A single VFD-driven motor can take a paper machine down. Protect your mill's motors from the electrical bearing damage that variable frequency drives cause.
In a paper mill, motor reliability is production reliability. Nearly every motor runs on a variable frequency drive (VFD), and the shaft voltage those drives create is a leading, preventable cause of bearing failure.
SGS shaft grounding removes that threat, keeping your machine and your mill running.
Trusted by Leading Pulp & Paper Companies
Just a few pulp & paper companies that have SGS installed are Georgia Pacific, Domtar, NORPAC, International Paper, Clearwater Paper, Chesapeake Paper Products, and Appleton Paper (Appvion), helping protect critical motors from bearing damage and premature failure.
A paper machine is a chain of VFD-driven sections that all run together. When shaft voltage takes out a single drive bearing, the cost isn’t one motor, it’s a stopped machine and the product ruined inside it.
The exposure is often widespread and unseen. Many mills have added variable frequency drives to motors that were never built for them, leaving bearings at risk across the line, from the wet end to the dryers, long before anyone links the failures to shaft voltage.
Shaft Grounding Has Roots in the Paper Industry
SGS’s work on electrical bearing damage began in a mill. The first research identifying VFDs as the cause of electrical bearing damage was carried out at a paper mill in Albany, Oregon, solving the same failures mills still face today.
Decades later, that experience is built into every SGS system. You can read the full background in our overview of bearing damage due to electrical discharge.
Where Shaft Voltage Threatens Your Mill Motors
Any VFD-driven motor can develop shaft voltage. In a pulp and paper mill, that reaches from the machine itself out to the supporting systems.
On the paper machine:
- Sectional drive motors along the machine
- Dryer section and calender drives
- Winders and reels
Throughout the mill:
- ID, FD, and hood exhaust fans
- Stock, process, and vacuum pumps
- Refiners, pulpers, and agitators
- Conveyors and other VFD-driven equipment
SGS Shaft Grounding for Every Mill Motor
SGS Shaft Grounding Systems divert shaft current safely to the motor frame, away from the bearings, across the whole mill:
- CR Series: our axially mounted, sealed-brush system for standard NEMA and IEC frame motors. The right fit for most mill motors, from fans and pumps to smaller drive sections.
- SR Series: a split-ring system for large-frame motors, grounding both shaft ends where circulating currents are a concern, such as large paper machine drive motors.
- DR Series: a solid-ring system for motors that can be uncoupled, ideal for planned retrofits during a scheduled shutdown.
Why SGS Holds Up in the Mill Environment
Built to survive the mill floor.
The CR Series brush is sealed against the moisture, fiber, and chemical contamination that foul open grounding devices, so it keeps a reliable path to ground in the wettest, dirtiest parts of the mill. And because it’s field-serviceable, it can be inspected and replaced in under a minute while the motor runs, with no machine stop.
- Fast availability: same-day shipping within the US and rapid international delivery, so a protective part is never the reason a repair waits.
- Built for continuous duty: long service intervals and simple rebuild kits for motors that never stop.
- Proven and US-made: 40 years of shaft grounding experience, manufactured in the USA.
Whether you’re specifying protection into new mill motors or retrofitting the motors you already run, the CR Series installs in the field with handheld tools.
Keep Your Mill Running
Tell us about your paper machine, fan, and pump motors, and we'll recommend the right shaft grounding solution for your mill.