4 DC motor
The excitation mode of a DC motor refers to the problem of how to supply power to the field winding and generate a field magnetomotive force to establish a main magnetic field. DC motors can be classified into the following types depending on the excitation method.
Heli
The excitation winding has no connection relationship with the armature winding, and the DC motor that is powered by the other DC power supply to the excitation winding is called a separately excited DC motor, and the wiring is shown in Figure 1.23(a). In the figure, M denotes an electric motor, and if it is a generator, it is denoted by G. Permanent magnet DC motors can also be regarded as their excitation DC motors.
And encourage
The excitation winding of the DC motor is connected in parallel with the armature winding. As a shunt generator,
The terminal voltage from the motor itself supplies power to the field winding. As a shunt motor, the field winding and the armature share the same power source, which is the same as the performance of the DC motor.
String excitation
The excitation winding of the series-excited DC motor is connected in series with the armature winding, and then connected to the DC power supply. The excitation current of such a DC motor is the armature current.
Compound
The compound-excited DC motor has two excitation windings, shunt and series excitation. If the magnetomotive force generated by the series excitation winding is the same as the direction of the magnetomotive force generated by the shunt winding, it is called product recombination. If the two magnetomotive forces are opposite in direction, they are called differential complex excitation.
DC motors with different excitation methods have different characteristics. In general, the main excitation methods of DC motors are shunt-type, series-excitation and compound-excitation. The main excitation modes of DC generators are the overexcitation, shunt-excitation and compound-excitation modes.
