New Cable Requirements for Large Wind Turbines

Wiring changes are looming for wind turbines.

The electrical systems on large wind turbines will soon be subject to a new standard, UL 6141, which could result in drastic changes to cabling practices. The standard applies to both new and refurbished wind turbines that generate more than 500 kilowatts of power. 

While UL 6141 has not yet been finalized, it proposes strict limits on the use of appliance-wiring material (AWM) within and between key generator subsystems.

The limits spring from a requirement that all accessible wiring must be either enclosed in a raceway or rated for tray cable usage. Since only UL listed cable offer the tray rating, AWM will no longer make the grade in many turbine wiring applications.

Here’s a breakdown of how the new standard will likely affect the different wind turbine subsystems:

Gearbox. There is no UL component standard specifically for gearboxes, so UL 6141 will apply to the wiring for gearbox components such as heaters and PT 100 temperature sensors.

Generators. The existing UL component standard for generators permits AWM cables under limited circumstances. To use AWM in generator wiring, there must be a ready-to-connect cable with connector. The generator must also be fitted with a grounding cable within the generator itself.  Since neither option is common with wind turbine generator manufacturers today, UL listed cable products will likely be the safest design strategy once UL 6141 comes to pass.

Tower. Since there is no UL component standard for the tower, UL 6141 applies. The proposed standard clearly calls for listed products for cables that run vertically up the tower—including those for power, control signals, lighting and hoists.

Drip Loop. Raceways are not commonly used in drip loops.  Assume that listed cable products will have to be used in this application.

To learn more about all the changes UL 6141 will bring, download our technical update.

Tips for Designing Cable Carriers

Of all the machine design details to worry about, cable carriers probably don’t top your list. Yet if you care about the reliability and uptime of moving machines, it pays to devote extra engineering attention to the carriers and the components within them.

A well-designed cable carrier will dramatically extend the life of cables and fluid power supply lines by protecting them from damaging bends, crimping, abrasive wear and crushing.

Unfortunately, some cable carriers are poorly-designed and can trigger the very same cable and supply line failures they were supposed to prevent, causing expensive machine downtime. The potential for failures can largely be avoided by following a collection of simple carrier design guidelines developed by our Systems Group.

Over the years, our engineers have designed, built and delivered thousands of populated cable carriers that have been implemented in a wide variety of servo and VFD applications on packaging, automotive and other industrial machines.

Here are some basic tips for designing populated carriers:

•         Calculate. Determine the minimum bend radius and clearances of all the components that will fill the carrier. Define the optimal carrier length and location of the fixed mounting points.

•         Weigh. Distribute the weight of the fill components within the carrier. Take the time to calculate the weights of individual components, and place the heaviest components on the outside of the carrier.

•         Influence. Consider the operating environment. Chemical exposures and thermal conditions can influence the design of cable carriers.

•         Divide. Split the carrier into separate cavities so the cables and hose can all move independently of one another.

•         Get Help. Involve your cable and carrier vendors in the design process. They work with carriers every day and can offer additional engineering expertise that will help you design a carrier that will go the distance.

For detailed engineering guidelines, download our technical paper on cable carrier design.

 

Common Electrical Compliance Questions

With UL requirements and NFPA standards each holding  sway over different aspects of electrical compliance, it’s always been tough to figure out whether your cable choices  will pass regulatory muster.

The job of picking compliant cables recently became even  tougher. A new version of NFPA 79, the main standard governing the electrical safety of industrial machines,  drastically changes the compliance picture. To read more about the changes and how they’ll affect your cable  selection practices, download our new technical paper on NFPA 79 compliance. And check out the following answers to your most commonly asked compliance questions:

is  NFPA a law?

No. NFPA–79 is the key electrical safety standard accepted by machine builders, installers and buyers in the United States.

Does a machine have to comply with NFPA79?

In most  cases, yes. The need for NFPA compliance ultimately depends on the application details and whether the machine is being installed in a building. When in doubt, it’s a good idea to comply with NFPA 79 to maximize safety and avoid the potential for litigation.

Will machine builders and buyers standardize on the new edition of NFPA79?

Yes. Concerns about safety and liability issues will force compliance with the new 2012 edition of the NFPA standard. Buyers of industrial equipment are unlikely to purchase non-compliant machines that could increase the potential for litigation.

Who decides which cables can be installed in the field?

Engineers may assume that UL dictates cable choice, but the real authority falls with electrical inspectors who determine compliance with the National Electrical Code. UL, however, does control the electrical, physical and environmental testing requirements and approvals that, in practice, determine cable usage in the field

are UL listed cables always allowable for use on a machine?

Not necessarily. There are machines that use UL listed cordage incorrectly. For example, some listed cables are only intended for temporary applications. Other listed cables may not meet the minimum stranding requirements needed for NFPA 79 compliance.

What’s special about MTW approval?

Machine Tool Wire (MTW) approval requires that the cable be flexible and offer a high degree of mechanical durability. These characteristics allow it to perform under the challenging conditions surrounding industrial machines.

Are all MTW cables oil resistant?

Yes, all compliant  MTW cables minimally meet the requirements of the UL Oil Res I test. For applications requiring a more severe exposure, the more rigorous Oil Res II test is also a permitted option.

Can I run MTW cable into building infrastructure?

No, not unless it is dual marked with the appropriate UL Listing. Cables marked “TC” offer the high flammability

rating needed for installation in building infrastructure. The MTW requirements alone mandate that a cable only meet a minimal flame test known as VW–1.

Can cables be left exposed when going from the machine to the cable tray?

In most cases, no. Cables designed for exposed runs must have a “TC-ER” approval

Call us today for all your wire & cable project needs

Toll free: 800-774-3539

Web: http://lappusa.lappgroup.com

Email: sales@lappusa.com

New Training Center to Benefit Students and Local Workforce

Historical Partnership with Shelton State Community College

New Training Center to Benefit Students and Local Workforce

The Lapp Center for Excellence in Cable Technology will provide Shelton State Community College in Alabama the ability to teach students the technical aspects of electrical cabling selection and installation.  

Understanding that students of today should be prepared to enter a global marketplace, it is important for them to utilize the National Electrical Code as well as International standards for wire, cable, and connector selection.  

The Lapp Center will provide a platform to teach students code standards, terminology and nomenclature used in the electrical cabling industry along with procedures for selecting the proper wire, cable and connectors for specific applications. 

In addition, students will train with industry standard tools and techniques using hands on activities to terminate wire and cable products in real world examples of residential, commercial, and industrial applications.    

Utilizing reference materials that are developed and furnished by the Lapp Group, college faculty will integrate all of the related information into the existing curriculum currently required for students enrolled in the Industrial Electronics and Electrical Technology programs of study.

 Read more at http://www.lappusa.com/shelton

 

Call us today for all your wire & cable project needs

Toll free: 800-774-3539

Web: http://lappusa.lappgroup.com

Email: sales@lappusa.com

 

CAT.6A Cables For Continuous Flex and Torsion Applications

CAT.6A Cables For Continuous Flex and Torsion Applications

 

CAT.6A cables already provide fast data transmission rates in industrial Ethernet systems. Yet these cables could not withstand the continuous flex or torsion requirements associated with moving machine applications. Our new ETHERLINE® CAT.6A cables remove this limitation.

In an industry first, the new ETHERLINE cables combine CAT.6A’s 10 Gbit/sec data transfer rates withcontinuous flex and torsion performance suitable for robotics, machine vision systems, wind turbines and other industrial machines with motion systems. 

 

Previous continuous flex industrial Ethernet cables offered a maximum data transfer rate of 1 Gbit/sec.To raise the bar on CAT6.A continuous flex performance, our engineers had to solve a tricky shielding challenge. CAT6.A cables operate at frequencies as high as 500 MHz, which predisposes them to electromagnetic noise and interference (EMI). A conventional shielding system capable of warding off EMI at these high frequencies would have made the cables too stiff for continuous flex or torsion applications. 

 

So our engineers created an entirely new shielding system that strikes a balance between EMI

protection, flexibility and the mechanical strength to withstand the high strains associated with continuous flex or torsion. This new shielding employs a proprietary wrapping process that wraps aluminum compound foil around individual twisted pairs at an angle optimized for shielding performance. 

 

In addition, the cable has a copper braid reinforced with a foil-laminated fleece.This high-quality screening, the first of its kind,ensures extremely reliable data transfer. 

 

ETHERLINE CAT.6A comes in two different versions, one optimized for continuous flex and the other for torsion. The continuous flex version is suitable for use in cable tracks and has been tested for morethan one million bending cycles.Available with either PVC or PUR jackets, both versions of the ETHERLINE CAT.6A offer: 

 

• Compliance to the PROFINET standard.
• Resistance to UV and flame.
• Performance in damp or dry operating environments.

 

New RJ45 and M12 x-coded connectors designed specially for ETHERLINE CAT6.A cables are also

available. 

 

 

 

For more information on ETHERLINE CAT.6A FD and torsion cables, visit www.lappusa.com/ethernetCAT