Cable alternatives for PWM AC drive applications

Abstract

This paper describes an alternative solution for cables used with insulated gate bipolar transistor (IGBT) variable frequency drives (VFDs). New IGBT technology has introduced voltage stresses on motors and cables that lead to unpredictable system performance and reliability. This paper includes a performance and cost comparison between a continuously welded armored option, the option of lead wire in conduit and a proposed shielded tray cable. Unique physical characteristics of the cables are discussed. A proposed cable with increased insulation thickness is discussed that insures long-term cable service life under VFD operation, while the shielded coaxial braid contains VFD EMI emissions. Other applications, options, and termination considerations with respect to the petrochemical industry are discussed. Cable performance is documented with theoretical and experimental support.