Miniature Synchronous Motors
The rated power of miniature synchronous motors ranges from a few watts to hundreds of watts, as the speed of synchronous motors does not vary with the load within a certain output power range. They are widely used in precision tools and mixers, controllers or recording devices.
Miniature synchronous motor according to the stator winding connected to the power supply phase, can be divided into two categories of three-phase and single-phase synchronous motor. The stator structure of three-phase miniature synchronous motor is the same as that of ordinary three-phase synchronous motor. In the stator core slot embedded in the three-phase winding with a difference of 120 ° electrical angle. When working, it is powered by three-phase power supply. The stator structure of single-phase miniature synchronous motor is the same as that of single-phase asynchronous motor, which is divided into two-phase starting type and shaded pole type. When working, it is powered by single-phase power supply.
Basic structure of micro synchronous motor
In this part, we mainly come to know the basic structure of miniature synchronous motor.
1,Stator
The stator of synchronous motor is called armature, the structure is the same as that of three-phase asynchronous motor, which is composed of stator core, stator winding, seat and end cover. The stator core consists of silicon steel sheet, and the three symmetrical windings are embedded in the slot of the core.
2,Rotor
The rotor consists of rotor core, excitation winding, start winding and rotor shaft. The rotor core is made of cast steel or forged steel, with the excitation winding wound on it. The excitation winding is connected to the excitation power supply to access the excitation current. Start winding by embedded in the magnetic pole surface of the copper strip copper strip ends with copper ring connection, with the same as the asynchronous motor squirrel cage rotor. The rotor of three-phase synchronous motor has two types: hidden pole type and convex pole type.
The hidden pole rotor core is cylindrical, with grooves on the surface and excitation windings embedded in the grooves, and the air gap between the stator core is relatively uniform. Convex pole type rotor excitation winding is concentrated around the core column between the two poles, and the breath between the stator core is not uniform.
Working Principle of Miniature Synchronous Motor
In this part, we mainly come to know the working principle of miniature synchronous motor.
Synchronous motor is a kind of AC motor, and its working principle is based on the principle of electromagnetic induction and electromagnetic mechanics. When the synchronous motor is connected to the power supply, the current forms a rotating magnetic field in the stator winding, and the rotating speed of this magnetic field depends on the frequency of the power supply and the number of poles of the stator winding. At the same time, a magnetic field also exists inside the rotor, which is provided by a DC power supply or a constant current source, and the number of poles of this magnetic field is the same as the number of poles of the stator winding.
When the speed of the stator rotating magnetic field is equal to the speed of the rotor magnetic field, the rotor starts to follow the stator rotation, when the synchronous motor reaches the synchronous speed. If the stator rotation speed changes, the rotor will lose synchronization, and then the
synchronous motor enters the slip state.
When the synchronous motor works, the three-phase stator windings are fed with three-phase symmetrical currents, and the excitation winding of the rotor is fed with DC currents. When three-phase alternating current is passed in the three-phase symmetrical winding of the stator, a rotating magnetic field will be generated in the air gap. When a DC current is passed in the rotor excitation winding, a static magnetic field with constant polarity will be generated. If the number of pole pairs of the rotor magnetic field is equal to the number of pole pairs of the stator magnetic field, the rotor magnetic field rotates synchronously with the stator rotating magnetic field due to the magnetic pull of the stator magnetic field, i.e., the rotor rotates at a speed and in a direction equal to the rotating magnetic field.
In the process of synchronous motor operation, due to the existence of the rotor magnetic field, the rotor will be subjected to electromagnetic force in the process of rotation, this electromagnetic force is called tension. The size of the pulling force depends on the relative position and size between the stator magnetic field and the rotor magnetic field, and the size of the pulling force changes when the relative position changes. Due to the existence of this pulling force, synchronous motors can produce large starting torque and running torque, and therefore are widely used in various industrial fields.
The above is to share with you about the miniature synchronous motor, I hope it will be helpful to you.
