Expertise in Technology and Service for Turbines The Company

Expertise through knowledge and experience

FAG Kugelfischer is the pioneer of the For over 30 years, INA and FAG have Monitoring systems, lubricants, mounting rolling bearing industry. In 1883, Friedrich designed and produced bearing arrange- and maintenance tools. In this way, Fischer designed a ball mill that was the ments for wind turbines. Within Schaeffler Schaeffler Group Industrial helps to historic start of the rolling bearing industry. Group Industrial, the specialists from achieve low operating costs for wind INA began its path to success in 1949 the business unit “” work turbines. with the development of the needle closely with designers, manufacturers Core skills roller and cage assembly by Dr. Georg and operators of wind turbines. This Schaeffler – a stroke of genius that has resulted in unbeatable know-how: • Wide range of application-specific helped the needle roller bearing to make as early as the concept phase, detailed bearing designs, intensive ongoing its breakthrough in industry. Schaeffler attention is paid to customer require- product development

Group Industrial with its two strong ments. Bearing selection and documen- • Soundly-based consultancy by brands, INA and FAG, today has not only tation are backed up by sophisticated experienced engineers a high performance portfolio in rolling calculation methods. Products developed • Optimum application of customer bearings but also, through joint research to a mature technical level are optimally requirements and development activities, products matched to the particular task. The range and services of unsurpassed quality. is intelligently rounded off by Condition • State of the art calculation programs such as Bearinx® for optimum product selection

• Comprehensive service for operation including detailed analyses

• Condition Monitoring system recognized by Allianz Insurance

• General and customer-specific training programs

• Worldwide adherence to quality and environmental policy (ISO 9000/ QS 9000, ISO/TS 16949:2002, ISO 14001)

 From a single source A comprehensive range for wind turbines

Rotor shaft: Proven, high The ideal bearing arrangement Extended bearing service life in Wind tracking and blade adjust- performance bearing concepts for any gearbox generators by means of current ment: Bearing arrangements insulation ensure long term mobility

(Picture: DeWind GmbH)

Remote monitoring and Mounting and maintenance Rolling bearing lubrication – Concentrated knowledge for diagnosis critical for service life expert bearing design

 Bearing Technology

Proven, high performance bearing concepts for rotor shafts

In wind turbines, the rotor shaft arrange- Shaft bearing arrangement rolling bearing. The design as a double

ment is of central importance. This is The classical, repeatedly proven solution row tapered roller bearing is matched to where all the forces and moments act consists of a locating/floating bearing the operating conditions. This also applies directly that are induced by the wind. arrangement with spherical, cylindrical to the dimensions; large bearings can be The rolling bearings are subjected to or tapered roller bearings. over 400 mm wide and over 3 000 mm in highly dynamic loads and operating outside diameter. conditions. In partnership with customers, Hub bearing arrangement Rotor bearing housings the Schaeffler Group engineers develop The adjusted bearing arrangement the most efficient bearing arrangement contains two tapered roller bearings. Bearing housings calculated using state for each case. Low friction bearings from The alternative locating/floating arrange- of the art methods ensure the best INA and FAG are used in the power trains ment comprises a matched tapered roller possible support of forces and moments of modern turbines throughout the world, bearing and cylindrical roller bearing. with optimum dimensioning. In almost from 220 kW to the latest multi-megawatt all cases, development is undertaken class. Single bearing concepts for specific customer requirements and These designs combine the force and the housings are matched to the bearings moment support functions in a multi-row used.

 The ideal bearing arrangement for any gearbox

Increasing megawatt ratings require INA and FAG bearings used: tapered supplement existing models derived larger and higher capacity gearboxes. The roller bearings, cylindrical roller bearings from analogies and measurements. operating conditions for rolling bearings with cage, full complement cylindrical Higher operational safety and cost- in gearboxes cannot be roller bearings, deep groove ball bearings efficiency with tapered roller bearing units compared with those for static gearboxes. and four point contact bearings. Highly dynamic forces with extreme peak Ready-to-fit, optimum designs of tapered loads and minimal loads, sudden load New simulation calculations roller bearing units for high speed reversals and widely differing operating Deformation of the gearbox housing can gearbox shafts are be fitted quickly temperatures are some of the challenges place additional load on the bearings. without errors and reduce the logistics facing the bearing arrangements. Bearings Load peaks can also occur as a result of effort required. The internal clearance with high static load safety factor and braking and other influences in turbine is matched using adjusted intermediate secure dynamic design according to control. New simulation calculations rings. Load distribution and friction can international design guidelines such as of the dynamic behavior of the power be optimized by the effect of differing ISO 81 400 are the right solution here. train lead to precise load models and contact angles.

X-life. elements and mating track under identical With their optimized characteristics, X-life Higher cost-effectiveness. loads. This means: bearings open up completely new applica- Higher operational reliability. • reduced friction and tion prospects such as downsizing of the X-life represents premium products from the • lower bearing temperatures bearing support. Furthermore, the improved brands INA and FAG and gives completely new • less strain is placed on the lubricant price/performance ratio ultimately increases design opportunities for design engineers. • a higher basic dynamic load rating the overall cost-effectiveness of the bearing • a higher basic rating life. support. The use of state-of-the-art manufacturing technologies has resulted in a better, more Consequently, the operating life of X-life uniform surface over the whole contact face bearings is considerably longer under the between the rolling elements and raceway. same operating conditions. On the other As a result, there is a significant reduction hand, higher loads can be applied while in the stress conditions present on the rolling maintaining the same rating life values.

 Bearing Technology

Longer service life by current insulation

A generator operating in the of a wind turbine is subjected to significantly greater vibration loads than its counter­ part on the ground. This additional permanent load has a negative influence on the cages and places a strain on the lubricant. In the design of bearings for a generator, it is not only the speed, size and design that play an important role. Particular attention must be paid to the lubrication and protection against possible current passage. The bearing arrangement of a generator generally contains two deep groove ball bearings or one deep groove ball bearing and one cylindrical roller bearing.

Current insulation of generator bearings

The passage of current in a wind turbine generator can cause serious damage to the raceways of bearing rings in the form of melt craters and , lead- ing to enormous repair costs. It is there- up to 1 000 volts, even in a damp environ- fore appropriate to take precautions at ment. Hybrid bearings with ceramic rolling the planning stage to prevent such elements allow even higher values. In damage and failures, thereby helping to addition, hybrid bearings give longer save costs. In many cases, it is sufficient grease operating life. They are suitable to fit current-insulated bearings. Current- for high speeds and have good emergency insulated bearings are available with running characteristics. The use of coated rolling bearing rings and as hybrid these variants is based on the customer bearings with ceramic rolling elements. The requirements. Conventional bearings current-insulating, highly wear-resistant can be replaced by current-insulated layer consists of oxide ceramic and offers bearings at any time since the external protection against a puncture voltage of dimensions are identical.

 Wind tracking and blade adjustment Long-term mobility

Wind turbines must be aligned optimally mally dimensioning the blade bearings Azimuth drive/pitch drive to the wind in order to prevent extreme and by a maintenance concept specially Wind turbines adjust automatically due loads and to provide the highest possible designed to suit the turbine and the to active systems. Geared motors and energy output. operating conditions. actuators convert the signals from the

The blade bearing is also a significant controller. Schaeffler Group Industrial Blade bearing (pitch bearing) component of the safety concept of a offers bearing supports for slewing gears In order to control the power output of the turbine. The blade bearings must ensure for nacelle and blade angle adjustment wind turbine, the blade angle is always that the blades can be reliably and evenly from one source: optimally adjusted to the wind speed via adjusted under all operating conditions. • Input shaft – deep groove ball bearings the blade bearing. Very high loads occur • Planet gears – full complement in some instances from the dynamic load Tower bearing (azimuth bearing) cylindrical roller bearings of the rotor blades. These loads must A robust slewing ring is required in order • Output shaft – cylindrical roller be transferred securely via the raceways to adjust the position of the nacelle to bearings, spherical roller bearings, and the screw connections of the blade the wind direction. A particularly high tapered roller bearings bearings into the rotor hub. Single or level of reliability is achieved due to double row four point contact ball bearings the slewing ring’s generous design. The Blade adjustment with a cage are used here. The bearing wind load and the dynamic inertia forces In addition, the blade angle can be can be produced with internal or external are transferred securely and reliably via adjusted using electric or hydraulic gear teeth or without gear teeth depending the raceways and the screw connectors systems. These use sealed plain bearings on the blade adjustment concept of the into the tower head. Single or double with the maintenance-free Elgoglide® turbine. A long rating life and a higher row four point contact bearings with fabric, protected against corrosion by level of reliability are achieved by opti- external gear teeth are mostly used here. means of the Corrotect® plating.

 S e r v i c e

Remote monitoring and diagnosis

• prevents collateral and consequential damage, • protects individual turbines or complete wind farms.

The WiPro (Wind Turbine Protection System) is tailored to the requirements of the wind energy generation sector and primarily measures vibrations as well as, optionally, torque, temperature, oil quality and other

variables. The arrangement of the sensors at critical locations in the nacelle is based on the individual conditions of the turbine. When predetermined threshold values are reached, an alarm is triggered and data are transmitted automatically by landline, wireless or satellite modem to the F’IS Service Center. After intensive analysis and detailed in-depth diagnosis, the F’IS experts propose specific measures to the customer in order to avoid unplanned downtime and costly consequential damage. Security of planning is increased – replacement of components can be predictively scheduled. Only one system, in conjunc- Permanent monitoring of rolling bearings Online Condition Monitoring by the tion with competent and reliable support, operating under hard conditions in wind FAG WiPro system ensures reliable results. turbines is a fundamental precondition Online Condition Monitoring – the con- After in-depth checking, the WiPro for better profitability. For INA and FAG, tinuous monitoring of bearings in wind system has been recognized by Allianz this task is taken up by the experts of turbines Insurance. Other insurers also apply this the autonomous service company FAG • prevents unplanned downtime, benchmark and offer more favorable Industrial Services GmbH (F’IS). • detects emerging damage at an early conditions when the WiPro system is stage, used. The system and the monitoring • continuously monitors the condition facility at F’IS have been certified by of components, Germanischer Lloyd. Wind turbines of all • specifies emergency cut-off in response types can be easily retrofitted with this to preprogrammed conditions, system.

 Mounting and maintenance

Insurance provider rewards WiPro

Allianz Insurance confirms to F’IS that the online Condition Monitoring system WiPro fulfils the requirements of the Allianz Technology Centre (AZT) for Condition Monitoring systems for wind turbines. Allianz Insurance thus recognizes the WiPro system as suitable for condition-oriented maintenance. Alternative agreements may be reached with operators of wind turbines in the insurance variation clauses.

Offline individual measurements

As an alternative route to plant monitoring, F’IS offers individual measurement of With a wide range of mounting and If personal intervention is required, highly vibration and temperature data using alignment tools, measuring instruments qualified technicians and engineers are mobile diagnostic equipment. This and lubricants, more efficient work available on site, if necessary only a short method, for example in the form of processes can be designed. Thanks to while after the call for help. The recon- half-yearly measurement at the critical considerable FAG experience and its ditioning service for rolling bearings machine parts followed by analysis and qualified specialists, F’IS is the expert offered by F’IS with its short turnaround diagnosis, is a cost-effective alternative partner for customer-oriented solutions. times, makes a decisive contribution to despite its well-known limits and is cur- The preparation of individual service maintaining continuous availability. This rently still accepted by some insurers as strategies and practically-based training service is provided for rolling bearings a contractual precondition. improves reliability. from all manufacturers.

 Rolling Bearing Lubrication

Critical factors for service life

In addition to highly developed design Grease The advantages:

and precise manufacturing practice, the The main bearings and gearbox bearings • Fully automatic and almost reliability and operating life of a bearing in wind turbines are supplied with special maintenance-free is influenced to a large extent by lubri­ Arcanol rolling bearing greases. These • Precise grease quantities, cation. Selection of the correct grease, greases were developed in partnership no undersupply or oversupply the performance capacity of the oil, the with renowned lubricant manufacturers • Extended bearing life effect of additives, cleanliness in relation and subjected to comprehensive series • Higher cost-effectiveness due to to contaminants and adherence to the of tests before approval. They thus offer economical, environmentally-friendly specified lubrication intervals contribute consistently high quality and optimum metering to determining the quality of the system. lubrication characteristics. The F’IS range includes various lubricators of the Motion Oil Guard series that automatically feed the Recirculating oil lubrication with a filter correct quantity of fresh grease to the offers the optimum supply of lubricant to lubrication points. Depending on the the contact points. In condition monitor- lubrication system, dispensing times ing of important oil parameters such as between 1 day and 24 months can be set operating temperature, contamination, for up to six lubrication points. As a result, water content and viscosity, the filter less personnel work is required and should also be included. security in relation to lubrication of the rolling bearings used is significantly increased.

10 Calculation and Selection

Modern simulation and calculation programs

From the entire system right down to the rolling contacts

High costs are associated with the failure of a wind turbine. This means that all influencing factors must be considered in the best possible manner as early as the planning and design phase. We use the most up-to-date simulation and calculation programs in order to ensure optimum product selection.

Multi-body simulation

The dynamic behavior of the entire wind turbine is mapped with hybrid, multi-body simulation (MBS). Individual components of the drive train and the entire turbine design can be improved in the develop- ment phase using this model.

Bearinx®

® The software Bearinx can be used to With Bearinx®-online our customers can curves of the rolling elements and rings model and calculate all bearing types, calculate complex shaft systems with are determined, from which results complex shafts, shaft systems and even several bearing supports from the (e. g. for frictional energy) can be calcu- complete gearboxes. The support reactions, convenience of their office. lated for each time period. CABA3D can the internal loads in the rolling bearings, thus be used, for example, to calculate the comparative stresses of the shafts FEM the frictional energy transmitted and and the most important parameters are For even more detailed analysis, FEM the acceleration behavior of the rolling calculated and presented in tabular can be used to determine the influence of elements when they enter the load zone. and diagrammatic form. Obviously, the the adjacent construction on the rolling internal load distribution in the bearing bearings and vice versa. Telos is also calculated precisely – including Individual rolling contacts can be exam- contact pressure taking account of the CABA ined with the 3D simulation program Telos. rolling element profile. Based on the The MBS software CABA3D enables the Any rolling contacts under general lubri- individual rolling contact loads, Bearinx® dynamic analysis of rolling bearings. cation conditions can be considered and determines the calculated bearing life Taking account of all the degrees of it is possible to differentiate between more precisely than ever before. freedom, the force and movement plated and unplated bearing components.

11 Mandelkow

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