Failure analysis of a high-speed induction machine driven by a SiC-inverter and operating on a common shaft with a high-speed generator

Due to ongoing research work, a prototype test rig for testing high speed motors/generators has been developed. Its design is quite unique as the two machines share single shaft with no support bearings between them. A very maximum operating speed, up 80,000 rpm, was required. Because of need minimise vibration during operation at rotational speeds, rolling were used. To eliminate influence higher harmonics supply voltage and current on formation torque oscillations excessive losses in form heat, source inverter switching silicon carbide (SiC) power transistors characterizing precision output generation fundamental harmonic frequency several kilohertz During first start-ups, it turned out that system not stable, failure occurred. The paper presents consequences may arise when machine about 70,000 rpm fails. article contains pictures generator occurred speed.