This week: TWK-ELEKTRONIK: New products for the wind power industry

TWK has already been supplying the components – particularly rotary encoders – for wind power plants for 20 years, since the wind power industry was in its infancy. However, the product range has been continually extended since then with the result that rotary encoders are now by no means all that is on offer; instead, new sensor system devices and appropriate accessories have been included in the portfolio and are also available.

These devices include the new vibration sensors and also inclinometers as well as the tried-and-tested electronic switching cam encoders, vast quantities of which are used by a number of wind turbine manufacturers for pitch and yaw regulation. The NVA vibration sensors and NOC switching cam encoders, in particular, have been developed in close co-operation with wind power customers to meet the specific requirements important to the wind power industry. Long-term contact with customers constantly leads to progressive and tailored products which are also very interesting in price terms.

TWK: "Today, our wind power industry customers have to negotiate for every euro on the highly-competitive wind turbine market. This compels component manufacturers to implement specifically developed devices without any unnecessary and thus expensive features. Thanks to our good relations with our customers, we discuss the form the products are to have. This interaction between the customers' wishes and our long-term experience in the diverse field of sensor systems leads to a result which satisfies both parties: a good and inexpensive product."

The two above mentioned products, in particular, are not limited to purely registering the measured variable (vibration acceleration or shaft positions) but also offer a range of relay switching outputs which are activated on exceeding specified values and thus notify the control system and the connected peripheral devices that a reaction is required. During yaw regulation, for example, the system may have to be reversed by several revolutions to prevent the internal wiring harness from tearing. This is where the NOC comes into play.

Or in the case of excessive transmission or rotor vibrations, the system is shut down; this is initialised by the NVA. The corresponding values can be parameterised by the customer in a number of models. Or TWK sets all parameters as required in the factory. This is particularly interesting for series production. The customer can choose from a wide range of interfaces and designs.

Of course, development has not come to an end by any means. The concept of safety, in particular, is playing an ever increasing role. Due to Germanischer Lloyd guidelines, wind power plants have to meet higher standards of safety. Naturally, this development also encompasses the components which are installed. TWK-Elektronik has now had a range of sensors certified to SIL2. Rotary encoders, with their diverse interfaces and safety profiles, are already virtually commonplace – PROFINET, Ethernet IP, EtherCAT, to name just a few. The electronic switching cam encoder and the vibration sensor will follow shortly to meet market requirements and make these components fit for use in the safety chain.

As an accessory, the play-compensating toothed gear ZRS developed by TWK plays a crucial role. It enables rotary movements to be transferred precisely without mechanical measuring errors due to tooth flank gaps – and therefore also without any reversal play – to the rotary encoder from a crown gear. This toothed gear is frequently used to increase the measurement accuracy and thus the efficiency of a wind power plant.

The experience of TWK's employees and the know-how which they have acquired over a number of years have led to this positive development, which will also benefit the company and its customers in the future.