Statistical energy analysis of acoustic noise and vibration for electric motors: transmission from air gap field to motor frame

A large number of vibration measurements are performed on the stator of a standard 5.2 kW electric motor. The rotor and the end-caps are removed. First, vibration measurements are performed on the stator without coils, i.e. consisting of the stator yoke (ferromagnetic iron) and the motor frame (cast iron) only. Second, vibration measurements are carried out on an identical stator with a standard coil system in the stator slots. Subsequently, a statistical energy analysis (SEA) is performed using these experimental data, in order to quantify the internal losses in the stator yoke and in the coils. The SEA also allows us to quantify the transmission of vibrations from stator yoke to motor frame (coupling loss factors), and to consider the influence of the presence of the coil system.