Comparison of Additive Balancing Processes for Rotors in the Context of High Speed Electric Traction Motors

In the ongoing development of electric traction motors with increasing volumetric power density, concepts are being developed for rotational speeds of more than 30,000 rpm. These motors require an especially high balancing quality. Due to the unavoidable material and production fluctuations, a tuning of the mass distribution regarding the rotation axis is necessary. This balancing can be achieved by subtractive or additive process alternatives. In this paper, an overview of current balancing approaches is given first. Based on this, the potentials and challenges of additive balancing methods, which directly apply material to the lamination stack, are explained. In this context, two joining processes, namely ultrasonic welding and laser beam welding, are examined in more detail on the basis of practical experiments. In particular, influences on the quality of the lamination stack are considered.