文档介绍：专业英语论文翻译
院院电气工程学院
专业电气工程及其自动化
班级电气(2)
姓名阿克巴尔江
学号 P081613382
Page1 Generators and Motors(发电机和电动机)
1 English text
From reference 1
1. Direct-current generators impress on the line a direct or continuous emf, one that is always in the same direction. Commercial dc generators mutators, which distinguish them from ac generators. The function of mutator and the elementary ideas of generation of emf mutation are discussed in Div. 1. Additional information mutation as applied to dc motors, which in general is true for dc generators, is given below.
2. Excitation of generator fields. To generate an emf, conductors must cut a ic field which mercial machines must be relatively strong. A permanent can be used for producing such a field in a generator of small output, such as a telephone o or the o of an insulation tester, but in generators for light and power the
field is produced by s, which may be excited by the machine itself or be separately excited from another -excited machines may be of the series, shunt, pound type, depending upon the manner of connecting the field winding to the armature. In the series type of machine,the field winding (the winding which produces the ic field) is connected in series with the armature winding. In the shunt type, the field winding is connected in parallel,shunt, with the armature winding. Compound machines have two field windings on each pole. One of these windings is connected in series with the armature winding, and the other is connected in parallel or shunt with the armature winding.
3. Armature winding of dc machines may be of the lap or the wave type. The difference in the two types is in the manner of connecting the armature coils to coil is the portion of the armature winding between essive connections to the lap type of winding (see Fig. ) the two ends of a coil are connected to mutator segments. In the wave type of winding (see Fig. ) the two ends of a coil are connected