Arc-resistant motor control equipment

This article outlines the added benefits of arc-resistant medium-voltage (MV) motor-control equipment along with the details surrounding the appropriate installation and site-application considerations when arc- resistant MV control products are being considered. A case history is also included, where arc-resistant MV motor-control equipment was installed at a North American production facility of a large chemical company. Failure within a piece of MV control equipment, whether from a defect, an unusual service condition, lack of maintenance, or maloperation, may initiate an internal arc. Standards and guides have been developed over a period of many years through the cooperative efforts of users, those who specify equipment, manufacturers, and other interested parties to evaluate the ability of a given design to withstand fault conditions. These test conditions were traditionally representative of downstream events, referred to as bolted faults, that simulate a short-circuit condition outside the equipment under test.