Dynamic performance analyze of swing angle torque permanent magnet motor under different structure and winding parameters
A swing angle torque permanent magnet motor operating mechanism is presented which applied in the high voltage circuit breaker. The motor is a permanent magnet motor with limited angle and only working in the starting stage. Based on the operation requirement of high voltage circuit breaker, the dynamic performance of driving motor operating mechanism is achieved by employing the finite element method. The parameters behavior of driving motor is obtained under the different structure and winding parameters, such as the length to diameter ratio, turns and line width ratio, thickness of permanent magnet, pole arc coefficient, length of air-gap and operating voltage. The results indicate that the motor operating mechanism have a good mechanical characteristics and reach the operation of high voltage circuit breaker.
Design of a Novel Permanent Magnet Brushless DC Motor-Driven Operating Mechanism for High-Voltage Circuit Breaker and Its Dynamic Simulation
To improve the reliability of high-voltage circuit breakers,a novel operating mechanism,i.e.,a limited rotating angle permanent magnetic brushless DC motor-driven operating mechanism,is developed.According to the requirement to mechanical characteristic of 40.5 kV vacuum circuit breaker,the structure of the driving motor and its main parameters,including electric load,magnetic load,pole number,pole-arc coefficient and so on,are designed.The dynamic characteristic of the designed prototype is simulated by finite element method.Simulation results show that the design of the permanent magnetic brushless DC motor is reasonable,its mechanical characteristics,such as electromagnetic torque,current,rotating speed and rotating angle,etc.
Effects of reservoir volume on performance of pulse tube cooler.
A pulse tube cooler has the advantages of long-life and low-vibration over conventional cryocoolers such as G-M and Stirling coolers because of the absence of moving parts at low temperature. On the other hand, the combination of a reservoir and orifice is indispensable to optimize the performance of pulse tube coolers. In order to make the pulse tube cooler compact for practical applications, the volume of reservoir should be minimized. This paper analyzes the effects of the reservoir volume on the thermodynamic performance of various components in a simple orifice and a double-inlet pulse tube cooler by combining a linearized model with a thermodynamic analysis. Expressions of entropy production for those components are presented. The results show that the reservoir volume has a significant influence on the entropy production in the various components when the reservoir to pulse tube volume ratio is smaller than about 5. The ratio is important to determine the minimum reservoir volume for a pulse tube cooler. Optimum settings for a double-inlet pulse tube cooler are also discussed.