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MANASSAS PARK, Va., Sep 27, 2011 (BUSINESS WIRE) -- DHi(R) (Defense Holdings, Inc.(R)) of Manassas Park, VA has received a contract from H&N Electric, Pasco, WA for six long-life, low-maintenance wind turbine blade pitch control slip rings. These advanced wind turbine slip ring systems feature Stemmann units refurbished and remanufactured to incorporate revolutionary HiPerCon(R) Metal Fiber Brushes (MFBs). While other components of the slip ring require annual lubrication, these new electric brushes are capable of operating for up to 5 years without maintenance. The new wind turbine slip ring is designed to replace the OEM blade pitch control slip ring in a GE 1.5MW wind turbine. The first DHi refurbished and remanufactured wind turbine slip ring using HiPerCon's long life electric brushes was installed in May of this year at the PacifiCorp Leaning Juniper Wind Farm near Arlington, Oregon and has operated flawlessly in the wind turbine since being installed.
Metal Fiber Brushes vs. Carbon Brushes or Metal-Graphitic Brushes for Slip Ring Applications
Metal Fiber Brushes, which gain their name from the fact that they are
electric brushes constructed of thousands of hair-fine silver alloy fibers running on their tips, offer significant improvement over carbon brushes and carbon-metallic brushes in both data and current transfer, offering extended brush and slip ring service life of at least twice the service life of carbon and carbon--metallic brushes, high current capacity of 250 amps/inch(2), and significant decreases in acoustic and electrical noise at sliding speeds up to 70 meters/second. These long life electric brushes produce 80% less wear debris than solid brushes and require ZERO lubrication reducing the need for expensive maintenance and reducing the potential for short circuits and grounds. Metal Fiber Brushes, with their low spring force, are far less likely to damage the slip ring surface than carbon brushes or carbon-metallic brushes. Metal Fiber Brushes' silver alloy fiber offers significantly better service life and higher sliding speeds over gold wire technology at a considerable price advantage. HiPerCon(R) MFB slip rings can be supplied as a form, fit, and function replacement to most existing slip ring designs, as demonstrated herein. Their long life, high reliability, and low maintenance make them ideal for wind turbine use.
Metal Fiber Electric Brushes Are Designed to Outperform Traditional Carbon Brushes.
DHi originally developed Metal Fiber Brush technology under the Small Business Innovation Research (SBIR) Program working with HiPerCon, LLC, the U.S. Navy and the University of Virginia. Metal Fiber Brushes have been retro-fitted to slip rings in a large portion of the Navy's nuclear submarine fleet, are in testing for various slip ring applications in fixed wing aircraft and helicopters, and are being used for other commercial applications including shaft grounding brush systems where shaft bearing protection or long life electric brushes are needed.
Long Life Electric Brushes for Wind Turbine Applications
H&N Electric is a member of NAWSA (North American Wind Service Alliance), which is North America's only integrated wind turbine service network dedicated to providing efficient and professional repair service for wind powered engines.
Rich Martin, DHi's President and CEO, states, "We are really excited to be working with H&N Electric and the NAWSA group of companies to bring our Metal Fiber Brush technology to the wind power industry. Our new and remanufactured slip rings with long life electric brushes offer up to a five year maintenance interval (cleaning/inspection) and at least 200 million revolution Metal Fiber Brush service life."
Founded in 1994 and originally operated as Noesis, Inc., DHi is a privately-held, service-disabled, veteran-owned, minority-owned, small business that works with customers to overcome the limitations of conventional carbon brushes and carbon-metallic brushes and slip ring systems. DHi is based in Manassas Park, VA with other facilities in Charlottesville, VA and Trenton, NC. DHi has been ISO 9001 registered since 2003 and has received awards from the local, state, and federal government for outstanding technical innovation and performance.
H&N Electric specializes in working with customers on solving problems inherent with wind turbine generators and their associated components and provides a wide range of wind turbine repairs including, but not limited to, generator, gearbox, slip ring, bearings, and electrical repair both up and down tower.
| Product Model | Inside Diameter | Outside Diameter | Thickness |
| 47487R/47423 KOYO | 69.85 | 120.65 | 32.545 |
| 47487R/47420 KOYO | 69.85 | 120 | 32.545 |