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How you as a plant operator can reduce storage costs and remain flexible
Shaft grounding systems for industrial plants
Reading time: 4 Minute(s)
Date: September 8, 2022
Machine Design

One grounding system for a wide variety of waves

If one of your production plants breaks down, this is associated with high costs. Damaged bearings are often the reason for expensive downtimes. The cause: parasitic currents that find their way through the rolling bearings of the plant. Shaft grounding systems can reliably remedy this situation and discharge voltages to the plant ground.

But we know that many of our industrial customers still face a dilemma: This is because shafts with a wide variety of diameters are installed in the gear units of their production plants. This means high storage costs, as they have to keep various sizes of shaft grounding systems in stock for emergencies.

We will show you how you can now ground a wide variety of shafts with just one system and reduce your storage costs:

One grounding system for a wide variety of waves

How vagrant shaft currents are created

There are several aspects that can lead to wave currents.

The top 3 reasons for vagrant shaft currents are:

  • Asymmetry in the magnetic field of a motor
  • Electrostatic charges
  • High switching frequencies of modern frequency converters

Vagrant shaft currents can lead to production downtime

Problems with electrostatic charges and high switching frequencies in electric motor systems can be found in every industry. They cause vagrant shaft currents that like to find their way across the machine's rolling bearings.

The high current densities cause local melting of the metal surface there. The surface is damaged and the premature failure of the bearing inevitably leads to expensive production downtime. But that's not all: the motors themselves, as well as gear components, can also be quickly damaged by these high-frequency currents and require unplanned repairs.

CFG system for railroad applications during installation from Schunk
Bearing failure due to microwelding from built up high frequencies are the most common issue with ungrounded currents.


In order to avoid expensive plant downtimes, shaft grounding systems that reliably dissipate vagrant shaft currents are already in use in many industrial sectors. What has been missing, however, is a standard solution that meets all the requirements of the various industrial applications.

Grounding carbon brushes reliably dissipate vagabond currents

Grounding carbon brushes have become the most popular choice for shaft grounding. These electrical contacts are designed to transfer electrical charge across the sliding interface between contact surfaces. Grounding carbon brushes have been used successfully in industrial and wind power applications for decades.

Advantages of grounding carbon brushes

A grounding carbon brush conducts extremely low amperage. The electrical wear factor is therefore negligible. With Schunk's extremely low-friction graphite-based contact materials, mechanical wear is further significantly reduced. The result: You benefit from a very long service life of the modern shaft grounding brush.

 Grounding brushes for shaft grounding of wind power generators from Schunk Carbon Technology
Grounding brushes for windpower applications are characterized by a long service life.

Flexible protection of roller bearings

In addition to the proven technology of carbon grounding brushes, we have developed a standard solution based on carbon fibers. The Schunk Industrial Protecting System, or IPS for short. The system is our first choice for carbon fiber grounding and can be used for a wide range of industrial applications.

Manufacturing process makes Industrial Protecting System particularly durable and conductive

For the Industrial Protecting System, we rely on a special manufacturing process: We use a strand of thousands of carbon fibers that have previously been treated in a chemical steam infiltration process. In addition, the fibers are processed in a vacuum reactor normally used for high-purity carbon products for crystal growing and microelectronics. The result is a fiber stabilized by pyrocarbon infiltration and coating with excellent conductivity.

Flexible design for universal use

The design of the Industrial Protecting System allows us to cover a wide range of different shaft diameters with one standard size. This means you only need one product to ground shafts from 29 to 450 mm in diameter. This is a major advantage over all other existing products.

By comparison, you often need more than 100 different sizes of conventional grounding systems in stock to cover the same range. Other advantages: The structure of interwoven carbon fibers ensures optimal contact and high abrasion resistance. The system can be adapted to your industrial equipment according to your needs. It is suitable for a rated current of up to 10 amps.

The Industrial Protecting System has a compact design and is universally compatible.

The advantages of the Industrial Protecting System at a glance

  1. universal bearing protection system for DC and AC applications.
  2. one system for different shaft diameters, instead of expensive single solution
  3. slim design allows mounting even in compact installation conditions.
  4. easy to retrofit due to compact dimensions.
  5. expensive coatings of the bearing surfaces are no longer necessary.
  6. high wear and abrasion resistance of the fibers coated with Pyro-Carbon.

Would you like to know more about our grounding solutions? Just get in touch with our experts!