Shaft Grounding Devices
Shaft 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.
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.
