Permanent magnet dc motor
Permanent magnet dc motor is also composed of stator magnetic pole, rotor, brush, case and so on. Stator magnetic pole is made of permanent magnet (permanent magnet steel) with materials such as ferrite, alnico, ndfeb. According to its structur form, it can be divided into cylinder type and tile type and so on. Most of the electricity used in the video recorder is cylindrical magnets, while most of the electric tools and motors used in automobile appliances are made of special block magnets.
Generally, the rotor is made of silicon steel laminated, which has less slots than the electromagnetic dc motor. Most of the small power motors used in the VCR are 3 slots, and the higher ones are 5 or 7 slots. Enameled wire is wound between two slots in the rotor core (three slots are provided with three windings), and its joints are separately welded on the metal sheet of the commutator. Electric brush is a conductive part connecting power supply and rotor winding. Permanent magnet motor brush uses single metal sheet or metallic graphite brush, electrochemical graphite brush.
The permanent magnet dc motor used in the video recorder adopts the electronic speed stabilizing circuit or centrifugal speed stabilizing device.