| Abstract |
High frequency bearing currents are a parasitic phenomenon that affects inverter-fed induction machines, causing damage and wear to the mechanical bearings, which might lead to unexpected failures, increase of the machine downtime and reduction of its lifespan. This paper describes how the bearing currents are affected by changes in the components of the electrical circuit that feeds the induction machine. The referred system consists of: Two-level voltage source inverter, different passive filters (a) common-mode ring filter, b) common-mode ring filter with small phase-to-ground capacitances, c) differential mode filter, d) dual-mode filter and e) du/dt-filter), different motor supply cables (shielded vs. unshielded cables with lengths_of_50_m, 150_m or 300_m) and the two different induction motors (rated power of 11_kW and 15_kW, respectively). So, in total sixty system arrangements were tested. The highest reduction of bearing currents was measured with the dual-mode filter in all cable configurations. |
