All motors work by switching the magnetic axis of rotation. A DC motor applies DC to the commutator through a friction brush, switching the applied current to the windings with alternating polarity, similar to AC, but a square wave of positive and negative voltages. This creates an alternating electromagnet that interacts with the permanent magnet on the rotor, constantly pulling, then pushing and providing rotational motion.
Thus, DC motors share many similarities with AC motors in that they periodically alternate polarity power supplies, but the DC power model requires some additional components.
The structure of DC motor is more complex, more expensive than AC motor, maintenance is also more difficult. In recent years, with the development of frequency conversion technology, AC motor has gradually replaced DC motor in the field of medium and small power motor speed regulation. However, DC motor has the advantages of smooth speed regulation, convenient speed regulation, wide speed range, large starting torque and so on. It is widely used in the production machinery that requires smooth speed regulation, wide speed range or flexible starting brake control. In particular, the work device with higher speed regulation requirements (especially the high-power work device) is still driven by DC motor. In fact, with the development of power electronics technology, DC motor speed regulation technology is constantly developing and improving. Dc motor is a motor that converts DC electric energy into mechanical energy. Because of its good speed control performance, it is widely used in electric drive.
One of the main advantages of DC motors is their low speed performance. Of course, they can also be driven at high speeds, but a DC motor may be preferred if the load has to adjust speed quickly, or if it requires excellent torque at low speeds (which may take a long time to accelerate).
The stator always has a pair of stationary main magnetic poles N and S excited by DC, and an armature core is installed on the rotating part of the rotor. The head and tail of the coil are respectively connected to two circular curved copper pieces, and the commutator pieces are insulated from each other. When the armature rotates, the armature coil is connected to the external circuit through the commutator plate and the brush. The role of the main magnetic pole of the stator part is to establish the main magnetic field. The main magnetic pole of the vast majority of DC motors is not a magnet, but the field is established by the excitation winding with DC current.
The armature core of the rotor part is a component of the main magnetic circuit, and the armature winding is composed of a certain number of armature coils connected according to a certain law. It is the circuit part of the DC motor, producing induced electromotive force and converting electromechanical energy. The commutator mainly plays the role of rectification in the DC generator.
