Excitation mode refers to the way of producing magnetic field in rotating motor. The excitation mode of DC motor can be divided into four kinds:

separately excited DC machine

There is no connection between excitation winding and armature winding. DC motor supplied by other DC power supply to excitation winding is called external excitation DC motor. Permanent magnet DC motor can also be regarded as other excitation or self-excited DC motor, generally called excitation mode as permanent magnet.

shunt DC machine

the exciting winding of the shunt-excited direct current motor is connected in parallel with the armature winding, The performance is the same as that of the other DC motor.

series DC machine

The excitation winding of series excitation DC motor is connected to DC power supply after series with armature winding. The excitation current of this kind of DC motor is armature current.

compound DC machine

The compound-excited DC motor has a shunt and a series of exciting windings. The magnetic flux potential generated by the series-excitation winding is the same as the direction of the magnetic flux potential generated by the shunt winding. If the direction of the two magnetic flux potential is opposite, 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 parallel excitation, series excitation and compound excitation. The main excitation modes of DC generator are other excitation, parallel excitation and compound excitation.