Unique on the world market: The Bavarian specialist supplier Ematec AG, based in Memmingerberg near Memmingen has developed a new rotor blade traverse system that exceeds all previous features and standards on the market: As the world’s first rotor blade lifter, the new rotor blade traverse system Clamp RBC is able to grip all blade shapes available on the market – even future blade shapes. This is made possible by an automatically adaptive blade support which also ensures a variable compensation of the centre of gravity. In addition, what makes the RBC so special is its tilting angle of ± 60 degrees.
Thanks to this new technology, the RBC adapts itself exactly and individually to every rotor blade shape. The new traverse is thus able to safely grip and handle any blade shape available on the market with a weight up to 40 tonnes. Given the fact that the tilting angle has been enlarged and due to an adaptive blade support, the RBC can be used in a universal way in the wind power industry – both onshore and offshore. „This is a decisive advantage not only for wind turbine manufacturers, but above all for the service companies who are responsible for the maintenance of the wind turbines from different manufacturers,“ emphasizes Manfred Eberhard, CEO of Ematec AG. For a particularly environmentally-friendly installation, the RBC is also available in the ecological GreenLine version with a battery-powered electric motor.
„With the RBC we are responding to trends and to the current challenges our customers are facing as they have to install ever larger and, above all, gearless wind turbines. We are now offering the perfect solution, „says Eberhard. With its novelty, the Bavarian specialist supplier once again wants to set a benchmark on the world market for the efficient installation of rotor blades and strengthen its reputation as an innovative think tank for heavy-duty lifting devices. Some large wind turbine manufacturers already rely on the know-how of Ematec for single-blade installation.
Perfect fit thanks to adaptive blade support
The RBC is now the first traverse ever that adapts to all present and future blade shapes thanks to its hydraulically adaptive blade support. Individual, specially rubberized pads automatically nestle to the blade via a hydraulic system. It does not mean gripping in the classical sense, but rather holding the rotor blade. The forces acting on the blade are so low that nothing can happen to the blade as the adaptive blade support ensures a homogeneous load distribution with a contact surface of 2.5 m x 1.2 m per side.
Variable compensation of the centre of gravity
The RBC can be individually aligned to the different centres of gravity of all rotor blades. This variable compensation of the centre of gravity is achieved manually by the adjustment of weights at the traverse. This ensures that the centre of gravity of the rotor blade, the gripper and the gripper together with the rotor blade correspond with each other. „This prevents the gripper from an uncontrolled swaying when releasing itself from the blade after the installation to the hub and in the worst case causes damage to the blade. This is a huge issue in the industry, „explains the Ematec board member.
Tilting angle of ±60 degrees
The tilting angle of ± 60 degrees, was a requirement from the market, which was specifically implemented by Ematec in its innovation. The world’s leading wind turbine manufacturer Gold Wind from China explicitly demanded this large tilting angle. “ A one-sided tilting of +60 degrees is already standard, but also tilting to the other side is a bit trickier. Achieving the -60 degree was quite a challenge, but as a specialist supplier and special purpose machinery manufacturer, we wanted to face it,“ explains Eberhard. With the enlarged tilting angle, Gold Wind and Ematec are responding to the increased demands of single-blade assembly on gearless wind turbines. Great advantage in practice: Due to the great variability of the inclination of ± 60 degrees in both directions, the hub does not have to be rotated after each mounted blade. This makes the single-blade installation of rotor blades even easier, faster and more effective.
For blade weights up to 40 tonnes
In addition, the RBC has been designed for the next-generation of blade weights, as the rotor blades are getting longer and thus heavier. The new Ematec traverse reliably lifts and installs blades weighing up to 40 tonnes. „Only very few manufacturers on the market can do that. Considering that the maximum weight was only 15 tonnes a few years ago, this has been a huge development, „says Eberhard. Another advantage of the RBC: The distance from the crane hook to the centre of the rotor blade is just 3.7 meters. For the construction site, this means that possibly a smaller crane size needs to be rented than usual, which saves costs in the end.
Also available with battery drive
Appropriate for the renewable wind energy industry, the RBC is also available as a GreenLine version. Instead of a diesel engine, an electro-hydraulic unit with battery is used, which operates emission-free and almost noiseless. The battery is designed for a working temperature of -20 degrees Celsius and for a working time of 16 hours. Ematec therefore guarantees that even in cold temperatures it is possible to install three rotor blades in one day. With a charging time of 2.5 hours, even an empty battery is quickly ready to be used again. Another advantage: Thanks to the GreenLine version, wind turbine manufacturers may bypass the stricter emission regulations according to the Euro 5 standard and the US EPA Tier 4 final, which have been in effect since 1st January 2019. In addition, Ematec deliberately kept the electric motor below 24 volts, which makes it possible to be used in the US and meets the requirements of the UL (Underwriters Laboratories).
Like the former rotor blade lifter RBT and RBT Bunny from Ematec, the new RBC is also ready for use within just 15 minutes thus ensuring significant time and cost savings on the construction site. „By the time the traverses from other manufacturers are being assembled for operation, our rotor blade lifter has already mounted two rotor blades,“ explains Eberhard. The RBC is equipped with work lights for installation in the darkness. Via five cameras, the fitters are able to check every detail during the rotor blade installation – for precise work. Furthermore, the Ematec traverses are also equipped with GPRS, an integrated remote diagnostics system via Internet, that considerably speeds up and simplifies fault finding and troubleshooting. In addition, it has a logbook function similar to a black box of an airplane.
writer: Sabrina Deininger
The rotor blade lifters in use
A total of 15 Ematec traverses are used worldwide for the installation of wind turbines: 11 for Nordex and 5 for Siemens Gamesa. The traverses RBT and RBT Bunny (for bunny-ear installation) allow the gripping of the rotor blades in any turning position. The blades can either be picked up directly from the trailer or also from the ground. They are gripped by multi-joint gripping arms and rubber-coated gripper plates with a large surface. The form-fitting securing of the blade is ensured by a retaining claw.
Compared with similar systems, the Ematec traverses still come up with a decisive and unique selling point: In order to keep the windage area as low as possible, the rotor blades can be pitched in an angle range of -10 to +95 degrees. „This enables us to reduce the windage area by up to 50 % for certain rotor blade types. This provides the fitter with a high level of work safety as well as project safety, because with our traverse he is able to work safely even at wind speeds and gusts of wind whereas other systems are no longer able to cope”, explains Eberhard.
The design of the Bavarian engineers can be tilted by ± 8 degrees in the longitudinal axis. Even if the rotor blade lifter is not 100 % attached to the blade’s centre of gravity, it can easily be compensated without the blade having to be gripped again and without the operator having to balance the rotor blade.
The perfect combination of the pitching and tilting function also offers the operator great advantages when it comes to connect the blade to the hub, as the blade can be connected to the holes for the fastening screws with millimeter accuracy.
With the aid of suspended chains with a compensation rocker, the rotor blade lifters from Ematec can be hooked to a wide range of crane hooks in a comfortable, safe and time-saving way.
When working with Ematec traverses, the rotor blades are well protected against damage. The gripping plates are gimbal-mounted and automatically adapt to the shape of the blade. The rubber pressure plates always guarantee a secure grip, even in wet weather. They are resistant to light and aging and therefore leave no gripping marks. In addition, they can be replaced without tools.
Thanks to the redundant design of all technical resources, right through to the power supply, the highest level of working safety and functional reliability is offered by the rotor blade lifters. If necessary, the additional emergency engine can not only be started via the radio remote control, but in case of need also by hand. The work light at the traverse to illuminate the working area have also proven in practise. „For example, it was possible to complete some projects despite the onset of darkness. Otherwise the operation would have had to be stopped. Especially in Scandinavia, our illumination is very much appreciated because of the frequent night work there,“ explains Manfred Eberhard.
Individually adaptable to the shape of the blade
13.0 x 3.0 x 3.1 metres (L x W x H);
Economic road transport possible with only one semi-trailer.
Self-sufficient, redundant power supply via two diesel hydraulic power units with generator or alternatively electro-hydraulic power unit with battery (GreenLine)
Radio remote control with two radio transmitters including signover function for ground staff and for hub staff, including display of operating conditions
Two large work lights to illuminate the work area, can be switched off via radio.
Open design for easy accessibility of all components.
The rotor blade lifter has been type-tested by the Technical supervisory association TÜV Süd. Optionally available is the certification by DNVGL.
Am Ziegelstadel 3, D- 87766 Memmingerberg, Telefon +49 8331/9487-0, Telefax +49 8331/9487-740, firstname.lastname@example.org, www.ematec.de
The rotor blade Clamp RBC scores points with an automatically adaptive blade support and a variable center of gravity compensation. Graphic: Ematec