they are classifed as trucks,passengsr cars and special purp

英语翻译
motor,pm dc motors can be classifed accroding to commutation scheme and armature design.conventional dc motors have mechanical brushes and commutators.in one important class of dc motors the commutation is done electronically this type of motor is called a brushless dc motor.
the rotor and stator configuration fo an iron-core pm dc motor is shown in figure 5.2.2the permanent-magnet material can be barium-ferrite,alnico,or rare-eath compound.the magnetic flux produced by the magnet passes through a liminated rotor structure that contains slots.the armature conductors are placed in the rotor slots.this tope of dc motor is characterized by relatively hige rotor inertia (since the rotating part consists of the armatuer windings) high inductance,low cost,and high reliability.