual components or machines can cause costly secondary damage or shutdown of the complete plant and therefore result in more lost production.

For more information on F'IS products and services, visit www.schaeffler.co.uk.