DC motor and permanent magnet motor
Direct current
The working principle of the DC generator is to induce the alternating electromotive force in the armature coil.
By the commutator and the commutation of the brush, it becomes the principle of DC electromotive force when it is taken out from the brush end.
The direction of the induced electromotive force is determined according to the right-hand rule (the magnetic line is pointing to the palm of the hand, the thumb is pointing to the direction of movement of the conductor, and the other four fingers are pointing in the direction of the induced electromotive force in the conductor).
working principle
The direction of the conductor's force is determined by the left-hand rule. This pair of electromagnetic forces forms a moment acting on the armature. This torque is called electromagnetic torque in the rotating machine. The direction of the torque is counterclockwise, in an attempt to rotate the armature counterclockwise. If this electromagnetic torque can overcome the resistive torque on the armature (such as the resistive torque caused by friction and other load torque), the armature can be rotated counterclockwise.
DC motors are motors that operate on DC operating voltage and are widely used in recorders, video recorders, DVD players, electric shavers, hair dryers, electronic watches, toys, etc.
Permanent magnet
The permanent magnet type DC motor is also composed of a stator pole, a rotor, a brush, a casing, etc. The stator pole is made of a permanent magnet (permanent magnet), and has ferrite, aluminium nickel cobalt, neodymium iron boron and the like. According to its structural form, it can be divided into cylindrical type and tile type. Most of the electric motors used in VCRs are cylindrical magnets, while most of the motors used in electric tools and automotive appliances use block magnets.
The rotor is generally laminated with silicon steel sheets, which has fewer slots than the electromagnetic DC motor rotor. Most of the low-power motors used in VCRs are 3 slots, and the higher gears are 5 slots or 7 slots. The enameled wire is wound between the two slots of the rotor core (three slots have three windings), and the joints are respectively welded to the metal piece of the commutator. The brush is a conductive component that connects the power supply to the rotor winding, and has both electrical and wear resistance properties. The brush of the permanent magnet motor uses a single metal sheet or a metal graphite brush or an electrochemical graphite brush.
The permanent magnet type DC motor used in the VCR uses an electronic steady speed circuit or a centrifugal steady speed device.
