By Phil Burgert
Size and heat dissipation are continuing issues that panel builders confront every day. Controlling these factors is a continual focus of device vendors, and they have suggestions on how these goals can be achieved.
With rising commodity prices and skilled labor at a premium, control panel builders are trying to improve device density and make the best use of both money and space, observes Bill Bardsley, market segment manager for the North American control panel builder operating division of Schneider Electric. He recommends the use of approved busbar-configurable devices such as power distribution panelboards for branch circuits. “You can increase component density and reduce labor cost,” says Bardsley. “Using power distribution lugs on a breaker rather than a power distribution block can save space and wiring labor.”
Additionally, he suggests looking at International Electrotechnology Commission (IEC) application-rated devices. “Remember, smaller might not be better, but can be just as good,” says Bardsley.
Heat dissipation is a big issue to be addressed in panel building, too. Bardsley says heat inside a control panel can be harmful, so every effort should be made to try to remove it. “A key point to remember is to not fight convection,” he states.” Since heat rises, it is important to put more sensitive products at the bottom and critical product next to the inlet or exhaust vent.”
Other suggestions for heat dissipation include making the vent filters easily accessible so they can and will be changed, as well as remembering that a heat shield goes a long way on a rooftop in the summertime.
Enclosure manufacturer Hoffman recommends inclusion and use of thermal management systems, including air conditioners, fans, vents and heat exchangers, for most control panel building projects.
Another tip from Hoffman is to keep components accessible yet protected. With electronic devices commonly located in busy industrial environments, the components must be housed in an enclosure that protects against environmental contaminants such as dust, dirt and other debris.
Enclosures also are available to protect against harsh chemicals and ultraviolet rays, as well as electromagnetic inference and radio frequency interference. If the components must be accessed frequently for maintenance, select an enclosure with removable panels, data interface ports or double-hinged doors, along with the appropriate mounting configuration for the application.
Jeff Thornton, Red Lion product manager, advises that builders take advantage of today’s smaller but capable panel meters. “Saving panel real estate can provide a significant cost advantage, and a simple way to do this is to select a space-saving panel meter,” he says. “A smaller-sized meter can result in a more cost-effective panel, and this could be key to getting the sale. Panel meters continue to shrink in size while they maintain the same capabilities and allow panel builders to select a meter with a smaller display and depth to design a more cost-efficient panel.”
Thornton also says builders should switch the power source to reduce panel heat. One way to address this issue is to switch the primary power source in the panel from AC to DC to reduce the risk of electrical interference, since both power and control wiring are operating on a much lower voltage. DC voltage also can eliminate the need for transformers, which generate significant heat.
Derek Sackett, lead product marketing specialist for the Interface line at Phoenix Contact, suggests that analog devices provide an opportunity to save significant space and money in control cabinets. “Many manufacturers now make analog isolators 6 to 8 mm thin,” he says. “Just a few years ago, it was difficult to find any less than 12 mm, and most were typically 22 mm or more. Comparing our older modules and the newer 6.2-mm modules, I calculated a 17 to 50% energy savings, and cost savings in the same range.”
Sackett notes that depending on the application, space savings can range from 100 to 300%. Other savings produced by this type of switch include environmental benefits resulting from energy and material saved in producing, packaging and shipping the modules and final assemblies, says Sackett.