The working principle and superiority of DC motor

The direction of the conductor's force is determined by the left-hand rule. This pair of electromagnetic forces forms a moment that acts on the armature. This moment is called electromagnetic torque in a rotating electrical machine. The direction of the torque is counterclockwise in an attempt to make the armature rotate counterclockwise. If this electromagnetic torque can overcome the resistance torque on the armature (such as resistance torque caused by friction and other load torques), the armature can rotate in a counterclockwise direction.
A DC motor is a motor that runs on a DC working voltage and is widely used in tape recorders, video recorders, DVD players, electric shavers, hair dryers, electronic watches, toys, etc.

DC motors have fast response, large starting torque, and can provide rated torque performance from zero speed to rated speed, but the advantages of DC motors are also its shortcomings, because DC motors have to generate constant rotation under rated load. For torque performance, the armature magnetic field and the rotor magnetic field must be maintained at 90° constantly, which requires the use of carbon brushes and commutators. Carbon brushes and commutators will generate sparks and carbon powder when the motor rotates. Therefore, in addition to damage to the components, the use occasions are also restricted. AC motors do not have carbon brushes and commutators. They are maintenance-free, sturdy, and widely used. However, in order to achieve the performance equivalent to DC motors, complex control techniques can be used to achieve them. Nowadays, the rapid development of semiconductors has accelerated the switching frequency of power components to improve the performance of the drive motor. The speed of the microprocessor is also getting faster and faster, which can realize the control of the AC motor in a rotating two-axis Cartesian coordinate system, and appropriately control the current components of the AC motor in the two axes, so as to achieve the control similar to the DC motor and have the equivalent of the DC motor. performance.