Carbex has for many years developed and tested wind power carbon brushes in Inner Mongolia, noted for its extreme weather conditions both in terms of temperature and humidity variations.

Carbex manufactures carbon brushes for all types of wind power turbines and generators on the market including, among others, to Vestas, Gamesa, GE, VEM, Winergy, Siemens, Nordex, Suzlon and Loher.

Advantages:

• Exceptionally long service life
• Minimal ring wear
• Superior film formation for low friction
• Outstanding performance from no load to high load
• Outstanding performance maintained in varying atmospheric conditions and low humidity
• Contamination tolerant

A large market area for Carbex is the grounding of motor shafts.
Carbex also supplies brush holders for grounding.

In those cases where galvanic currents pass through motor’s bearings they can damage them. The grounding brushes’ most important function is to prevent the current from passing through the bearings and thereby prevent damage. Galvanic currents cause small pits and grooves which result in higher friction in the bearing. Metal graphite brushes with high metal content are usually used for grounding brushes. Silver graphite is the best choice because silver materials are less affected by oxidation, but copper graphite can also be used. Pure metal graphite brushes cannot cope with such high peripheral speeds.

At higher peripheral speeds additional lubrication may be required. We recommend sandwich-type brushes which consist of graphite that lubricates and silver graphite that gives low resistance.

Thunderstorms and lighting strikes are the worst enemies of wind turbine stations. It doesn’t matter which type of generator is installed – asynchronous or synchronous – it needs an effective lightning protection system. The components that are most vulnerable to direct lightning strikes are the blades, the tower itself, the nacelle and the lightning receptors on the nacelle.

Three main areas need to be protected:

• The connection between the blade and hub
• Main shaft
• Yaw ring

We offer carbon brushes with:

• Low voltage drop
• No thermal expansion in the event of extremely high current spikes
• Low wear and tear

WIND POWER CARBON BRUSHES

Carbex supplies carbon brush grades for pitch systems. Pitch systems should only be equipped with one quality that can handle both power and signal transmission. It is therefore of the utmost importance that the selected brush quality is capable of operation with and without power, as well as attenuating the noise level, as the carbon brush is for signal transmission. Carbex selected grades are based on a fine film formation even when the currents are low warranting minimal brush wear. Carbex can also offer complete systems, i.e. slip rings, brush holders and carbon brushes which are adapted for maximum performance and hassle-free operation.

Our development department has, among others, developed an innovative brush holder that generates a longer service life for pitching. The carbon brushes mounted on the brush holder have a wear length of no less than 22mm!

The system uses constant force springs to give the same brush pressure throughout the service life of the carbon brush. This solution can be used for both power and signal transmission. Silver grade carbon brushes should be used for signal transmission which generate low noise levels and a transmission speed up to 100 base-T.

The system can easily be modified for the desired number of channels and the power and signal transmission tracks can also be freely chosen.