Blog: Copper v Silver: The Carbon Brush Debate

By BGB Innovation
schedule29th Aug 18

While not typically front of mind for the average person, carbon brushes play an integral role within modern day engineering, powering the motors and generators of thousands of essential innovations across the globe.

For the wind energy market in particular, the use and makeup of carbon brushes has shifted dramatically in recent years, and at BGB, we have witnessed the full impact of this changing marketplace – with copper alternatives playing an increasingly prominent role, compared to their silver counterparts, in many manufacturer’s designs. The reason for this? Simply a result of cost reduction across the sector. Copper carbon brushes are significantly cheaper to produce than the silver carbon alternative.

We have helped to power over 65,000 wind turbines worldwide with our range of silver carbon brushes and while these brushes may be small physically, they play a crucial role in the performance of these energy generators. Working in collaboration with slip rings and brush holders, they work to protect components from parasitic currents and ensure protection from lightning. Special brushes can even be optimised to work better in low- and high-humidity climates when needed.

Despite this reduced up-front cost for buyers choosing copper grade, it’s important that companies consider the long term implications when deciding between these and silver carbon brushes. In a wind energy sector estimated to be worth around $170B by 2024, those that can find the balance between minimal cost and maximum efficiency upon performance, will be those that lead the sector forward over the next decade and beyond. 

Still not sure which grade is right for you? Here we break down the key aspects of both of these types of carbon brush.

Copper carbon brushes

 

· Lower in initial cost.

· Life expectancy of 1-2 years.

· Wear down at a rate of approximately 29mm per year.

· Require higher levels of maintenance and repair compared to alternatives.

 

Silver carbon brushes

 

· Higher cost compared to copper carbon brushes.

· Life expectancy of 3-5 years.

· Outstanding current transfer.

· Wear down at a rate of approximately 16mm per year.

· Work more effectively in extreme environments.

· Reduced levels of oxidation when compared to copper carbon brushes.

· More efficient overall.

 

These points showcase the importance of communication between buying and technical teams to ensure wind energy firms are investing in solutions that are affordable, high performing and require minimal maintenance. While the low cost of copper carbon brushes might be a preferred option for those operating over a shorter term – the reduced maintenance and repair costs of silver carbon brushes may provide a more cost-effective option further down the line.

We have seen a major increase in demand for silver carbon brushes in recent months and it will be interesting to see if this shift continues.