Shaft Grounding Devices

helwig BPK-4Shaft grounding devices minimize shaft voltage and prevent current damage. Shaft voltage can happen due to leakage, induction, or frictional buildup in other parts of an electrical system. Shaft groundings stop the energy from causing harm to vulnerable motor parts.


These devices redirect electrical current away from sensitive motor parts with weaker resistances—such as motor bearings—and provide a better route to the ground. Carbon brush technology from Emerson Bearing relies on a proprietary silver graphite material that provides superior protection against voltage and electrical currents. These solutions create the lowest possible resistance path to the ground, diverting the electrical force away from vulnerable electronics and hardware.

Emerson Bearing has four shaft grounding devices for optimal electrical protection:


  • BPK-IM2 devices with option dimensions for small motors
  • BPK-4 devices with standard option dimensions
  • BPK-5 devices with sealed option dimensions
  • BPK-AM devices with option dimensions for large motors

Benefits of Shaft Grounding Systems

Shaft grounding systems should protect vulnerable systems from bearing damage. This damage can occur when Variable Frequency Drives (VFD) used in AC or DC motors generate electrical currents on the motor shafts. This can also happen with PWM drives used in DC motors.

Electrical current always moves through the least resistant path until it is grounded. In most motors, bearings offer the lowest level of resistance and the current arcs across them, creating fluting, pitting, or other types of bearing damage.

Motor Diagram with a Shaft Grounding Device

Once motor bearings are damaged, they lose a significant portion of their functionality—bearings with rough surfaces can’t perform as well as bearings with smooth surfaces. The motors and connected equipment may suffer from excess vibrations and noise from the rough bearings. This may cause the equipment to eventually fail, which results in costly motor downtime, repairs, and delays

Adding a shaft grounding system gives the electrical current a more ideal path to reach the ground without damaging internal motor components. The shaft grounding device will lead current away from the motor bearings and allow the electricity to leave the motor in a controlled fashion. Shaft grounding systems keep equipment safe and save companies money in terms of parts replacements and lost time.

Using a shaft grounding device facilitates long-term equipment performance. These devices are simple to install in nearly all commercial and industrial equipment with motors. This includes wash down situations in food and packaging applications, where the system can be installed internally.

Click to Expand

Everything You Need to Know About Shaft Grounding Devices

Shaft Grounding Devices Applications

Motors in every industry need protection systems that divert harmful electrical currents away from vulnerable system areas. Common applications for shaft grounding devices include:

  • Air handling systems
  • Chillers
  • Compressors
  • Conveyors
  • Data centers
  • Elevators
  • Fans
  • HVAC units
  • Propulsion systems
  • Pump motors
  • Wind pitch motors

Emerson Bearing provides grounding devices with different options and in different sizes so every commercial or industrial motor system can be protected.

Shaft Grounding Devices from Emerson

Emerson Bearing has been providing ball and roller bearing solutions for more than 50 years. We produce high-quality bearings that are customized to meet the specifications of their intended application. We also specialize in equipment designed to keep bearings safe from damage that would inhibit full functionality.

Contact us today to find the right shaft grounding devices and ball bearing systems for your next project. Download our eBook, “Increase Bearing Service Life and Optimize Performance,” for an in-depth guide to extending the lifespan of your company’s bearing systems.


Browse our resource library!

Find custom product selectors, catalogs, CAD files,
eBooks, and more!


Ask us directly
Resource library