Defense Holdings, Inc. (DHi) is raising the bar for the wind industry, having recently received unrestricted certification from Underwriters Laboratories (UL) for its pitch-control slip rings with HiPerCon metal fiber brushes.
With this significant accreditation, DHi becomes:
- Only the second company to achieve a UL listing for WTG pitch slip rings,
- The first and only company to achieve UL certified and listed WTG pitch slip rings using metal fiber brush technology,
- The first company to achieve UL certification for multiple OEM designs,
- The first company to achieve UL Type 1, 5 and 12 pitch slip ring enclosure ratings,
- The first company to achieve UL certified slip pitch rings with primary power circuit ratings up to 130KVA, and
- The only company providing U.S. manufactured pitch slip rings using metal fiber brushes.
DHi’s UL certified pitch-control slip rings are currently available for use in all GE1.X, GE2.X and Suzlon S88 WTGs. This series of pitch slip rings are pre-certified to provide design flexibility for current and future slip ring demands for other OEM designs, and are capable of incorporating many other features including: high-quality multi-GigaBaud signal transmission capabilities (>100MBPS/channel), high-quality transmission of signal over power (PLC requires capable monitoring and control methodologies), and other aftermarket needs (such as blade de-icing or tip illumination, and advanced blade monitoring and control).
DHi entered the wind industry with its patented Metal Fiber Brush (MFB) technology in the spring of 2011, under the mentorship of H&N Wind (a Timken Brand Company). Due to the general lack of knowledge throughout the wind industry of the existence and nature of DHi’s HiPerCon Brand MFBs, legacy pitch slip ring carcasses were used in a program through which customers were provided slip rings refurbished with DHi’s metal fiber brushes. The primary goal was to familiarize the industry with the multitude of benefits associated with HiPerCon brand patented metal fiber brushes as compared to carbon-based, metal-graphitic, or other metal brush technologies in use at that time. A secondary and very important goal was to demonstrate reductions of operations and maintenance (O&M) costs and increased operational availability.
HiPerCon brand metal fiber brushes vs. Metal-graphitic brushes
DHi’s unique, patented metal fiber brushes (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.
Amongst other benefits, HiPerCon brand metal fiber brushes are capable of operating without maintenance for at least 200-million revolutions, and can operate without concern in highly contaminated and oily environments thus offering extended service life over others in the industry. DHi’s brushes provide superior current and data transfer, and extended brush and slip ring service life.
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.
The long life, high reliability, and low maintenance of HiPerCon brand MFBs make them ideal for wind turbine use on- and off-shore. In addition, they are currently being used in super-conducting applications (up to 2,000 Amps/in2), in aerospace applications for de-icing and advanced blade monitoring and control, and in hydro-generation applications.
HiPerCon brand MFBs obtain certifications for UL 508 and CNS 22.2 No. 14
Rich Martin, DHi’s President and CEO, states, “We are excited to set new industry benchmarks by becoming the FIRST company in the world to provide the FIRST unrestricted UL certified CARBON-FREE slip rings to the wind industry. This validates five years of work in bringing our HiPerCon brand metal fiber brush technology to the industry.”
He continues: “Anyone who has ever experienced the frustration of down-time due to pitch control slip ring issues; cleaning, lubricating, or prematurely replacing a slip ring; can attest to the significant savings which DHi’s slip rings bring to the wind industry. In addition to this significant accreditation, which raises the bar for the wind industry’s selection of innovative technologies over legacy carbon based systems, we continue to work with customers seeking solutions to their systems via retrofit applications. Examples include the GE 1.X series DFIG and the Siemens pitch signal system. The bottom line is, with metal fiber brush technology proven in the field, why should anyone in the industry settle for anything less?”
Visit DHi at WINDPOWER 2015 in Orlando May 18-21, at the Orange County Convention Center, Booth #5319.
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