Additional Losses of Electrical Machines under Torsional Vibration

Abstract

Electric drive trains have a torsional rigid-body vibration mode at a small, non-zero frequency. If an excitation occurs close to this frequency, the vibration amplitude may grow large and the electrical machine may suffer from significant additional losses. Standards set constraints on the oscillating torque in the shaft coupling and on the harmonics of line current. They indirectly limit the vibration amplitude and losses of the machines.