Slip rings tested for years of trouble-free operation

In response to demands for longer, uninterrupted service life, DEUBLIN Co. manufactures a complete line of electrical slip ring systems. These devices are used in many industrial applications such as wind turbines, tooling machines, plastic-molding machines, propulsion centrifuges, robotics, and others.

The company says its slip rings are optimized with material configurations tested and proven for hundreds of millions of cycles, which translates into many years of trouble-free operation with unsurpassed performance, significantly reducing down-time and maintenance costs.

The electrical slip rings feature flexible engineering to support unique requirements and allow for easy replacement of existing slip ring brands by the end user. DEUBLIN designs slip rings to a variety of EMI, operating temperatures, storage temperatures, acceleration, mechanical vibration, and mechanical shock requirements as required by the customer application. The company’s rotary union and slip ring combinations have a unique plug-and-play configuration to reduce installation and maintenance time. Other design innovations include slip rings that meet requirements such as RF shielding, mixed signal handling, high frequency impedance matching, reduced temperature generation, and miniaturization.

A slip ring allows transmitting power and electrical signals from a stationary to a rotating structure. Also called a rotary electrical joint, collector, or electric swivel, a slip ring can be used in any electromechanical system that requires unrestrained, intermittent, or continuous rotation while transmitting power, or data, or both. Typically, it is compromised of a graphite or metal contact brush which rubs on the outside diameter of a rotating metal ring. As the slip ring turns, the electrical current or signal is conducted through the stationary brush to the metal ring making the connection. A new Electrical Slip Ring brochure is available (#SR1104 US), that replaces the SR102 US.

DEUBLIN Co.
www.deublin.com

Partnership in design manufacture and distribution of slip rings to NA windpower market

A provider of parts and engineering services to wind power industry in North America and a manufacturer of wind turbine and custom components for motion applications worldwide, have announced their partnership in design, manufacture, and distribution of slip rings. UEA slip rings are said offer design versatility as component-kit rings or as completed, ready-to-mount assemblies with optional pre-wired harnesses. A wide selection of circuitry is available, with many combinations of amperage and voltage, ac or dc. The compact design is made possible by brushes stacked on alternating sides. UEA Slip Rings come in a variety of bore sizes, from 0.500 to 14.00 in. This approach translates into opportunity for Availon and UEA to develop more new aftermarket products.

Mark Hanawalt, UEA’s President, adds, “We manufacture custom-designed wind turbine slip rings that match exact customers specifications and are delivered in a matter of weeks.”

The partnership between Availon and Waverly, Iowa-based UEA will let Availon sell replacement components for aftermarket use in wind turbines. Stock will be kept in the Availon’s Iowa and Texas locations. The two companies will work together to facilitate the development of new UEA products and aftermarket solutions for many types of wind turbines.

Availon Inc.
www.availon.com

United Equipment Accessories
http://www.uea-inc.com/

Advantages of custom wire harnesses for slip rings

One option that sets UEA slip rings apart from most others manufacturers are its custom wiring harnesses. These harnesses are built in-house to attach to either or both the center leads from the center core stack and/or the brush leads or outer portion of the slip ring assembly. Adding plugs or connectors to the outer ends of the harnesses lets the slip-ring assembly become a ‘plug and play’ component of the customer’s complete electrical wiring system.

Harnesses assembly begins with discrete wires of the correct AWG size, voltage rating, environmental rating, etc. that are often color-coded to meet a specification. The harnesses may also include or be composed of one or more jacketed cables of the required size and ratings. Discrete wires in the harnesses are ink-jet marked with the circuit number to match the correct circuit in the slip ring and often a customer specified function for that circuit. These markings are spaced about every 2 in. along the length of the wire to make the circuit easily identifiable at any position along the full length of the harness. Wires and cables are cut to a length to meet customer specified overall lengths when attached to the slip ring, bundled for use in either the brush or center harness and supplied to the Harness Layout Department. If any one of a wide variety of connector types or brands is to be attached to the harnesses, the insulation is stripped from one end of the individual wires and terminals are attached or the wires are soldered to the connectors. At that time, individual wires from the connector, or connectors if the harness includes more than one, are put through individual holes in a ‘die’ which puts the wires in the correct order to match the center core leads from the core stack of rings and insulators, or to provide a more orderly ‘break-out’ of the leads to the brushes. As the wires are pulled back through the die, they are taped to keep the wires in a correct order. A twist is often added to the harness, retained by the tape, to make the harness more flexible. Some harnesses are supplied with only the taped covering but many also add a heat-shrink tubing jacket for better sealing or an over-braided nylon thread covering for increased abrasion resistance. Completed harnesses are then attached to their slip-ring assemblies and then to a test stand for complete continuity, shorting, and other required tests. At this time point, the harnesses with connectors becomes an advantage to UEA because they are more easily attached to the test stands using mating harnesses than would be assemblies with only individual wires on the harness ends.

– Brent Jensen, Director of Engineering

United Equipment Accessories Inc.
http://www.uea-inc.com/

Contactless sliprings pass tests

The manufacturer of industrial wireless power devices announced the successful trial of the Proxi-Ring 480, a contactless slip ring that provides wireless power and data to pitch-control systems in wind turbines. The Proxi-Ring 480 is said to make wind-energy generation more cost-effective by increasing uptime and reliability and eliminating costs of maintaining and replacing mechanical slip rings.

“Our contactless slip ring has been working flawlessly ever since installation in a hydraulic wind turbine in Spain eight months ago,” says VP PowerbyProxi Fady Mishriki. “It replaced a mechanical slip ring that was causing problems several times a week and this frequency was increasing as the turbine aged. The faults are hard to diagnose due to their intermittent nature and because turbines are stationary when tested. We set out to prove our wireless device delivers significant benefits over mechanical slip rings and we’ve done that.”

“The plug and play Proxi-Ring 480 was easy for our technicians to get working in the 1.3-MW turbine and it has performed perfectly,” says Jose Rodriguez, Managing Director of IM FutuRe, an O&M company. The slipring passes the required level of power and communication signals wirelessly and without friction. Proxi-Rings allow 360◦ continuous rotation and are corrosion-resistant and waterproof. Unlike mechanical slip rings they require no cleaning or maintenance because contaminants such as oil or brake dust do not affect operation.

PowerbyProxi

www.powerbyproxi.com

Wind Turbine Reliability – The Importance of Highly Reliable Pitch Control and Blade Sensing Systems

In this 40 minute webinar, learn how two common hazards can hamper a wind turbine’s production. Wind-turbine owners and operators may experience a significant reduction of generated power, reducing overall turbine efficiency, if they don’t take into account:

• Blade Icing

• Failed Slip Rings Issues
• Increased Reliability

In this free webinar, we explore how Moog Blade Sensing Ice Detection Systems can monitor the load of each blade, providing real-time data indicating presence and level of ice build-up. We also examine key challenges with transmitting power and data signals from the nacelle through slip rings to the pitch-control system. Costly downtime can be eliminated by using fiber-brush technology and rugged mechanical components in the slip ring. Moog representatives show how they designed a slip ring that addresses these requirements for reliability and maintainability and thereby reduces a wind turbine’s overall operating cost.

Trends in sliprings

Sliprings work in the turbine’s hub where they transmit power and signals from stationary cables in the nacelle to rotating equipment in the hub. A slip-ring assembly is often a graphite or precious metal brush that contacts the outside diameter of a rotating metal ring. As the ring turns, electrical current or signal is conducted through the stationary brush to the metal ring making the connection. Additional ring-brush assemblies are stacked along the rotating axis for more electrical circuits.

In pitch slip rings, the trend in new designs is on two fronts. “First, as turbine designs increase in power output and size, the demand on the pitch slip ring is higher power transfer,” says Moog’s Senior Business Development Manager Steve Black. “Second, data handling and signal demands are increasing to provide additional condition monitoring in the hub.  It is critical that the contact technologies be durable enough to handle power peaks at the extremes of operation.”  Equally important is a need to protect data lines from potential cross talk with power lines.

Another trend is toward more complete pitch controls. “These would include hub controls, pitch drive motors, power back-up, blade monitoring, and the slip ring to transfer the power and control signals through the rotary interface,” says Black. The company supplies complete systems to the OEM and also offers aftermarket pitch slip rings to improve system performance.

Also look too for new pitch control slip rings in the aftermarket. “The wind turbine service market is growing tremendously as the turbine population ages and asset owners are look for ways to control maintenance costs and maximize turbine availability and output. Products should be able to replace slip rings in older turbines with long-life, high-reliability design to provide pitch slip rings that can operate for years without maintenance.

“Ideal pitch slip rings should be installed and forgotten. Many designs in use today require periodic maintenance to clean away wear debris, flush out oil and dirt, and relubricate. Often replacement of the entire slip ring is done too frequently.  Keeping the turbine technicians out of the nacelle will keep costs down and outputs up.  That is the goal for asset owners and the focus of efforts in the aftermarket portion of our wind energy business.

The high-reliability quest has let some companies devise non-contacting slip rings. One is an inductively coupled power transfer device. Inductive-power transfer applies the scientific principle of electromagnetic inductance. The manufacturer of one says its sliprings work at high efficiencies by using wireless power transfer that can harmonize itself in the field. This makes the systems resistant to changes in real world environmental conditions and load variations, says developer New Zeeland-base PowerbyProxi.

For wireless power, transmission distances can reach to 6 to 8 ft, but efficiency levels between transmitter and receiver are low. Commercial applications in which transmission distances are less than 8 in. allow efficiencies over 90%.

Power transmits as a single load while a built-in data-communications system switches power, for example, to meet different device requirements of wireless receivers. In this way, the slip rings provide wireless power and data to pitch control in wind turbines, improving wind turbine efficiency by reducing the cost of maintaining and replacing existing mechanical slip rings and their carbon brushes. Any size turbine can be supported, says the company.

Slip rings ready for demanding apps

Slip rings for a wide variety of industrial applications come from Deublin Co., Waukegan, Ill. The devices are easily configured for both power connections and signal connections. The signal portion of the slip rings is compatible with Ethernet, Profinet, RS-232, RS-485, RS-422, CAN as well as generic analog or digital sensing and 24V control signals.

Slip rings are well suited for a variety of demanding applications such as wind turbines, robotics, industrial machinery (textile, bottling, and packaging for example), test equipment, commercial displays, crane and hoist controls just to name a few. Deublin Company has used the same high quality standards in the development of the new Slip Ring product line as we have established in our rotary union designs for over 60 years.

The electrical device allows transmitting power and electrical signals from a stationary to a rotating structure. A slip ring can be used in any electromechanical system that requires unrestrained, intermittent or continuous rotation while transmitting power and/or data. Typically, a slip ring is comprised of a graphite or precious metal brush, which contacts the outside diameter of a rotating metal ring. As the ring turns, electrical current or signal is conducted through the stationary brush to the metal ring making the connection. Additional ring/brush assemblies are stacked along the rotating axis if more than one electrical circuit is needed. A new brochure, Catalog SR084 US, is available along with a Request for Quote form that assists in specifying a slip ring.

Take a look at Deublin’s Slip Ring catalog here

Wind Turbine Torque limiter by Centa

CENTA produces an enhanced version of its Torque Hub, the slip clutch which offers a simple and low-cost design for torque overload generator protection.

In wind power plants, electrical circuit problems are known to cause short-term torque peaks. In this event, slip clutches protect the costly gearbox against overload by slipping at a defined maximum torque in order to temporarily interrupt the drive.

The slip process takes place not on the generator shaft surface, but inside the CENTA Torque Hub, which is mounted on the generator shaft in the coupling’s clamping set.  CENTA’s latest development in slip systems-”CENTA Torque Set”-now positions the slip unit to the middle section of the shaft. By relocating the slip function, manufacturing tolerances at the generator shaft no longer cause variations in the slip torque, resulting in improved accuracy of the slip function.

Another advantage of the new design is that the slip system is made to be pre-mounted as a complete unit. The maximum torque is set on a certified test bench according to the manufacturer’s requirements and documented in a test report, eliminating the need for on-site adjustments.  The low-maintenance slip system is also designed to allow for multiple slip processes (> 200) without having a major impact on the slip torque setting. Depending on the size, a torque range of up to 120 kNm is covered. The new slip system can also be provided as a low-cost system component which does not include the coupling unit.

Moog slip rings replace an existing design

A recent slip ring design, which is also a direct replacement for the pitch-control slip ring on GE 1.5 MW series wind turbine, comes from Moog, East Aurora, NY.

The AC7008 slip ring provides reliable transmission of power and data signals for the rotating blades from the control system. The advantage of the recent design over traditional models is its performance in harsh environments. For instance, fiber brushes and reliable mechanical components in the new unit eliminate costly downtime.

The AC7008 slip ring operates maintenance free for over 100 million revolutions. What’s more, it does so without lubrication and over a wide range of temperatures, humidity, and rotational speeds. The slip ring is protected from the environment and sealed to an IP54 rating.

Key pluses for the design include:

• Maintenance free for over 100 million revolution
• Minimal generation of wear debris
• No lubrication required
• Wide operating temperature range
• Lower life cycle cost
• High reliability

Moog
moog.com/wind

Slip rings for wind turbines

Moog Components Group has announced the introduction of a new slip ring that is a direct replacement for pitch control slip rings on the GE 1.5 MW series wind turbines.

The AC7008 slip ring provides reliable transmission of power and data signals from the nacelle to the control system for the rotary blades. The advantage of this slip ring over traditional models is its performance and quality in harsh environments. Costly downtime is eliminated by utilizing fiber brushes and robust mechanical components in the slip ring design.

The AC7008 slip ring operates maintenance free for over 100 million revolutions. A unique feature of the fiber brush technology is its ability to achieve long life without lubrication over a wide range of temperatures, humidity and rotational speeds. In addition, the fiber brush has the capability to handle high power while at the same time transferring data signals.

Moog has long recognized the value of fiber brushes for long life, space efficient slip rings. Moog’s patented approach has led to hundreds of different slip ring designs for a variety of challenging applications – from satellite solar array drive power transfer to industrial packaging equipment.

Key Advantages of the Slip Ring:

-Maintenance free for over 100 million revolutions
-Minimal wear debris generation
-No lubrication required
-Wide operating temperatures
-Lower life cycle cost
-High reliability

The Moog AC7008 slip ring provides direct connection to the gearbox with wire terminal connections in both the stator and rotor junction boxes. Each unit is shipped with a heater installed. The slip ring is protected from the environment and sealed to an IP54 rating.

Moog Inc.
www.moog.com/components