Operating Principle of Motor

Motors are devices that convert electrical energy into mechanical energy. It uses the energized coil (that is, the stator winding) to generate a rotating magnetic field and act on the rotor squirrel-cage closed aluminum frame to form the magneto-electrodynamic rotating torque. Motors are divided into DC motors and AC motors according to the different power sources used. Most of the motors in the power system are AC motors, which can be synchronous motors or asynchronous motors (the speed of the stator magnetic field of the motor is not synchronous with the speed of the rotor rotation). The motor is mainly composed of stator and rotor. The direction of force movement of energized wire in the magnetic field is related to the direction of current and magnetic induction line (magnetic field direction). The working principle of the motor is that the magnetic field acts on the force of the current to make the motor rotate.

 

Basic introduction

The motor is a rotating electric machine, which converts electrical energy into mechanical energy. It mainly includes an electromagnet winding or distributed stator winding used to generate magnetic field and a rotating armature or rotor. Under the action of the rotating magnetic field of the stator winding, the armature squirrel-cage aluminum frame is rotated by the current passing through and the magnetic field. Some of these machines can be used as motors or generators. It is a machine that converts electrical energy into mechanical energy. Usually, the working part of the motor rotates, which is called rotor motor; There are also linear motion, called linear motor.

 

Basic structure

The structure of three-phase asynchronous motor is composed of stator, rotor and other accessories.

Stator (stationary part)
 

1. Stator core

Function: It is a part of the magnetic circuit of the motor, on which the stator winding is placed.

Structure: The stator core is generally made of 0.35-0.5mm thick silicon steel sheet with insulating layer on the surface and laminated. There are evenly distributed slots punched in the inner circle of the core to embed the stator winding.

 

The stator core slot types are as follows:

Semi-closed slot: the efficiency and power factor of the motor are high, but the winding embedding and insulation are difficult. Generally used in small low-voltage motors.

Semi-opening slot: it can embed the formed winding, and is generally used for large and medium-sized low-voltage motors. The so-called formed winding means that the winding can be put into the slot after insulation treatment in advance.

Open-type slot: It is used to embed the formed winding, and the insulation method is convenient. It is mainly used in high-voltage motors.
 

2. Stator winding

Function: It is the circuit part of the motor, which is fed with three-phase alternating current to generate rotating magnetic field.

Structure: It is connected by three identical windings with 120 ° electrical angle separated from each other in space and arranged in parallel. Each coil of these windings is embedded in each slot of the stator according to certain rules.

The main insulation items of the stator winding are as follows: (ensure the reliable insulation between the conductive parts of the winding and the iron core as well as the reliable insulation between the winding itself).

(1) Ground insulation: the insulation between the whole stator winding and the stator core.

(2) Inter-phase insulation: insulation between stator windings of each phase.

(3) Inter-turn insulation: insulation between each wire turn of each phase stator winding.

 

3. Base

Function: fix the stator core and front and rear end covers to support the rotor and play the role of protection and heat dissipation.

Structure: The frame is usually cast iron, the frame of large asynchronous motor is generally welded with steel plate, and the frame of micro motor is made of cast aluminum. There are cooling ribs on the outside of the frame of the enclosed motor to increase the heat dissipation area. The end covers at both ends of the frame of the protective motor are provided with ventilation holes, so that the air inside and outside the motor can be directly convection to facilitate heat dissipation.

 

SIVO Motor has a technical management team with strong professional skills and management ability. The main products include iron shell single three-phase asynchronous motor series, aluminum shell single three-phase synchronous motor series, fan special motor series, variable frequency motor series, permanent magnet DC motor series, etc. Welcome to contact us with any motor problems.