Rotary Limit Switches for Precise Position Signals in Wind Turbines

Wind energy

As wind energy becomes more prevalent across the world, wind turbines are becoming increasingly powerful. At B-COMMAND, we have built strong relationships with some of the biggest companies within the wind energy sector. Based on this long-standing tradition, we have been able to specialize our products based on the needs of our customers. In this article, we will explore how energy output can be maximized with rotary limit switches from B-COMMAND.

What products are typically found in wind turbines?

While there are a variety of components to the wind turbines, B-COMMAND offers a few highly specialized products, including rotary limit switches for yaw drives, rotary limit switches for pitch drives and pinion gears specifically designed for use with encoders and rotary limit switches.

For many years, rotary limit switches have been used in wind power applications. Here, two main applications can be covered:


Pitch Control System:

Rotary limit switches

As part of the pitch control system, the rotary limit switches measure the position of the blades very precisely. By changing the blade pitch, the rotation speed and generated power can be adjusted, which has a major effect on the efficiency of the blade. Usually, the limit switch is connected either directly to the gear rim (each blade with one separate rotary limit switch), or to the drive pinion of a pitch motor via a measuring pinion.

Yaw Control System:

As part of the yaw control system, rotary limit switches measure the movement of the nacelle and forward the position signal to the plc. This information combined with the wind direction sensor of the wind turbine is used to keep the turbine perfect into wind direction and detect changes in wind direction in order to adjust nacelle position.


Additionally, the limit switch is used for cable twist protection. The movement of the nacelle is limited to 2.5 to 3 revolutions to protect the cables hanging in the tower from twisting and thus from being torn or damaged. The mechanical contacts inside the geared limit switch are adjusted to the maximum position left and right and are activated when reference positions are reached.

Resistant to cold, wind, and rain

Pitched limit switchWind turbines need to withstand harsh environmental conditions, including wind and weather, 365 days a year. Since many wind turbines are located in remote and difficult to access locations, wind turbine manufacturers and their suppliers rely on the unconditional reliability and quality of all components. Although the limit switches are arranged in a relatively protected manner inside the wind turbine nacelle, temperature fluctuations, air humidity, and in some cases, mechanical requirements from the wind load act on the components. B-COMMAND has therefore carefully selected all materials that are in direct contact with the environment, to ensure resistance to gases, oils, and extreme temperature changes. A circumferential rubber seal enables good protection against dust and water so that protection class IP 66 can be achieved without any problems. By switching to polyurethane insulation, instead of PVC, our products can withstand temperatures down to -40 ° C. This is to further ensure the safety and reliability of these products to ensure that minimal maintenance is required.

Maximum efficiency with yaw control

Pinion Gear

In order to gain the maximum efficiency of the wind turbine generators, it is necessary to keep the rotor perpendicular to the wind. Yawing the turbine against the wind reduces fatigue loads and ensures increased durability of all components as the switch monitors the rotations and limits the end positions for each direction. In addition, B-COMMAND is able to mount different types of encoders within the switch to monitor the exact yaw position. Depending on the type of encoder, we are able to reach an accuracy of 0.001 °.

The switches from B-COMMAND can be connected by a pinion gear either with the yaw bearing around the outer edge or with the gear wheel of one of the yaw control engines. We also offer a number of standardized or custom solutions depending on what you need, all of which can be found in our wind energy catalog . If you are unsure which solution is the best fit for your product, we encourage you to reach out to our customer service representatives who will be happy to help you.