Localized bearing faults exhibit specific repetitive vibrational patterns. Due to the constant angular distance between the roller elements, the vibrational patterns occur on regular angular intervals. Under constant operating conditions such patterns become easily detectable as “periodic” events. Slippage or small variation in rotational speed are commonly modeled by introducing normally distr...

Based on the combination of improved Local Mean Decomposition (LMD), Multi-scale Permutation Entropy (MPE) and Hidden Markov Model (HMM), the fault types of bearings are diagnosed. Improved LMD is proposed based on the self-similarity of roller bearing vibration signal by extending the right and left side of the original signal to suppress its edge effect. First, the vibration signals of the ro...

For a rolling piston type of rotary compressor, oil supply system consisting of individual lubrication elements such as pumps, oil passages, and sliding surfaces has been modeled by employing equivalent electric circuit. Numerical solutions of the oil network model include total oil flow rate into the shaft hole, oil flow rates to various sliding surfaces, and oil leaks through roller end clear...