Roxtec seals cables on motor controllers

  • November 26, 2014
  • Case Study

November 26, 2014 - Meeting the demand of global customers is no easy task. Roeslein & Associates, Inc., based in St. Louis, is an engineering, fabrication and construction firm that specializes in modular systems. When building equipment for customers all over the world, the company uses Allen-Bradley ArmorStart distributed motor controllers from Rockwell Automation to provide conveyor control.

Roeslein’s global base presents challenges for its control systems due to the variation of applications and differences in cabling standards for each country. These variables present situations in which the firm often needs to add or remove cables in the ArmorStart. Roeslein says its customers often need more cables to bring in 3-phase and control voltage for new installations that a standard CGB could not provide. “The gland plate on the bottom of the ArmorStart has two round knockouts, and Roeslein needed one square hole,” notes Ray Hoelting, electrical engineering manager at Roeslein & Associates, Inc. “The high cost of the CGBs to perform this task, along with the issues of using a single-hole CGB for two cables, was a challenge,” he adds. To resolve these challenges, Roeslein had new gland plates laser-cut by a local fabricator, and asked Rockwell Automation Encompass Product Partner, Roxtec, a provider of cable sealing systems, to supply a flexible solution that could adapt easily to varying cable demands. The company’s EzEntry cable sealing system allowed for manageable wire installation into the ArmorStart motor controllers.   The Roxtec cable sealing system is designed to simplify cable sealing in the equipment manufacturing industry. It enables multiple pre-terminated cables of different sizes to be routed and sealed in one single frame opening. The seal has a lightweight composite frame with integrated gasket, and consists of a single-side installation with integrated compression. Hoelting says he chose Roxtec for its cable sizing flexibility. “Since we use different types of cable with varying jacket thickness, and in some cases varying gauges of wire, Roxtec gives Roeslein the flexibility without having to change part numbers all the time, allowing us to have a standard that will not change from project to project.” The adaptable design of Roxtec cable sealing systems offers flexibility to cover all of Roeslein’s projects, reducing engineering and procurement time. Bret Caywood, key account manager, Roxtec notes this standardization using the cable sealing frame enables Roeslein’s engineers to make small changes in diameters without having to wait for specifics and details from the design group. “With our cable sealing system, Roeslein has the ability to peel layers from the modules to adapt to larger power cable diameters, making it more flexible to different types of cabling used in different countries,” adds Bret Caywood. Using this flexible cable sealing system helped Roeslein meet the demand of its global customers, as the adaptable one-size-fits-all design allows the company to easily accommodate cabling standards of other countries. However, the company also reaped other benefits offered by Roxtec sealing solutions. “Our installation time is now cut in half — from 1 hour down to ½ hour per drive,” says Hoelting. “A typical system will have anywhere from 100 to 150 ArmorStart drives. Roeslein will assemble the custom gland plate and the cable sealing system ahead of time on an assembly line, which reduces the full installation time.” Caywood notes that using the sealing system also keeps out dust and helps ensure the safety of Roeslein’s equipment, and also helps ensure a better quality installation. “In the past, we would need to punch the CGB knockouts larger to fit the larger CGBs because of the cable we use. The issue arises when you are trying to punch the gland plate provided. This can cause warping and in some cases destroy the gland plate altogether. With this solution, we can ensure the environmental rating of the ArmorStart,” Hoelting explains. In addition, the solution eliminates rework caused by the wrong size CGB being used, further reducing installation time. Hoelting says the new system also has cut hardware costs, and replacement gland plates are no longer needed to replace warped or broken units, including incurred shipping costs for those replacements. “The decreased installation time in our factory and on-site translates into better utilization of labor for project work,” adds Hoelting.

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