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The analytical methods are widely used to predict the vibration and noise of the permanent magnet motors in industry applications. In the traditional analytical method, the influence of the teeth is ignored and a large error of vibration calculation will occur in the slotted motor. In this article, a high-precision analytical method is proposed for vibration calculation of motors based on tooth modeling. First, the electromagnetic forces on each tooth of stator of the motor under no load and load are calculated. Then, the transfer function from the force acting on the teeth to the vibration on the surface of the shell is derived and verified by finite-element method (FEM). Next, the superposition method is introduced and used to superimpose the vibration excited by the force of all teeth to calculate the total vibration acceleration of the motor surface. Finally, the FEM and experiments are conducted to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

There is only slot frequency electromagnetic vibration and no pole frequency vibration in rotating armature permanent magnet motor (RAPMM), which is the advantage of this motor. The open of slot makes the air-gap magnetic field distorted and causes the harmonic of electromagnetic excitation force. In order to reduce the slot frequency vibration of the RAPMM, the method of placing magnetic slot wedge (MSW) at the slot opening is put forward accordingly. Through the finite-element simulation, it is finally shown that the MSW is capable of weakening the harmonic of the air-gap flux density, as well as decreasing the high-frequency component of the electromagnetic excitation force. Therefore, it is acknowledged that MSW can suppress the cogging torque and the vibration of corresponding frequency on the stator significantly. Finally, it is confirmed by the experiments that the built-in MSW is an effective measure for reducing the vibration of the RAPMM. [ABSTRACT FROM AUTHOR]

The multiphase synchronous generator‐rectifier system could provide an ideal DC power source for more electric aircraft (MEA). When the inter‐turn short‐circuit fault occurs in phase windings of the generator, a large short‐circuit current would be introduced inside the armature windings, which could cause severe damages to the system for overheat in the windings and irons as well as huge electromagnetic forces on the end coils. To improve the reliability of the MEA, this study researches on the inter‐turn fault of the multiphase generator‐rectifier system including the theoretical analysis, numerical simulation and experiment verification. A 12‐phase system is taken, for example, and a multi‐loop mathematical model is built up to calculate all voltages and currents in the multiphase synchronous generator‐rectifier system with armature inter‐turn fault. Many factors are thoroughly considered in the model including the location and short turns of fault, space harmonics of the air‐gap magnetic field and the changing circuit topology of the system. Moreover, the mathematical model is verified by fault experiment results. Moreover, the electric characteristics of the fault are summarised, which could provide a quantitative basis for early detection of the inter‐turn faults in the multiphase generator‐rectifier system. [ABSTRACT FROM AUTHOR]