Research On Key Technologies Of Low-Speed And Large Capacity Induction Motor With Positive-Pressure Explosion-Proof

The dissertation research object is the world's largest capacity of low-speed and large capacity induction motor with positive-pressure explosion-proof,and the key technologies are mainly studied in the dissertation.The motor is used in Zone 2?IIC?,and the main explosive gases are H₂ and C₂H₂,whose are flammable and explosive gases.Therefore,the explosion-proof performance of the motor is one of the key technologies.The motor capacity is as high as 6.5MW,and the huge motor capacity will produce more loss,higher current and higher torque,so the electrical performance of the motor is also one of the key technologies.The number of poles of the motor is 20P,and the very low speed of the motor reduces the ventilation capability dramatically,so the cooling performance of the motor is another key technology.For the explosion-proof performance of the motor,this dissertation applies the multi-component fluid theory to the positive-pressure explosion-proof motor for the first time.The explosion-proof performance of the motor is simulated and analyzed by using the finite element method.Through the concentration nephogram of each part,it can be known whether there is a dead angle of purging inside the motor,which enhances the safety performanceof the positive-pressure explosion-proof motor.The simulation results have been verified by the explosion proof test,and the calculated data meet the accuracy requirements.The optimized layout of the intake pipe improves the purging efficiency and saves the test cost.At the same time,it can make the motor start-up quickly and better service condition.Aiming at the electrical performance of large induction motors,this paper puts forward the idea of traction and fitting of test data and hypothesis testing method based on statistics.and the"electrical performance analysis system of large induction motors"is developed based on the magnetic circuit methodof electromagnetic design,which enhances the accuracy and reliability of large induction motor design scheme and improves the one-time qualification rate of large induction motors.At the same time,the design schemes can be quickly optimized by the system,which is beneficial to reduce the cost and improve the efficiency of large induction motors.Moreover,the system has humanized setting,PDM management concept and automatic drawing function,which makes the system more useful.The starting performance and operation performance of the motor are analyzed in detail to ensure the basic operation performance of the motor.Meanwhile,the performance of the motor under asymmetric,overloaded and locked operation conditions is also analyzed,so that users can take reasonable protection measures to reduce the damage to the motor and its related equipment.For the cooling performance of the motor,the subdomain method is used for the first time to study the motor fluid field in the dissertation.Through the analysis of the motor iron core domain,cooler inlet domain,fan cooler and cooler export domain,end domain,the wind resistance characteristic of each domain and the external characteristic of fan can be obtained,and thenthe system air volume were solved by graphical method again.The coincidence with the actual measured air volume of the prototype is high,which can solve the problem that ordinary computers can't calculate huge models.In addition,according to the product characteristics,the special structure of the cooler is designed,the of fluid field and temperature field cooler is simulated and analyzed by the whole domain coupling method.The temperature rise is carried out,and the wind temperature and the wind speed of prototype are in good agreement with those of calculation,which reach expected requirement.It shows that the structure of the special cooler that designed is reasonable,the solution method and model established in the dissertation are correct,and the internal structure of the cooler is optimized to further improve its performance,which provides a theoretical basis for the optimization design of the cooler in the future.