If Designed Right, Carbon Brush is the Gold Standard for Shaft Grounding Devices

Shaft Grounding Systems, Inc. and DP&A Sales have been providing SGSTM shaft grounding systems for almost 30 years to just about every industry imaginable. Looking through our end user customer base, we tend to supply highly critical operations where reliability, performance and maintainability are required. This slant towards highly critical operations has organically occurred due to the established long-term performance of SGSTM products. Our customer base has often independently studied not only SGSTM performance, but other leading brands as well. These particular customers cannot afford to have a system failure down the road as the cost can be in the millions in terms of lost production time.

One of our core philosophies at Shaft Grounding Systems, Inc. and DP&A Sales is not to overstate what our products and services can provide and what claims we do make are based in fact. Our core claim that SGSTM non-drive end shaft grounding systems will perform continuously for 10 years at 1800rpm while eliminating electrically induced bearing damage is based on actual long-term field observational studies.

A literature review of competing shaft grounding systems would lead one to believe that carbon-based brush systems are a poor option for shaft grounding due to high brush wear rates. The following are excerpts taken from competing shaft grounding companies regarding carbon brush-based systems:

“High maintenance from wear, clogged spring and holder, brush dust and shaft glazing”

“Frequent periodic replacement needed because of wear” “High friction creates wear and requires replacement”

“Short life – often less than 6 months” “Carbon brush wears out must be replaced”

“Designed for DC current collector and commutator”

While the above critiques may apply to many carbon brush-based systems, they do not apply to SGSTM shaft grounding products. As a case example of brush wear rates, the following picture is of a brush that ran continuously for 10 years at 1800rpm at a high-tech manufacturing plant in Oregon, USA. Of note, this motor did not experience electrically induced motor bearing damage for the entire wear life of the brush. The beginning brush length was 0.88 inches long. The brush length after 10 years of continuous running was 0.68 inches.

Another brush wear rate example is of two combustion blowers at an Oregon papermill that ran for 9 years with max rpm of 1800. Brush wear after 9 years of bearing protected performance was 0.72 inches and 0.73 inches, respectively and with a beginning brush length of 0.88 inches.

These case examples are the norm for SGSTM non-drive end shaft grounding systems. SGSTM’s patented and proprietary designs and materials ensure that common problems such as too high friction and the environment are never an issue for long-term shaft grounding system performance. Where all other brush or microfiber grounding systems run radially on the shaft, SGSTM non-drive end systems run axially to the shaft which greatly decreases the degree of distance the conductive material travels. All non-drive end systems are sealed from the environment as standard.

When a brush eventually needs to be checked or changed, then maintenance can easily pull the brush from the shaft grounding system without shutting down the motor. This process is easily done in just a couple of minutes. A replacement brush is always available for same day nationwide shipment.

To further support our claims, Shaft Grounding Systems, Inc. and DP&A Sales have gone one step further. We asked a large university in the Southern United States to perform a 2-year brush wear rate study for SGSTM systems installed onto several clean room HVAC units. Their graduate students are taking interval brush measurements using a standard measuring procedure. We are looking forward to sharing their independent findings.

Pictured below an SGSTM CR Series shaft grounding system with the internally housed brush. The brush barrel cap is being removed to allow easy access to the brush for very infrequent maintenance. This simple process is done without needing to shut down the motor a unique feature to SGSTM non-drive end shaft grounding systems.