Research On The Commutation And Related Issues Of Brushes Permanent Magnet Dc Motor

Brush DC motor is the traditional motor which uses brush to make current physical commutation. Compared to the induction motor and synchronous motor, the excellent speed performance, good starting performance, simple control and power quality and stability make DC motor has been widely used in car transportation, power generation systems, toy making, etc.Tthe use of brush-commutator device will bring wear, spark, noise and other mechanical/chemical problem. The performance of DC motor is closely related to the performance of commutation.Brush commutation is a phenomenon which contents multi-disciplinary subjects, is very difficult to be accurately described. Due to DC motor technology improvements and the economic indicators and special DC motor development, the classical theory have been able to solve for various problems. This is an urgent need for people to issue a further understanding of the commutation.This paper will focus on the math model of an permanent magnet DC motor commutation and of the problem arising by the commutation.A Permanent Magnet DC Motor for fan use were established two models. One is based on Ansoft Maxwell for finite element simulation of mathematical models. And the other is a full consideration to the brush contact resistance mathematical model.The former can be use in all types of DC motor and is convenient ; the latter will be constrainted by the type of the brush, the calculation is complicated. but its provides a high accuracy result for researchers.This paper conducted electromagnetic interference, brush wear and brush noise made model. According to conducted interference measurement principle, combined with EMC for high frequency to the model and simulation model, DC motor conduction disturbances established mathematical model of the circuit. And experimental validation by comparison of the model's reliability. This paper provides an wear formula in case of electrical current carrying under the theory of finite element theory, while establishing a motor brush wear rate used to query the database. Brush noise model put forward by the force on the commutator brush friction simulation analysis to explore the frequency distribution of noise.At last Visual Basic is developed a permanent magnet DC motor designed CAD program. The program will summarize the research above .