| Recently, the application of submersible motor in agricultural irrigation, oil extraction, rescue and relief and other important cases is becoming more and more common. With the development of national economy and the stimulation of market demand, our country has developed the maximum power of 4000 kW submersible motors in the world. High-power submersible motor has two important features. One feature is to adopt the closed-slot stator lamination, and the second is to adopt multiple-plane end windings. Due to the unique operating environment of submersible motor, the closed slot submersible motor can greatly weaken the water frictional loss, and multiple-plane end winding can effectively reduce the end winding temperature rise. Since the magnetic saturation located in the slot bridge of closed slot submersible motor, Carter Factor is no longer equal to 1. Hence, to seek effective computing method of closed slot Carter Factor of submersible motor is of great significance. In the steady state running process, the stator end winding of submersible motor is easily to suffer alternating electromagnetic force and vibration. Since the submersible motor develops in the direction of high power, the electromagnetic force of stator end windings is more and more large, and the long-term running can cause insulation abrasion and fatigue, and even cause motor failure. Therefore, research on electromagnetic vibration of high power closed slot submersible motor is of great theoretical guiding significance for design and optimization of the submersible motor, and has some practical value in engineering.Based on the characteristics of high magnetic saturation in closed slot submersible motor, the equivalent permeance method and the geometry method were proposed for the Carter Factor calculation of closed slot submersible motor. And the calculation results were compared to the results obtained by finite element method. The equivalent permeance method can take the high magnetic saturation into consideration and the geometry method is suitable for fast calculation of Carter Factor in the engineering. Based on the characteristics of high magnetic saturation in slot bridges, analysis of slot leakage reactance of the different-slot-type motor during starting process and the rotor surface losses duiring no load condition were performed.The three-dimensional end region model of submersible motor was establised, and the time-stepping finite element method as well as the time-harmonic finite element method was adopted to solve the harmonic leakage magnetic field of end region. Then the improved analytical method and the finite element method were used to calculate the end winding lekage inductance of the closed slot submersible motor. The eddy current losses in end region of closed slot submersible motor were analyzed and the solutions of weakening the eddy current losses were proposed. Moreover, the coupled magnetic-thermal fields in end region of closed slot submersible motor were studied. Finally, the three dimensional model of 2800kW, lOkV submersible motor was constructed for analyzing the electromagnetic forces of the end windings during starting transient operation and steady state running process. Based on this, the stress distributions and the deformations of the end windings were analyzed and the modal analysis and the harmonic response analysis were performed. Furtermore, the conclusions can provide good reference in solving the actual engineering problem and in optimal design of end winding as well as the operational reliability of submersible motor. |
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