The objective of the present study was to deal with the rotordynamics of the rotor of an ultra-high speed PM type synchronous motor-generator for a 500 W rated micro gas turbine generator. This paper introduces dynamic analysis, and experiments on the motor-generator. The focus is placed on an analytical approach considering the mechanical dynamic problems. It is essential to deal with dynamic stability at ultra-high speeds. Unbalance response analysis is performed by calculating the unbalance with and without balancing using a balancing machine. Critical speed analysis is performed to determine the operating speed with sufficient separation margin. The unbalance response analysis is compared with the experimental results considering the balancing grade (ISO 1940-1) and predicted vibration displacement with and without balancing. Based on these results, a high-speed motor-generator was successfully developed.
Permanent Magnet (PM) type Longitudinal Flux Linear Motors (LFLMs) are electromagnetic devices which can develop directly powerful linear motion. This paper presents statistical optimum design of PM type LFLM to reduce the weight of the machine with the constraints of avg. thrust force using the penalty method with characteristics function and Response Surface Methodology (RSM). The contribution and effect of the each design variable on the characteristic function is evaluated by the analysis of means (ANOM) and optimum design set is determined. The reduced gradient algorithm is adopted in RSM. Therefore, it is expected that the proposed optimization procedure using penalty method and RSM can be easily utilized to solve the optimization problem with constraint of electric machine.
This paper deals with the natural frequency analysis and two experiments to evaluate first twisting and bending natural frequency of railway vehicle. The KS R 9228 testing method is generally performed as pseudo FRF(frequency response function) which is widely used by two accelerometers.The exciting method is utilized using the load weight(1 ton release). The modal testing is used to verify KS R 9228 testing result and the natural frequency analysis result. The first twisting and bending natural frequency should be above 10 Hz by resonance which is mostly generated between bogie and vehicle frame exciting low frequency. The first twisting and bending natural frequency of railway vehicle are successfully verified between analysis and test.
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