1) DC motors can be divided into brushless DC motors and brushed DC motors according to their structures and working principles.
Brushed DC motors can be divided into permanent magnet DC motors and electromagnetic DC motors.
Electromagnetic DC motors are divided into series DC motors, parallel DC motors, separately excited DC motors and composite DC motors.
Permanent magnet DC motors are divided into rare earth permanent magnet DC motors, ferrite permanent magnet DC motors and Al-Ni-Co permanent magnet DC motors.
2) Among them, AC motors can also be divided into single-phase motors and three-phase motors.
2. According to the structure and working principle, it can be divided into DC motor, asynchronous motor and synchronous motor.
1) synchronous motors can be divided into permanent magnet synchronous motors, reluctance synchronous motors and hysteresis synchronous motors.
2) Asynchronous motors can be divided into induction motors and AC commutator motors.
Induction motors can be divided into three-phase asynchronous motors, single-phase asynchronous motors and shielded pole asynchronous motors.
AC commutator motor can be divided into single-phase series motor, AC -DC dual-purpose motor and repulsion motor.
3. According to the starting and running modes, it can be divided into three types: capacitor-started single-phase asynchronous motor, capacitor-operated single-phase asynchronous motor, capacitor-started single-phase asynchronous motor and split-phase single-phase asynchronous motor.
4. According to the purpose, it can be divided into drive motor and control motor.
1) drive motors can be divided into: motors for electric tools (including drilling, grinding, polishing, slotting, cutting, reaming, etc. ), motors for household appliances (including washing machines, electric fans, refrigerators, air conditioners, tape recorders, video recorders, DVD players, vacuum cleaners, cameras, hair dryers, electric razors, etc.). ) and other general small mechanical equipment (including various small machine tools).
2) Control motors are divided into stepper motors and servo motors.
5. According to the rotor structure, it can be divided into squirrel-cage induction motor (old standard called squirrel-cage asynchronous motor) and wound rotor induction motor (old standard called wound asynchronous motor).
6. According to the running speed, it can be divided into high-speed motor, low-speed motor, constant-speed motor and variable-speed motor. Low-speed motors are divided into gear reduction motors, electromagnetic reduction motors, torque motors and claw-pole synchronous motors.
Speed regulating motors can be divided into step constant speed motors, stepless constant speed motors, step variable speed motors and stepless variable speed motors, as well as electromagnetic speed regulating motors, DC speed regulating motors, PWM frequency conversion motor and switched reluctance speed regulating motors.
The rotor speed of asynchronous motor is always slightly lower than the synchronous speed of rotating magnetic field.
Regardless of the load, the rotor speed of the synchronous motor is always kept at the synchronous speed.
Extended data:
The working principle of DC generator is to use the commutation function of brush to change the AC electromotive force induced in armature coil into DC electromotive force when it is led out from the end of brush through commutator.
The direction of induced electromotive force is determined according to the right-hand rule (the magnetic induction line points to the palm, the thumb points to the direction of conductor movement, and the other four fingers point to the direction of induced electromotive force in the conductor).
Working principle: The stress direction of the conductor is determined by the left-handed rule. This pair of electromagnetic forces forms a torque acting on the armature, which is called electromagnetic torque in rotating electric machine. The direction of the torque is counterclockwise, in an attempt to make the armature rotate counterclockwise.
If this electromagnetic torque can overcome the resistance torque on the armature (such as the resistance torque caused by friction and other load torques), the armature can rotate counterclockwise.
DC motor is a kind of motor that runs on DC working voltage. Widely used in tape recorders, video recorders, DVD players, electric razors, hair dryers, electronic watches, toys and so on.
The excitation mode of DC motor refers to the problem of how to supply power to the excitation winding, generate excitation flux potential and establish the main magnetic field. According to different excitation modes, DC motors can be divided into the following types.
1 separately excited: the excitation winding is not connected with the armature winding. A DC motor powered by other DC sources is called a separately excited DC motor, and a permanent magnet DC motor can also be regarded as a separately excited DC motor.
2 shunt excitation: the excitation winding of shunt DC motor is connected in parallel with the armature winding. As a parallel generator, the terminal voltage from the motor itself supplies power to the excitation winding; As a shunt motor, the excitation winding and armature use the same power supply, and its performance is the same as that of separately excited DC motor.
Series excitation: the excitation winding of series-excited DC motor is connected in series with armature winding, and then connected to DC power supply. The excitation current of this DC motor is armature current.
Compound excitation: The compound excitation DC motor has two excitation windings, parallel excitation and series excitation. If the magnetic flux potential produced by series winding is in the same direction as that produced by parallel winding, it is called compound excitation. If the two magnetic flux potentials are in opposite directions, it is called differential compound excitation.
DC motors with different excitation modes have different characteristics. Generally speaking, the main excitation modes of DC motor are shunt excitation, series excitation and compound excitation, while the main excitation modes of DC generator are separate excitation, shunt excitation and compound excitation.
References:
Baidu encyclopedia-electric machinery