Test stand for wind turbine yaw gearboxes

Wind turbines convert the kinetic energy of the wind into electrical energy. Their main components are the rotor, nacelle, gearbox, generator and tower. A key mechanism for efficiency is the yaw system, which turns the nacelle so the rotor blades always face the wind.

The yaw system consists of yaw motors that start the rotation, yaw gearboxes that reduce the motor speed and enable precise tracking, and yaw gears and bearings that let the heavy nacelle turn.

Gearboxes and gears in wind turbines face extreme loads: dynamic loads from changing wind speeds, torsional forces, axial and radial loads, and material fatigue from constant movement. Temperature changes also affect the material properties.

To make these critical components reliable and durable, thorough endurance testing under realistic conditions is essential. TMX gearbox test stands simulate these load scenarios and enable full tests in four-quadrant operation, where the drive and output sides can swap roles during the test.

The TMX gearbox test stand in detail

TMX offers complete solutions for testing wind turbine gearboxes. We design our test stands to test the complex requirements of these critical components under realistic operating conditions.

Test stand hardware

The TMX test stand is built to test two devices in parallel. On a massive base frame, the two gearboxes are coupled through a shared gear, which simulates the real operating conditions at the main gear ring of a wind turbine. Each gearbox is connected to its own load machine.

With this setup, one side runs a speed profile while the other applies load torque, closely reproducing the actual operating conditions in a wind turbine.

Automation and control

At the heart of the test stand automation is a powerful control CPU combined with a distributed measurement system for high-accuracy data acquisition, especially of the torque transducer signals. Two frequency inverters in the control cabinet drive the load machines.

Gearbox elasticity and the flank change in the gear mesh during direction changes are a particular challenge on gearbox test stands. TMX meets it with a dedicated approach: based on test measurements (frequency responses, stiffnesses), we first build a mathematical model of the controlled system that accounts for the inertia of the load machine rotors and the stiffness of the mechanical system. This model is the basis for the controller design and the configuration of the actuators. On all TMX gearbox test stands, an intelligent algorithm handles the passage through gear backlash.

Operating software

The TMX operating software guides the user step by step through test preparation and execution. The TMX test sequence editor makes tests quick and easy to configure.

During the test, the user sees the status of the whole test stand and of the current test step in real time. The user configures the load profiles in advance and defines for each test step which drive acts as load machine and which as speed drive.

A special feature is four-quadrant operation: in every test step, the roles and the direction of rotation can be freely defined. The load drive can apply torque in both directions. It can work against the speed drive (simulating tower inertia) or assist it (simulating strong wind). Extensive, configurable evaluation produces the result reports at the push of a button.

Summary

The TMX test stand for wind turbine yaw gearboxes is an efficient, flexible solution for demanding endurance tests under realistic operating conditions. Four-quadrant operation, a mathematical model of the controlled system and user-friendly software enable full tests with freely configurable speed and load profiles. Dedicated algorithms handle the passage through gear backlash, for reliable and meaningful test results.