A third Intelligent Motor Control highlight for this year is expanded features in Rockwell Automation's IntelliCenter v.4 software, which supports the company's line of Centerline motor control centers (MCC). Gama defined it as an "intelligent MCC."
MCC Monitoring Moves to the Control Room
IntelliCenter software provides a window into the MCC with real-time diagnostics and MCC documentation. It provides graphical views of individual MCC units, displays device data and views of any critical status information. Built-in networking captures information that aids predictive maintenance, process monitoring and some advance diagnostics. It reduces installation time with plug-and-play setup and will help minimize downtime by providing intelligent diagnostics and predictive failure information.
"We have a global offering of MCCs, applicable regardless of region or IEC or NEMA preferences," Gama said. "Safety and integration are big aspects of this for 2012, especially since we have included EtherNet/IP." In many plants, he said, the maintenance people will track the performance of MCCs, but not from the control room. They try to have an independent monitoring of the electrical system.
"What formerly would require you to get into the electrical control room all the time to see what's going on, which itself might require special protective wear and special authorizations, now can be monitored from a remote location with IntelliCenter software via EtherNet/IP," Gama says. "An optional energy module provides an energy report of consumption of each individual motor starter." All of the MCC information is available to the plant information layer via the Logix controller and EtherNet/IP.
"There also are safety enhancements available in our MCCs that aren't brand new, but are important," Gama added. "The most recent feature we've rolled out is SecureConnect. You can disengage your power buses before you open the door of the MCC. This ensures that the starter sequence inside that compartment has been completely disengaged from the electrical bus."
Arc Flash Safety Measures Enhanced
A second safety feature in the design and construction of the MCCs is ArcShield. "It ensures that if an arc happens, the safety of the personnel around the panel won't be compromised," Gama said.
IEC Centerline 2500 MCCs with ArcShield have no front ventilation; the pressure-relief vent system exhausts gases through the top of the enclosure, away from personnel. Arc-resistant latches on all doors provide pressure relief to keep the door to the MCC latched during an arcing fault; insulating covers on horizontal bus closing plates help prevent burn-through from arcing faults in the horizontal bus compartment; and arc-free zones provide areas within the MCC where it is not possible to apply an ignition wire without destroying the insulation.
Arc resistant baffles for NEMA Centerline 2100 MCCs with ArcShield let you have an arc-resistant MCC with a wider range of MCC units—even units that require venting, such as variable-frequency drives (VFDs). Arc-resistant baffles allow airflow to help dissipate the heat and still provide Type 2 accessibility, as defined by IEEE C37.20.7-2007. They help to shield personnel from the effects of an internal arcing fault on the front, rear and sides of the enclosure and also have arc-resistant latches on all doors. There are arc-resistant baffles in the full range of MCC units, and recessed horizontal bus and labyrinth vertical bus support to help prevent arcs from spreading between phases.
"So there are many design and construction factors to mitigate arc flash," Gama said, "but an important takeaway is that we test low-voltage MCCs to the same high-resistance standards as medium-voltage devices. That provides a very robust product."