DHi® (Defense Holdings, Inc.®) of Manassas Park, VA has established a Core Exchange Program for Pitch Control Slip Rings used in GE1.X and Suzlon S88 WTGs. The program is currently limited to Stemman Slip Rings only, Models 6262151, 6262290, 6262875, or equivalent, serving the North American markets (U.S and Canada). Expansion to other markets will be considered on a case basis. The Program will be jointly administered by DHi and H&N Wind (H&N).
DHi entered the wind industry with its revolutionary Metal Fiber Brushes (MFBs) only 3 years ago under H&N's mentorship and considerable experience. Looking first to GE WTG's, Stemman slip ring carcasses were used under a program where H&N's customers would be provided refurbished slip rings using DHi's metal fiber brushes. The primary goal was to familiarize the industry with the multitude of benefits associated with DHi's metal fiber brushes. A secondary and very important goal was to demonstrate reducing Operations and Maintenance (O&M) costs and increasing operational availability when using slip rings incorporating DHi's MFBs. DHi's MFBs are high capacity current collectors that far exceed the capacity and service life of the originally installed Stemmann fingers. Under the initial program, Stemman carcasses that were salvageable were refurbished and retrofitted with DHi's MFBs on circuits 1-20, which required no periodic or preventative maintenance over the 3 year evaluation period. Circuits 21-35 retained the original Stemmann fingers and the associated periodic cleaning/lubrication requirements of the original unit.
With the metal fiber brush evaluation proven successful, our team is now providing DHi slip rings with exclusively MFB's for the GE 1.XMW Series (SSB/Non-ESS and ESS) and the Suzlon 2.1MW S88 WTG's. Amongst other benefits, HiPerCon® Brand metal fiber brushes are capable of operating without maintenance for the life of the turbine and can operate without concern in highly contaminated and oily environments. DHi's slip rings are designed to replace OEM pitch control slip rings in GE 1.X and 2.5 MW WTGs, Suzlon S88 2.1 MW WTGs, and Clipper Wind 2.5MW WTGs. Designs for other WTGs are easily accomplished.
DHi's HiPerCon® Brand Metal Fiber Brushes vs. Metal-Graphitic Brushes or 'Other' Fiber Brushes for Slip Ring Applications
DHi's unique patented Metal Fiber Brushes, or MFBs, were originally developed under Department of Defense funding for critical submarine nuclear power plant applications. MFBs, 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 other type brushes including carbon brushes, carbon-metallic brushes, and other metal type brushes. DHi's brushes provide superior current and data transfer, offering extended brush and slip ring service life of at least twice the service life of carbon and carbon–metallic brushes. They easily offer high current capacity of 250 amps/sq-in and significant decreases in acoustic, mechanical, and electrical noise at sliding speeds up to 100 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. The little wear debris that is generated tends to settle to the bottom of the enclosure where it doesn't cause problems and is easily cleaned up rather than being distributed throughout the enclosure and causing shorts, grounds, and other issues. DHi Metal Fiber Brushes are far less likely to damage the slip ring surface than carbon brushes, carbon-metallic brushes, or fingers. DHi Metal Fiber Brushes' silver alloy fiber also offers significantly better service life and higher sliding speeds over gold wire technology at a considerable price advantage. DHi's HiPerCon Brand MFB slip rings can be supplied as a form, fit, and function replacement to most existing slip ring designs, as demonstrated with the GE, Suzlon, and Clipper Wind WTGs. The long life, high reliability, and low maintenance of HiPerCon Brand MFBs make them ideal for wind turbine use on- and off-shore.
3 Year Assessment of HiPerCon
Brand Metal Fiber Brushes Validates Benefits in WTG Pitch Control Slip Rings
Rich Martin, DHi's President and CEO, states, "This three year assessment validates all our previous work in bringing this slip ring technology to the wind industry. The internals of the slip rings inspected looked brand new. Anyone who has ever experienced cleaning, lubricating, or replacing a slip ring can attest to the significant savings these brushes can bring to the wind industry in reducing operational costs and increasing profits. We are really excited to be working with H&N Wind in bringing our Metal Fiber Brush technology to the wind power industry. Our new slip rings with long life electric brushes offer up to a ten-year maintenance interval (cleaning/inspection only) 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 business that is dedicated to overcome the limitations of legacy brushes and slip ring systems. DHi is based in Manassas Park, VA with other facilities in VA and Trenton, NC. DHi has been ISO 9001 registered since 2003 and has received numerous awards from local, states, and federal government for outstanding technical innovation and performance.
About H&N Wind
H&N Wind, A Timken Brand Company, 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 parts and repairs including, but not limited to, generator, gearbox, slip ring, bearings, and electrical repair both up and down tower. DHi Pitch Control Slip Rings can be purchased by contacting H&N Wind at (800) 795-3537. Visit us at WINDPOWER 2014 in Las Vegas May 5–8, 2014 at the Mandalay Bay Convention Center, Booth #4259.