There are many related terms about DC motors, and today we will introduce the no-load magnetic field of DC motors. Let's see what kind of state this is?
We refer to the operating state of a DC motor without load as no-load operation, where the current in the motor is almost zero, and the no-load magnetic field is the magnetic field generated by the main magnetic pole in this situation. What is the reason for this? When the current passes through the excitation winding in the motor, the generated magnetic flux enters the armature teeth and finally returns to the stator of the motor, forming a closed circuit.
The path through which such a main magnetic flux passes is called the main magnetic circuit, mainly composed of several parts such as the main magnetic pole, air gap, armature teeth, armature yoke, and stator yoke. But there will also be another part of the magnetic flux that does not pass through the air gap, which can directly pass through adjacent magnetic poles or stator yokes to form a closed circuit.
The size of the no-load magnetic field of the motor is closely related to the air gap size and magnetic flux density, which affects the operation of the motor. So it is necessary to carry out appropriate control to ensure that the motor operates normally.