Experimental Vibration Studies of a 10 kW 30,000 RPM High-speed Switched Reluctance Motor

A switched reluctance motor (SRM) is suitable for high-speed and high-temperature applications as its rotor does not have conductors or permanent magnets. This paper presents the vibration studies of various components and sub-assemblies of a 10 kW 30,000 rpm SRM. The main components of the SRM, like stator laminations (2071 Hz), rotor laminations (2244 Hz), shaft (906, 2381, 4375 Hz), and rotor laminations assembled on the shaft (sub-assembly) (893, 2118, 4075 Hz) are studied initially for their natural frequencies and mode shapes. The natural frequencies of the rotor sub-assembly are lower than its components. Additionally, when the rotor sub-assembly is assembled with an encoder (500 Hz) and bearings (2237, 2843 Hz), the modified natural frequencies are quantitatively obtained and reported. Similarly, the natural frequencies of the components of a cooling jacket assembly, namely, jacket (1906, 2218 Hz) and spacer (687, 806, 2125) are obtained and the modification of the natural frequencies in the assembled condition is noted (215, 725, 828, 1960, 2200 Hz). These results and investigations of the changes in natural frequencies of various components form the basic step in a bottom-up approach to condition monitoring of machines. The assessment of the natural frequencies of components and subassemblies allows for initiating preventive or corrective measures to reduce the structural vibrations during the operation of the SRM.