Carbon brush holder promises reduced wind-turbine maintenance

Carbex V-type carbon brush holder reduces maintenance costs by ensuring all carbon brushes are subject to the same wear

An innovative carbon brush holder, set to reduce maintenance costs for doubly fed generators in wind turbines, will be introduced by Carbex at the AWEA WINDPOWER 2013 exhibition in Chicago, May 5 to 8 in booth 1011.

Slip rings with carbon brushes are used for transferring power between the rotating and the stationary parts of the structure on all doubly fed generators, the most common type of wind power generator. The Carbex V-type brush holder ensures that all the carbon brushes push against the slip ring with equal force, preventing uneven wear and premature brush replacement. This also reduces electrical and mechanical losses, lowering the temperature of the carbon brushes and improving their lubricating properties. In addition, remote monitoring is simplified because it requires only one switch per phase

A traditional brush holder set-up includes a number of brushes fitted around the slip ring and individually adjusted. Brushes typically wear unevenly because each has different pressure against the slip ring.

The V-type holder eliminates these variations. The brushes are fitted and locked into position in single brush pockets. Through equal load on all carbon brushes, and lower temperature, the V-type holder gives longer life to the brushes, resulting in longer service intervals. This can mean substantial savings on maintenance because visits to remote locations are costly, particularly in offshore applications.

The V-type holder design simplifies fitting and facilitates service, saving time while on site. The compact holder is located just inside the inspection hatch of the slip ring compartment for easy access. Only one adjustment is required for the holder. There is no need to adjust the angle and contact surface of the individual brushes.

The Carbex V-type holder is patent-pending in the U.S., EU, and China. It is available for all common designs of doubly fed generators in the market. The design is modified for the requirements of each OEM to fit the existing bolt holes in the shield. The metal parts are machined, unlike traditional brush holders which normally have cast metal parts. This means tooling costs are eliminated for the OEM. The V-type holder is intended to offer the lowest life cycle cost possible, from the factory to service on site.

Carbex,  joakim.hedlund@carbex.se

www.carbex.se