Rotary Limit Switches

Wind turbines use rotary limit switches to monitor the jaw position and as a safety device on the jaw. Some have also seen benefits of using the small compact rotary limit switches in pitch systems.

Motors controlling the rotation of a wind turbine on the yaw axis (or rotation of the blade around its longitudinal axis) transfer the movement to the rotary limit switch. A rotary encoder reads the rotation of the shaft, and its pulses are sent to a PLC which controls the position of the nacelle or of the blade. The movement of the shaft is also transferred through a gearmotor to a series of cam switches. The optimum setting of the actuating point of the cams can signal up to four critical positions of the movement of the nacelle or of the blade.

World leading Italian manufacturer Tecno Elettrica Ravasi srl (TER) has manufactured tens of thousands of rotary limits switches for wind turbines globally. Due to quality and continuous development TER is the number one on the global market in this field.

Typically a pinion gear is mounted on the shaft of the rotary limit switch. After a set number of revolutions, the cams operate the switches of the rotary limit switch.

Rotary limit switches are available in a wide range of versions for any wind turbine application with a large portfolio of standard pinion gears, integrated cams, potentiometers, encoders or as may be requested by global clients.


Small overall dimensions, IP42, IP65 or IP66/IP67/IP69K, revolution ratios ranging from 1:15 to 1:1500, 2, 3 or 4 switches.


Small, IP66/IP67/IP69K, revolution ratios from 1:3 to 1:2800, 2-3-4 switches, potentiometers, encoders, electroninc cards.


IP65, different revolution ratios on the two outputs (from 1:1 to 1:969), max. 8 switches or switches and potentiometer.


IP66/IP67/IP69K, different revolution ratios on the two outputs (from 1:1 to 1:1550), max. 8 switches, potentiometers, encoders.


Small overall dimensions, IP42, IP65 or IP66/IP67/IP69K, revolution ratios ranging from 1:15 to 1:1500, 2, 3 or 4 switches.


IP66/IP67/IP69K, saline fog resistant, revolution ratios ranging from 1:1 to 1:9400, 3 outputs, max.12 switches, potentiometers, encoders.

Pinion gears

In addition to the Rotary limit switches of TER we offer a large range of pinion gears.

Pinion Gears in materials, with special module sizes and numbers of teeth designed for wind power usage.

The pinion gears may be supplied already assembled on our rotary limit switches or on encoders.

All pinion gears are designed and tested for heavy duty applications where choice of the right materials plays an important role. Our full range is produced of special thermoplastic materials certified for operational temperature of -40°C, which is unique on the market.

In our data sheets you can see some of our standard pinion gears which are constantly available for urgent delivery.

Beside the standard solutions we have access to the basic necessity of a flexible tooling process and production. Through our network of partners we are able to manufacture prototypes of new types of pinion gears within few weeks and arrange series production after five to six weeks.

Based on this special process the production of new tools is profitable also for smaller series.

We would be pleased to execute a calculation of profitability also for your demands of pinion gears not listed in our standard range

Crane Accessories

With increasong sizes of wind turbines cranes build into the nacell is also becomming standard.

For operation of cranes TER offer a wide rage of portefolio of joysticks, remote operation panels etc.

Please contact sales departments of Wind Cluster for further information.

​For more information on rotary limit switches please read hereafter or contact our sales department.

​For more information on the large range of pinion gears please read the selection guide hereafter.

Wind Cluster ApS

Haarup Bygade 28
​DK-8600 Silkeborg

Contact us

​Phone: +45 70202256


Wind Cluster®

CVR: 32938973