The principle of forward and reverse rotation of series motor

Principle of series motor

When powered by an AC power source, the principle of generating rotational torque can still be explained by the operating principle of a DC motor.

When there is current in a conductor, a magnetic field is generated around the conductor, and the direction of its magnetic lines of force depends on the direction of the current. When a conductor carrying current is placed in a magnetic field, the magnetic field interacts with the magnetic field generated by the conductor carrying current, causing the conductor to be subjected to a force F, and thus to move. The conductor will move from a place where the magnetic lines of force are dense to a direction where the magnetic lines of force are sparse. When a coil consisting of two conductors facing each other is placed in a magnetic field, the two sides of the coil are also subjected to forces, and the directions of these two forces are opposite, generating torque.

When the coil rotates in the magnetic field, the corresponding two coil sides move from one magnetic pole to another. At this time, due to the change in the polarity of the magnetic field, the direction of the force acting on the conductor will change, and the direction of the torque will also change, causing the coil to rotate in the opposite direction. Therefore, the coil can only swing back and forth around the central axis.

The forward and reverse rotation principle of the series-excited motor is similar to that of the DC motor, which is achieved by changing the relative polarity between the armature and the excitation winding. Specifically, when the series-excited motor rotates forward, the polarity of the armature and the excitation winding is the same, and a rotating magnetic field will be generated in the armature, which interacts with the excitation magnetic field to generate torque, thereby driving the motor to operate normally. When the motor is reversed, it is only necessary to change the polarity of the excitation winding to make it opposite to the polarity of the armature, thereby generating a reverse magnetic field and causing the motor to rotate in the opposite direction.

In practical applications, the forward and reverse control of the series-excited motor can be achieved in many ways, such as:

A mechanical reverser is used to change the polarity of the motor through mechanical manual operation, thereby achieving forward and reverse control;

Adopt electronic switch control, change the circuit connection mode of the motor by turning on and off the switch, so as to realize forward and reverse control;

Adopt intelligent motor controller, control and adjust the working state of the motor through program, and realize precise forward and reverse control and speed regulation function.

In short, the forward and reverse principle of the series-excited motor is relatively simple, but the realization of forward and reverse control still needs to consider many factors, such as circuit connection, control signal, torque characteristics, etc., to ensure the normal operation and safety of the motor. In specific applications, the appropriate forward and reverse control method and equipment should be selected according to the actual situation to meet different engineering needs and technical requirements.