Applying arc resistant technologies to medium voltage variable frequency drives

Arc resistant low/medium voltage switchgear and motor controls continue to provide proven levels of additional personnel safety in most every petroleum and chemical facility. The Institute of Electrical and Electronics Engineers (IEEE) and International Electrotechnical Commission (IEC) generated testing guides and standards for these products which are open to some level of interpretation when applied to products other than traditional medium voltage circuit breaker or fundamental motor controller structures for which the current available standards and guides were intended when they were initially written. All medium voltage variable frequency drives, because of their inherent designs, require high volumes of cooling air which pose a real challenge in regards to providing full arc resistant capabilities and compliance to the present testing guides, procedures, and standards. This paper will deliver real solutions to this problem through the application of unique cooling processes, arc channeling technologies, structural enhancements, arc fault energy limiting methodologies and special application considerations when applying arc resistant medium voltage drives.