机电技术专业英语 教学课件 作者 徐起贺 张庆良pata a lesson Twenty seven.pptVIP

* 机电技术专业英语 Lesson Twenty-seven Text Circuit An electric circuit (or network) is an interconnection of physical electrical devices. The purpose of electric circuits is to distribute and convert energy into some other forms. Accordingly, the basic circuit components are an energy source (or sources), an energy converter (or converters) and conductors connecting them. An energy source (a primary or secondary cell, a generator and the like) converts chemicals, mechanical, thermal or some other forms of energy into electric energy. An energy converter, also called load (such as a lamp, heating appliance or electric motor), converts electric energy into light, heat, mechanical work and so on. Circuit and Motors Lesson Twenty-seven The Construction and Components of a Typical Electric Motor Electric motors are by far the most ubiquitous of the actuators, occurring in virtually all electromechanical systems3. Figure A29 illustrates the construction and components of a typical electric motor. The stationary outer housing, called the stator, supports radial magnetized poles. These poles consist of either permanent magnets or wire coils, called field coils, wrapped around laminated iron cores. The purpose of the stator poles is to provide radial magnetic fields. Figure A29?The Construction and Components of a Typical Electric Motor1.stator winding; 2.frame; 3.stator core; 4.connection box; 5.rotor core; 6.rotor winding; 7.slip ring Lesson Twenty-seven DC Motors Direct current motors are used in a large number of mechatronics designs because of the torquespeed characteristics achievable with different electrical configurations. DC motor speeds can be smoothly controlled and in most cases are revertible5. Lesson Twenty-seven New Words and Expressions Lesson Twenty-seven Lesson Twenty-seven Lesson Twenty-seven Lesson Twenty-seven Lesson Twenty-seven Lesson Twenty-seven Notes 1. The terminals of the source and load are interconnected by cond