What are the five categories of DC servo motors : According to the way the magnetic field is generated, DC motors can be divided into five types: separate excitation type, permanent magnet type, parallel excitation type, series excitation type and complex excitation type. The permanent magnet type uses soft magnetic materials such as oxides, aluminum-nickel drills, and rare earth to establish an exciting magnetic field. Structurally, DC servo motors are general armature type, slotless armature type, printed armature type, wound disc type and hollow cup armature type. To avoid brush commutator contact, there are also brushless DC servo motors. According to the control method, the DC servo motor can be divided into the magnetic field control method and the armature control method. Obviously. The hydromagnetic DC servo motor can only use the armature control method, and most of the general electric-input DC servo motors also use the armature control method. In CNC machine tools, the commonly used DC servo motors for feeding systems mainly include the following: (1) Small inertia DC servo motor The small inertia direct sinking servo motor is named because of the small rotating inertia basin. This type of motor is generally of the hydromagnetic type, and the armature winding has three types: phase-free armature type, printed armature type and hollow cup armature type. Because the small inertia DC motor minimizes the moment of inertia of the armature. So you can get the fastest response time. on early CNC machines. This type of servo motor is widely used. Xiao Xie sees that servo motors are still used in CNC machine tools in some countries. such as France. (2) DC torque motor Also known as large inertia wide speed DC servo motor. On the one hand, due to its larger rotor diameter. The number of coil winding turns is increased. High torque. The rotation of the rice bowl is larger than other types of motors. And can work for a long time under large overload torque. Therefore, it can be directly connected with the lead screw, without the need for an intermediate transmission. On the other hand, since it has no excitation circuit losses, its size is smaller than other similar DC servo motors. It also has a prominent feature that it can run smoothly at a lower speed, and the minimum speed can reach 1r/min or even 0.1r/min. therefore. This kind of servo motor has been widely used in CNC machine tools. (3) Brushless DC Servo Motor This kind of servo motor is also called a commutatorless motor. It has no commutator. It consists of a synchronous motor and an inverter, which is controlled by a rotor position sensor mounted on the rotor. It is essentially an AC speed regulating motor, and its speed regulating performance can reach the level of a DC servo generator. The commutation device and brush parts are also cancelled, which greatly improves the service life of the motor. Classification of DC Servo Motors_Structure of DC Servo Motors Structure of DC Servo Motor 1. The rotor, also known as the armature, is made of laminated silicon steel sheets, and the surface is embedded with coils. When DC is applied, an electromagnetic torque is generated to drive the load to rotate under the action of the stator magnetic field. 2. Brushes and commutator segments, in order to keep the generated electromagnetic torque in a constant direction, the rotor can rotate uniformly and continuously along the fixed direction, the brushes are connected to the external DC power supply, and the commutator segments are connected to the armature conductors. 2. Stator, the magnetic field of the stator pole is generated by the magnetic pole of the stator. According to the way of generating the magnetic field, DC servo motors can be divided into permanent magnet type and separately excited type. The permanent magnet pole is made of permanent magnet material, and the other excitation pole is laminated by stamping silicon steel sheets, and the outer coil is connected with a DC current to generate a constant magnetic field.
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