Depending on the type of application, some maintenance may be needed on slip rings. It all depends on the number of rotations and/or the environment the slip ring is in.
A large portion of the applications do not require regular maintenance. For example, a slip ring in a crane will never see one million revolutions as where a slip ring in a wind turbine will see ten million per year. Generally in cranes no maintenance is performed unless a failure has occurred. The majority of these can be fixed with electrical cleaner and by simply rotating the ring. Normally the failure is due to a lengthy period of downtime where the slip ring is not rotating. When it's not rotating, it allows the brass rings to corrode. Since UEA brushes run a very high contact pressure compared to most, they will clean the rings as it starts to rotate.
The continuous rotation applications, like wind turbines, do require some basic maintenance to prevent any malfunctions or damage. This type of preventative maintenance needs to occur at most once a year. The cleaning of an assembly is as easy as removing the brush dust from the internal components. This can be done with compressed air, a vacuum and brush, or a combination of both. Lubrication is never required in UEA slip rings, as the brushes themselves contain graphite. Generally it takes 5 minutes or less to remove the dust and this will help to prevent any issues, especially with communication circuits.
In continuous rotating applications, UEA now installs a separator plate between the power and communication/data rings to keep the majority of the dust off the data side. This removes the chances of dust causing problems with the data circuits and can greatly lengthen the cleaning intervals.
In conclusion, maintenance on UEA slip rings is sometimes needed. However, performing this very minimal procedure will save a lot in downtime and repair costs in the long run. More specific maintenance information can be found on your application by contacting UEA engineering.