Carbon brushes range

Mersen is one of the few manufacturers that develops and produces its own carbon brush grades in-house, drawing on over 130 years of tribology expertise.

This vertical integration - from raw carbon material to finished brush - means that every grade is engineered for specific current densities, peripheral speeds, slip ring materials, and operating environments, rather than adapted from a generic formulation. The result is measurably longer brush life, lower wear rates, and fewer unplanned interventions across all applications.

The range covers seven application families, from wind generator rotors to DC traction motors, grounding systems, and pitch control signal transmission. All grades are available in our five manufacturing plants across three continent, including in the US through Mersen PTT North America (Boonton, NJ), with major wind energy grades held in stock for same-week delivery.

Wind generator applications place specific demands on carbon brushes that standard industrial grades cannot meet reliably. 

A doubly-fed induction generator (DFIG) operates at variable peripheral speeds, is subject to continuous vibration, and must be maintained at nacelle height — making brush life the primary economic variable. Mersen's wind-specific grades are the result of direct field collaboration with O&M teams across the US onshore fleet.

• CG677: the most widely deployed wind grade in the US fleet. Compatible with both bronze and stainless steel slip rings. Close to 3,000 US turbines running CG677 as of 2017, with brush life exceeding four years on bronze ring platforms.
• CG626: recommended for wind power generators and wound-rotor slip ring machines. Field-proven for high current density applications at peripheral speeds up to 45 m/s.
• MC837: for applications requiring a higher copper content to handle elevated current densities under variable load conditions.
• HCH-30X / HCH-4X1: dedicated phase and ground grades recommended for the GE-Hitachi 1.X platform in combination with Mersen's SR 13-15 bronze slip rings.

For pitch motor control and hub signal transmission, Mersen's carbon brushes for signal and power transmission cover the specific low-current, high-reliability requirements of pitch drive systems.

Several structural advantages distinguish Mersen's carbon brush range from aftermarket alternatives:

• in-house grade development and production: Mersen controls the full carbon manufacturing process, from raw material selection to pressing, baking, and quality validation. Grades are not rebranded OEM products.
• tribology expertise: over 130 years of application science on brush-ring contact behaviour, allowing Mersen to optimise grade selection for specific commutator and slip ring material combinations.
• OEM approvals: grades including CG677 and CG626 carry major wind turbine OEM approvals and are referenced in GE-Hitachi platform maintenance documentation.
• application support: Mersen's technical teams provide grade selection guidance and on-site diagnostic support through the Windtracker programme for wind applications.
• system compatibility: Mersen carbon brushes are designed to work in conjunction with Mersen brush holders for generators, ensuring correct spring pressure, brush geometry, and contact stability across the full service interval.

In-stock availability and ordering

Key wind energy grades (CG626, CG677, MC837) and the HCH-30X/HCH-4X1 retrofit grades for GE-Hitachi platforms are stocked in the US. Lead times for standard grades are typically available within the week. For custom dimensions, special grades, or high-volume requirements, contact Mersen PTT North America directly at contact.ptt.na@mersen.com or through the Windtracker wind services team for field-paired supply.