Compact power pack reliably slows down rotor blades

The rotor blades, gearboxes, tower and foundations are the most cost-intensive components of a wind turbine. Their life cycle can be increased by the way of the hydraulic actuation of the wind turbine's azimuth and rotor brakes. The compact KA type pump power pack from the Munich-based HAWE Hydraulik SE is ideally suited for the brake function of the rotor blades. In addition, when combined with the manufacturer's directional seated valves its function is extremely secure.

The KA type was developed for accumulator charging and intermittent operations. It consists of a tank with integrated immerged oil motor, a radial piston pump that is directly mounted to the motor shaft - without a clutch - and a connection block. The function modules are mounted directly on to the connection block. The modules are separated for each function, as for example the brake function. This modular design offers the advantage that any potentially faulty module can be easily identified and swiftly exchanged by merely releasing four screws. There is no need to remove any hoses connected to the consumers.

The radial piston pump supplies pressurized oil for operating pressures of up to 700 bar. Three tank extensions are available to meet different requirements in oil volume. Depending on the tank extension the deployable volume can be increased from two to ten liters. The KA2 and/or KA4 types can even be upgraded to a maximum of 20 liters. The power pack can be operated with all voltages, including 690V. In case of grid loss the hand pump is used for emergency operation of the brakes.

The KA type can be installed either vertical or horizontal and is also available as "Cold Climate Version". This version has the heater activated by means of the motor winding and does not require any additional elements. On the other side experience shows that with the appropriate selection of the pressure fluid there is no need for a heater.

For safety reasons the brakes of a wind turbine must work reliable at any time. HAWE Hydraulik's zero-leakage directional seated valves offer considerably higher switching reliability than the directional spool valves as dirt particles are flushed out again when the valve is opened. By this way the clearance of the valve piston in its guide bushing cannot clog and thus choking of the valve is prevented. As the valves are designed for pressures above 400 bar, while the pressure level of wind turbines is normally below 250 bar, the valves used in these facilities are extremely long-living.

At HAWE Hydraulik all pressurized components are made from steel. This way the components' design can be compact, their installation space and inherent weight are comparatively low. Transporting the KA compact power pack therefore does not require a crane.

For wind power plants HAWE Hydraulik offers active and passive brake control, with or without a flushing function for the brake lines and brakes. Additional function modules are available for adjusting the pitch, roof openers for the turbine nacelle, rotor locking, and the control of on-board handling cranes.