The requirements in the wind power industry have increased and today require versatile technologies and innovative monitoring solutions. On that too Mayr Antriebstechnik with its safety brakes set for pitch and yaw drives. The portfolio offers reliable, fail-safe and much more brake wind turbine from Mauerstetten.

Mayr clutch brake wind


High-performance pitch brakes for wind turbines

Mayr Wind Energy06.09.2023 | To ensure that wind turbines work as efficiently as possible, manufacturers and operators make many adjustments. In this regard, is currently characterized, inter alia, the trend that technologies from industry are now also migrating to wind turbines.

This is clearly visible in the Asian region. Here you bet Servo drives for pitch adjustment and largely replaces the regulated AC drives - in some cases even without adapting the components to the special requirements of wind turbines. This trend has now also arrived in Europe. When certifying systems, however, it must be assessed whether the pitch system, as the main braking system, meets the standards and guidelines - for example the Machinery Directive.

Permanent magnet brakes are reaching their limits

Common servo drives are often supplied with integrated permanent magnet brakes for protection. However, the industrial system quickly reaches its limits in the wind turbine because the permanent magnet brakes are not able to withstand the forces occurring there high friction work are designed.

Even if they are high holding torques offer, the brakes are quickly overwhelmed in an emergency stop or otherwise required friction work. The thermal overload that then occurs can quickly lead to failure of the pitch as the primary braking system of the system. It is therefore important that the friction work that actually occurs is always taken into account as a selection criterion for the brakes in the wind turbine.

Pitch brakes are becoming even more powerful

The trend is also in the Wind Turbine towards servomotors for pitch drives, where they largely replace regulated AC drives. This poses new challenges for the braking systems. Mayr Antriebstechnik provides its for the Wind power developed and optimized to the high demands of the wind turbines Roba stop M pitch brake .

Sensor technology protects WKA rotor blades from ice and damage

With a high performance density, the pitch brakes are suitable for applications with ambient temperatures up to +90 °C and temperatures on the mounting flange up to max. +120 °C. In the event of an emergency stop, these safety brakes perform high friction work. Classic servo brakes are integrated in the motor housing because of their open design.

This is preferably done on the A-bearing side of the engine. Roba-stop-M safety brakes can be placed inside and outside of the housing. With the closed design, the pitch brake already achieves protection class IP 54 as standard. If it is additionally sealed accordingly, it is even Degree of protection IP 66 possible, which enables the open mounting on the B bearing side.

Pitch and yaw brakes – also for use at low temperatures

Mayr top stop servo motorMayr offers a variety of pitches power brakes. The new Roba-stop-M pitch brake joins the Roba-servostop series, which can be installed in the motor on the A or B side, withstands temperatures of up to 120 °C and has a low mass inertia. The Roba alphastop brakes are available for A-side flanged designs. The motor must have an extended shaft or the braking system should be equipped with an integrated shaft.

The following must be observed: If the engine is e.g. B. dismantled for maintenance, the missing safety brake and safeguards are needed to avoid unwanted movement of the rotor blades or nacelle. Safety brakes like that Roba-topstop can remain on the system even when the engine is removed. They keep the drive train safe when there is no energy. These modular systems are available with precisely fitting mounting flanges and can thus be flexibly integrated into existing drives.

Incidentally, the problem of insufficient braking power in the event of an emergency stop is also present yaw drives even bigger. Significantly higher friction work is required there to bring the nacelle to a standstill. It is true that servo drives in this area are still much rarer than conventional AC motors. Nevertheless, they are already appearing in yaw drives. At this point at the latest, the common industrial solutions with permanent magnet brakes are overwhelmed. Users can therefore fall back on safety brakes from Mauerstetten that have been specially developed and tested for yaw drives.

 Devices for braking energy recuperation for electric drives

"All brake components are safely dimensioned and only made of high quality, tested and proven Materials made,” explains Andrew Merz, Product Manager at Mayr.

Condition monitoring for yaw and pitch brakes

Mayr Roba stop M newThe manufacturer is setting new standards with intelligent monitoring modules for its yaw and pitch brakes. Monitoring is also moving forward in wind power electromagnetic braken increasingly in focus. Especially in offshore applications, it is advantageous if maintenance work is bundled efficiently and carried out at exactly the right time. The drive specialist offers this with the Roba brake checker an optimal one Condition monitoring tool

“Our safety brakes are monitored sensorless with the retrofittable Roba-brake-checker module,” explains Andreas Merz. "The module is not only interesting for extended data exchange, but also as a classic monitoring solution". Through the extended analysis of current and voltage, it recognizes the movement of the armature disk and thus the status of the brake.

In addition to monitoring the switching status and critical coil temperature, the Roba-brake-checker also performs a preventive function monitoring for wear, functional reserve and errors. "When the tractive force reserve is reached, the Roba-brake-checker sends a warning signal at an early stage that the brake can still be operated for a certain amount of time," describes Andreas Merz of the advantages.

"During this time, the wind turbine operator or manufacturer can carry out the maintenance in a way that is tailored to his work process." Especially in offshore applications, this has decisive advantages if maintenance work can be efficiently bundled and carried out at exactly the right time, for example not too early and therefore too often .

With the new module, significantly more processes are mapped during monitoring than with microswitches and initiators. In a further expansion stage, the module also controls the brake and thus replaces one Rectifier. Switching state monitoring and brake control are thus combined in one device.

Condition monitoring without switch

Mayr Roba brake checker Wind"Due to the fact that the Roba-brake-checker works without sensors, i.e. no microswitch or proximity switch has to be attached to the outside of the brake to monitor the switching status Safety brakes can be used in the basic design,” explains Andreas Merz. “In addition, the additional cabling and the sealing of the switches and initiators that may be necessary depending on the degree of protection.”

Unlike the solution with switches and initiators, which are exposed to shocks and vibrations due to their installation situation on the brake, monitoring is carried out with the Roba-brake-checker from switch cabinet off, ie in a protected environment. Failures due to icing and false signals due to dirt such as friction dust are therefore excluded.

The electrical switching of the Roba-brake-checker in the DC version can also increase system availability. Because it arises no critical sparking more on the contactor, which can lead to wear on the contacts with normal wiring.

Tear-off protection for containers for oil changes on wind turbines

Mayr tear-off protection wind07.12.2018 | The change from Hydraulic System- and gear oil offshore Wind turbines is a challenge. Therefore, the company Speedwind Offshore has developed a container-based system for quick and clean oil changes at sea - currently the only one in the world with certification by DNV GL. The company relies on "EAS-axial" overload protection elements from Mayr Antriebstechnik for the tear-off protection.

Regular changing of the hydraulic and gear oils is an important prerequisite for a long service life of the wind turbines due to the heavy loads. In addition, fluctuating temperatures and weather influences affect the properties of the lubricants. With the Container SWOC 1.0 Speedwind Offshore from Wilhelmshaven has developed a system for quick, safe and clean oil changes on the open sea. The 20-foot container for sucking off and filling the systems is transported to the wind farms on ships.

"The container does not require any equipment from the ship, just space to park it," explains Uwe Thiele, Project Manager at Speedwind Offshore. “The container can be used on all ships that work in wind farms because it is certified by DNV GL (Det Norske Veritas and Germanischer Lloyd). This makes us the only company in the world that can offer an oil swap container with this certification.”

Safe and clean container filling

Mayr EAX axial newThe container has two separate hose systems for the sorted filling of Transmissionand hydraulic systems and is designed for both daily and continuous use. It meets the current international work and environmental safety standards according to Solas (Safety of life at sea) and Marpol (Convention for Prevention of Marine Pollution).

For example, a specially developed tear-off protection ensures that no oil can escape when filling or pumping out avoids thus reliably water pollution and environmental damage. The tried-and-tested EAS-axial overload protection elements from Mayr, the specialists for clutches and brakes from Mauerstetten in the Allgäu, are used in the tear-off protection.

These overload elements are installed in the safety arm of the oil change container and disengage when the tensile or compressive force becomes too great and exceeds the previously set value. The release force is set via the preload force of disc springs. In the event of an overload, the bolt inside the EAS-axial force limiter moves relative to the housing, thereby moving the switching segments radially outwards. The power transmission is thus immediately interrupted.

Reliable power limitation even in rough seas

"The breakaway protection is required when the ships - also with dynamic positioning systems (DPS) - can no longer maintain their position during the oil change process, for example in heavy seas, and drift away from the wind turbines," Uwe Thiele describes the device. “If the push (or pull) gets too strong, it locks overload element in our safety system and sends a signal to our PLC via the integrated limit switch. This triggers the so-called emergency and the oil pumps stop working. It all happens at lightning speed. An oil spill at sea is thus reliably prevented.”

Safety coupling protects non-destructive tunnel boring machines

The EAS axial are made of high-quality materials and have hardened functional parts. This gives you excellent repeatability. In trouble-free operation, they offer backlash-free power transmission with high axial rigidity.

"It is also important for us that the release force of these overload elements varies individually and adjust steplessly can,” adds Uwe Thiele. In addition, the free-running path of the elements when disengaging in the pull and push direction can be freely selected via the constructive length design. After the overload has been eliminated, the overload elements re-engage automatically when the central pin is returned to its original position.

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Simone Duration

Simone Dauer is a press officer at Chr. Mayr GmbH + Co. KG, Mauerstetten