The basic working principle of dc motor
According to different power supply mode, the machine has two types of dc motor and ac motor. Computer used in the cooling fan motor for dc motor, for + 12 v power supply voltage, speed between 1000-10000 revolutions per minute.
dc motor is a dc can be converted into mechanical energy of rotating machinery. It is composed of stator and rotor commutator and the three parts, as shown in figure 1.
figure 1 has the structure of the brushless dc motor stator (
The main pole) Are fixed on the fan support, is the rotating part of the motor. There are more than two sets of
in the rotor coil, the enameled wire winding and become, called winding. A magnetic field when the winding of an electric current passes through, the function of the magnetic field and stator magnetic field to produce force. Because of the stator is fixed, so the rotor turning under the action of force.
is a kind of special equipment of dc motor commutator, is composed of many commutator segment, each of the two adjacent commutator segment is insulation piece in the middle. With a spring pressure on the surface of the commutator brush, with external connection rotation of the armature winding. Turned a certain Angle, when the rotor commutator access another pair will supply voltage winding, and continue to produce magnetic field in the winding. Visible, but because of the commutator, the armature coil by electromagnetic torque remains unchanged, in under the action of the electromagnetic torque to rotate the armature, as shown in figure 4.
figure 2 diagram
the rotor brushless dc motor using the bearing clearance fit between the shell and implementation. Fan blades fixed on the rotor, thus, when the rotor rotation, with the rotor blades will turn up. Ball bearing (commonly used ordinary fan As shown in figure 3) High-grade fan, and in order to improve the operation stability and increase the service life, usually adopt more advanced liquid bearing ( As shown in figure 4) 。
figure 3 ball bearing
4 liquid bearing structure
