Optimized Electromagnetic Compatibility by New Motor Cable Design

Machinery and facilities with electric motors and numerous variable frequency drives (VFD) stimulate parasitic capacitive and inductive coupled leakage currents on cable shielding, ground conductor and common bonding networks (CBN) by pulse width modulation (PWM). This leakage currents could lead to severe malfunction of industrial machinery and neighbored infrastructure. By applying sine filters, shielding or by installing improved and meshed grounding networks solutions were found to mitigate the symptoms. In this paper, a novel cable design is introduced, which achieves full electromagnetic symmetry. By rearranging the cores with a special stranding process, electrical coupling drops to a minimum and inductive coupling is eliminated. This paper explains the cause and properties of capacitive and inductive coupled leakage current, electromagnetic interference (EMI) problems and their effects related to industrial applications. Furthermore, it shows how research based on EMI coupling paths and knowledge of constraints of conventional cable design led to the novel design approach. Finally, the new cable approach is proven against other state of the art cable types.