DHi Implements Core Exchange Program for GE and Suzlon Wind Turbine …

January 28, 2014 by  
Filed under Wind Energy Tips


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 HN Wind (HN).

DHi® entered the wind industry with its revolutionary Metal
Fiber Brushes (MFBs)
only 3 years ago under HN’s mentorship and
considerable experience. Looking first to GE WTG’s, Stemman slip ring
carcasses were used under a program where HN’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
(OM) 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 HN 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

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

About HN Wind

HN 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 HN Wind at (800)

Visit us at WINDPOWER 2014 in Las Vegas May 5–8, 2014 at the Mandalay
Bay Convention Center, Booth #4259.

Rich Martin (DHi)
Voisin (HN Wind)

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