Electrical design of high-speed induction motors of up to 15 MW and 20000 RPM

This paper presents the electrical design of high-speed two-pole induction motors with a solid rotor cage design covering a power range of 2 to 15 MW with rotational speeds of up to 20,000 RPM. The electrical design and the underlying construction are explained, focusing on the rotor and on effects in high-speed motors related to the high basic supply frequency. Most modern calculation tools and procedures such as two-dimensional finite difference time-stepping calculations are used to predict the operational behaviour of the motor and to optimise the design. Based on these detailed simulations, simplified motor models are developed for the evaluation of design modifications as well as for daily design purposes. Finally, the calculation results are compared with test field measurements of a pilot unit with a power of 10 MW and a rotational speed of 12000 RPM. During an extensive testing period of 8 months the drive system was tested in the authors´ test field under various conditions. Tests were made up to full speed and almost full load. The measured results show excellent correlation with both analytical and numerical simulations. The drive system has worked very satisfactory and the drive system as well as its components, high-speed motor and converter, have been validated.