New rolling bearing solution minimises shaft
displacement and vibration in wind turbine rotor shafts 

A new bearing solution has been developed for supporting the main rotor shafts of wind turbines. The combination of tapered roller and cylindrical roller bearings with angular adjustment capability enable extremely narrow axial guidance of the wind turbine rotor shaft, which means that shaft displacement and the effects of vibration are significantly reduced.

Schaeffler's new bearing comprises a combination of tapered roller and cylindrical rolling bearings with angular adjustment facility. The solution combines the excellent characteristics of tapered roller bearings as locating bearings and cylindrical roller bearings as non-locating bearings. In addition, the design of the bearing housing enables the required angular adjustment to be made in order to compensate for any misalignment between the bearing positions.

Spherical roller bearings with high internal clearance
Up to now, the main shafts of wind turbines are normally supported by two spherical roller bearings used as a combination of locating and non-locating bearings, with separate bearing housings. Spherical roller bearings are able to compensate for any angular misalignment of the shaft and support the high radial and axial loads that occur in wind turbines.

However, the design of spherical roller bearings is such that relatively high radial internal clearance acts on the locating bearing side. This results in high axial internal clearance that is typically six to seven times higher than the radial internal clearance. If high axial loads occur at low speeds, during a sudden gust of wind for example, the spherical roller bearing moves in an axial direction. This leads to sliding movements between the rolling elements and raceway, which can damage the bearing over time. Axial displacement must occur via the bearing housing on the non-locating bearing side. This requires significant forces that increase the load on the bearing.
 
Ideal locating and non-locating bearing solution for the shaft
Schaeffler's new tapered roller and cylindrical bearing solution prevents high axial clearances that are found in spherical roller bearings.

Double row tapered roller bearings in 'X' or 'O' arrangements are ideal locating bearings. The bearings can be set with very little clearance or even with preload. The contact angles of the rows of rolling elements in the bearing are optimally adjusted to match the load conditions. The distribution of loads on both rows of rolling elements is therefore more uniform. The bearing supports the high axial forces acting on the shaft without any lateral sliding movement. Damage to the rolling bearings is therefore prevented and at the same time, tighter guidance of the shaft and rotor is possible.
 
In the second position, a double row cylindrical roller bearing is used as the optimum non-locating bearing of the main shaft. Here, the radial internal clearance is also reduced. The load distribution of the rows of cylindrical rollers is also more uniform. Axial length compensation no longer occurs via the bearing housing, but via the rolling elements within the bearing, which means the bearing is subject to significantly reduced loads.
 
Compensation of angular misalignment
An angular adjustment facility is also required for the bearing position of this bearing arrangement in order to compensate for shaft deflections. In a conventional solution, this is normally achieved by using a spherical roller bearing.

If tapered roller bearings and cylindrical roller bearings are used, static angular misalignments are compensated for by the spherical surfaces between the outer ring and housing. Both bearing outer rings have a spherical outside surface that is located in the concave locating bore in the housing. These spherical surfaces slide on one another similar to spherical plain bearings. Coating the surfaces improves the sliding characteristics and prevents fretting corrosion.

For further information, e-mail: info.uk@schaeffler .com or view website: www.schaeffler.co.uk   Refer to page 9

New UK systems integrator offers unique mix
of in-house design, engineering and software skills

A new systems integration company has been set up in the UK, which is offering customers a unique blend of in-house skills incorporating mechanical, electrical and software engineering.

The new company, Adansor Systems Integration - a division of leading pipe measurement products and services provider Optical Metrology Services (OMS) Ltd - will provide customers with a trio of core competences that incorporates all the key elements of systems integration projects: Mechanical (precision engineering, mechatronics and kinematics), Electrical (bespoke electronics and off-the-shelf product integration) and Software (PC-based, embedded and realtime systems).

On the design side, Adansor Systems Integration has in-house expertise in both mechanical and electrical engineering design, including certified SolidWorks Professionals. This enables the company to satisfy all clients' requirements on a systems integration project, including the creation of 3D CAD models, technical drawings, general assembly drawings, bills of materials and photorealistic renderings of integrated systems and components. These services also include custom PCB design using software applications such as 'DesignSpark' and 'MultiSim'.

In system build and manufacture, Adansor has unrivalled in-house prototyping, manufacturing and precision engineering capabilities at its facility in Bishop's Stortford. Here, bespoke components can be produced in a range of materials such as steel, aluminium, composites and plastics. Adansor also offers PCB assembly, including custom manufactured PCBs and duplicates, as well as electrical wiring carried out by fully trained and experienced technicians.

National Instruments LabVIEW Expertise
In most systems integration projects, National Instruments LabVIEW software* is now accepted as the simplest and most reliable means of interfacing and integrating different hardware platforms. The software offers industry standard platforms and programming for product testing, automated test sequencing, dynamic test scheduling, full reporting and statistical process control (SPC). Here, Adansor scores very high as the company's senior NI LabVIEW programmer, David Briscoe, is one of only 16 National Instruments Certified LabVIEW Architects in the UK. This means Adansor is able to offer customers unrivalled expertise in terms of software and hardware systems integration.

Richard Brown, Engineering Manager at Adansor Systems Integration comments: "Our mix of mechanical, electrical and software integration skills is unusual, particularly in the UK market, where most systems integrators are only able to offer one or two in-house core skills at best, with the rest of the work having to be outsourced to third parties. Because of its experience working on projects for OMS Ltd, Adansor is able to offer all the necessary design, manufacturing and software integration skills that are required on every systems integration or mechatronics project these days."

Alongside its expertise in NI LabVIEW, Adansor provides a range of custom PC and embedded control systems solutions, including microcontroller-based systems, industrial rack mount PC systems (Windows and Realtime-based), and distributed SCADA systems (including event logging and alarm monitoring).

On the data acquisition side, Adansor offers a wide range of custom engineered solutions, from low speed monitoring applications to high speed event capture. This includes synchronised acquisition using sensor data, video and audio, digital and RF communications. Data storage, data analysis, visualisation and reporting software are also important elements included here.

For further information, e-mail: richard.brown@adansor.com or view website: www.adansor.com

Corrosion resistant fork rod ends from Elesa

Fork rod ends from the Elesa FJT series are a proven method of transmitting linear control or actuation, such as pneumatic cylinders, and in the case of the FJT they are resistant to continuous washing cycles with solvents and detergents, so they are suited for example, to applications in food and pharmaceutical processing equipment.

The FJT fork rod ends are available in M6 to M14 sizes, manufactured from glass fibre reinforced polyamide based technopolymer. This ensures both very low weight and good stiffness, as well as low noise and excellent shock absorbing characteristics. In addition to food and pharmaceutical machinery, typical applications are expected to include pneumatic control systems, print machines, light mobile equipment, HVAC flap and valve controls and machine guarding actuation. In fact, all types of rod systems requiring component support/adjustment, actuation and manipulation - also in compensating for misadjustment or misalignment.

For further information regarding Elesa products, view website: www.elesa.co.uk   Refer to page 15

Global electronic access and environmental
monitoring for Colocation Data Centres

Our data focussed age has highlighted even quite recently the need for security on an ever broadening scale and colocation data centres are at the very heart of this need. Such centres handle information prioritised by its sensitivity or absolute value with highest security applied in a hierarchy from site access, per server room, per server section and per individual cabinet or cabinet compartment. They cover everything from aquisitions and mergers, corporate accounts, government records, financial services, potential manufacturing processes, policing, local government, global legal matters, online sales, personnel records, tax, media and telecoms. In fact every possible facet of our organised social economic lives.

The EMKA RMS 490 and Meta ELM Database are currently installed in one such Canary Wharf facility specified to pull together access and monitoring capability at numerous data centres in US, Canada, South America, Central and Eastern Europe, Africa, Asia and the Middle East from just two centres - one in London operating 12 hours a day and the other in India for the remaining 12 hours. This enables an access request to be actioned anywhere in the world within seconds, with high speed report-back of cabinet status and subsequent log.

The core of the database system is a Database Server (Microsoft SQL Server 2008 R2). Here, all components of connected ELM systems (all doors, sensors, relays, fan controllers, access cards etc) and their characteristics are provided in terms of data tables for evaluation or configuration. Writing into these tables yields corresponding changes in the ELM systems. That way you can configure ELM systems or - for example - open doors by writing into a data table or by executing SQL commands or scripts.

Basically the database is an open platform for different GUI applications. Customers may use database client tools of their choice. The database allows for operations (configuration, searching, monitoring …) across the boundaries of a single ELM system.

Within the RMS 490 19" package 8 inputs are available for electromechanical locking systems and door contacts. Opening a lock is via keypad and pin code, transponder cards, mobile phones and of course via network and SNMP commands.

Up to 4 sensors can be connected to monitor ambient conditions like temperature, humidity, acceleration (vandalism) and issue alarms via 4 relay contacts which can all be managed under one IP address.

Needless to say in data centres containing some hundreds of racks it may be that only a proportion of the cabinets are required to have such a high level of security - the ELM system incorporates expandability and versatility using daisy chained modules on CAT 6 cables so that more cabinets or more sensors may be readily added e.g. for tilt and humidity.

Individual cabinets may be operated locally by HID card based personnel proximity reader or even by manual key override should the need arise. Further information on EMKA products and services may be found at: www.emka.co.uk where it is also possible to download their 3D CAD files and any part or the entire EMKA product catalogue.

Find the latest information and news on the EMKA blog - www.emkablog.co.uk  Refer to page 15