FAQs

What separates SGS^TM from our competitors? To our knowledge, SGS^TM shaft grounding systems were the first patented shaft grounding systems available on the market to address the issue of electrical bearing damage on VFD motors. Beginning out of the Pulp & Paper industry over 30 years ago, we have developed an extensive knowledge base that is field tested on shaft grounding system applications over many industries.

What is one significant difference between SGS^TM and other leading shaft grounding competitors? Our patented brush systems are designed to withstand severe industrial environments as well as environments sensitive to emissions. Our competitors use much of the same technology as office printers use for grounding static electricity from printer paper. Longitudinal trials of this “fiber-to-shaft” design is only marginally effective for vastly shorter times at decreasing shaft voltages than when compared to SGS^TM products.

How long can SGS^TM systems run prior to maintenance? Our CR, CM, CL and SR Series line of products have proven to run for over 10 years or 100,000 hours of continuous operation (1800rpm) prior to needing an inexpensive brush replacement. Maintenance can usually be done on the fly with our non-drive end shaft grounding systems.

Is there potential for shaft damage while running SGS^TM shaft grounding systems? Shaft wear is certainly a valid concern with most shaft grounding systems, however, SGS^TM patented brush designs do not cause shaft wear. This has been determined by 10+ year running trials. In addition, there is no need to coat the shaft with collaidal silver shaft coating material to promote conductivity. All SGS^TM products rely on very stable mechanical connections that will not require maintenance and are not negatively impacted by the environment over time.

Competitors state that spring loaded brush designs apply too much pressure and therefore wear out quickly. True? While this can be true for other brush based shaft grounding systems, our patented SGS^TM brush and rotor designs have proven to run as long as 100,000 hours at 1800 rpm prior to needing brush replacement. In addition, lab and field studies have shown the brush effectiveness lasts for the entire wear rate life of the brush. That is to say, voltages are maintained well below the threshold leading to capacitive discharge through the bearing for the entire life of the brush.

Do oils and other contaminants negatively affect how well SGS^TM shaft grounding systems perform? No. Our patented designs ensure a clean running surface at all times for the brush to run on. This is a critical differentiation as any grounding system needs to be the best competitor to the bearing for path of least resistance around the bearing and back to the motor frame. A system design that ensures a clean running surface must be achieved. To our knowledge, SGS^TM is the only shaft grounding system that achieves and maintains for the long-term a clean running surface ensuring a path of least resistance for current to flow around the bearing and back to the motor frame.

When using SGS^TM kits, do brush particulates affect the ability of the shaft grounding systems to properly ground? No. We have developed a line of products for use in the clean room industry (CR and CM Series). Extensive customer studies have proven that our patented sealed SGS^TM shaft grounding systems can operate in a clean room environment and continue to be effective at shaft grounding while not emitting significant contaminants into the environment at continuous operation at 1800 rpm.

Can our SGS^TM shaft grounding systems operate over a shaft keyway? Yes. If a non-drive end SGS^TM system will not serve your needs, then our SR Series split ring shaft grounding systems will operate over a shaft keyway without the time consuming process of filling the shaft keyway with epoxy, etc. If the key is part of the system, then SGS^TM will accommodate the key.

Are inductions absorbers effective at keeping shaft voltages below the threshold needed to prevent capacitive discharge through the bearing? In short, no. Our field experience and lab studies have shown that induction absorbers can decrease the peak voltages the motor experiences and can prevent first turn burnouts, however, they cannot decrease shaft voltages to the level that prevents capacitive discharge through the bearing. At best, these products only marginally slow down the effects of capacitive discharge through the bearing.

Is an internally mounted shaft grounding system superior to a shaft grounding system that is mounted externally? Internally mounted shaft grounding systems do benefit from being less prone to environmental contamination. However, a field analysis of this mounting arrangement has proven that keeping a path of least resistance is only marginally improved. In addition, internally mounted grounding systems are not at all maintainable. Once their grounding performance has waned (most likely due to poor wear tolerance), the motor is no longer protected and electrically induced bearing failure can occur. Replacing an internally mounted shaft grounding system is a very costly process.

How does our product support compare to other brands? DP&A Sales continues to support originally installed SGS^TM products from as long ago as 20 years. Nobody else provides that level of support. Our clients can call one phone number to get support and we can typically have parts shipped within 1 business day to anywhere in the United States.

What is the most important consideration when researching a motor shaft grounding product? Does the product provide and maintain a long-term path of least resistance for current to flow around the bearing and back to the motor frame? Electricity is simple in that it travels via the path of least resistance. Surface contamination and poor grounding system wear tolerance are the most common contributors to a failing shaft grounding system. As soon as the grounding system’s path of least resistance is compromised, current will find an alternative path of least resistance which we know will be from the shaft through the bearing and will lead to electrically induced bearing failure.

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