Company history Sohre

Sohre - A leader in the industry for over 50 years

John S. Sohre, P.E., pioneered research and led the way to a deeper understanding of shaft currents. Until John Sohre published his research on shaft current damage, there was no satisfactory explanation for the cause of certain types of damage observed in bearings, seals and gears. In 1971, John Sohre founded Turbomachinery® Inc. to provide advice on dealing with electrostatic and electromagnetic problems in power-generating turbines - problems that were becoming more common as machines increased in power and aged in the 1950s and beyond. In 1978, at the urging of customers, John Sohre designed, developed and began production of what has evolved into a patented line of shaft brushes for turbomachinery used in many industries around the world today. These brushes help to dissipate and monitor electrical shaft currents with a level of effectiveness and resilience unmatched by any other grounding device.

Electrostatic and light electromagnetic problems were already evident when the very first turbines were put into operation. However, with increasing power, electrostatic and electromagnetic problems have also increased. Arc welding, magnetic particle testing and other techniques that leave strong residual magnetic fields triggered an epidemic of severe shaft current problems in the past. These in turn led to significant operational losses in the process and energy industries. Reliable and suitable shaft brushes or demagnetization processes did not exist at the time. For this reason, Sohre Turbomachinery® Inc. was founded to address and solve these problems both in theory (through several published research papers) and in practice (by developing a more useful type of grounding brush for the turbine shaft).

The first Sohre brush was developed in the late 1960s to control massive and epidemic failures of turbine-driven turbocompressor trains caused by self-induced stray electromagnetic currents. Later, the LW-M1 grounding brush was developed for the U.S. Navy and its highly critical propeller shaft applications. Similarly, the Type-LW-STD (standard) was developed on request for a power utility and has been available since 1992.

Sohre products have been exhibited at the Texas A&M University Turbomachinery Symposium since 1993. A major paper entitled "Shaft Riding Brushes to Control Electric Stray Currents" by John S. Sohre, P.E., was presented that same year at the 20th Turbomachinery Symposium at Texas A&M University in Dallas. Since 1978, Sohre Turbomachinery® Inc. has sold more than 8,000 shaft grounding brushes worldwide, both for OEM installation and field retrofits. Several turbomachinery manufacturers now offer Sohre brushes as standard equipment.