Servotecnica S.p.A. represented by Heason Technology, offers a range of slip ring assemblies that are particularly suited for power and signal transfer from the rotating nacelle to the fixed tower on small-to-medium sized wind turbines. As the demand in this important area of green power grows, solutions which reduce maintenance and prolong working life and performance over time become increasingly important. To combat these factors Servotecnica has developed its SVTS series that feature a novel fibre bundle technology using precious metals that provide exceptionally long life when compared to traditional wear-prone carbon brush types used by other manufacturers. Furthermore, the fibre bundles require no lubricants, produce only negligible debris and greatly reduce need for routine servicing or frequent brush replacement through preventative maintenance.
A further benefit is much improved signal quality as the gold-alloy fibre bundle technology is arranged with multiple points of contact per circuit (up to 10) with each fibre individually in contact. This superior technology also maintains a much higher capacity to withstand transient overloads generally around twice those handled by slip rings with carbon brushes. Three main SVTS slip ring designs from the Italian motion control specialist apply to small-to-medium wind turbines, providing transfer up to several kilowatts as well as low-noise and low-crosstalk millivolt level instrumentation signals.
For instrumentation signals and lower power transfer up to 240 VAC, the compact A-series offers from 3 to 56 circuits in a housed design from 12 to 25 mm outside diameter with leadwire connection and optional IP67 protection. For sensitive instrumentation such as sensors and transducers typically used on wind turbines, the precious metal fibre bundle contact minimise noise and interference between the rings, allowing high data rate and high-frequency signal transmission.
The mid-range B-series is also a housed design for use to 20 A and 400 VAC - with an outer diameter range from 32 to 45 mm with faston terminal contacts plus a fully sealed IP65 option. They are specially designed for intensive use at high speed and for transmitting power and sensitive signals. The high power E-series is an open ‘naked’ design for power transfer to 60A and 400 VAC, with a through hole from 25 to 60 mm that may be used for other services. Again, fully able to handle sensitive instrumentation signals, an alternative capsule-unit with an IP65 sealed housing is also available.
These design options allow maximum flexibility when sizing up smaller wind turbine applications. Each of the SVTS series mentioned above features an individual and modular design that allows cost-effective selection of the electrical specification and number signal and power circuits required.